Patent Publication Number: US-2022228161-A1

Title: Plant serine proteases

Description:
Incorporated by reference in its entirety herein is a computer-readable sequence listing and identified as follows: One 138,364_Byte ASCII (Text) file named “Sequence_Listing_ST25.txt,” created on Nov. 29, 2021. 
     TECHNICAL FIELD 
     The present invention relates to the field of the production of recombinant proteins and other polypeptides in plants. 
     BACKGROUND ART 
     Many proteins, in particular in eukaryotic systems, are susceptible to proteolytic enzymes (proteases). 
     Unwanted proteolysis is important because it may alter physical and chemical properties, conformation, distribution, stability, activity, folding and consequently, function of the proteins. Moreover, many proteins show significantly less or no activity when they are modified by proteases. Secreted proteins, membrane proteins and proteins targeted to vesicles or certain intracellular organelles are likely to be exposed to proteases during their biosynthesis or post harvesting. Types of human proteins which often undergo proteolysis include serum proteins, antibodies, metal carriers, enzymes, coagulation factors, protease inhibitors, extracellular matrix proteins, growth factors and hormones. The sequences targeted by the proteases sometimes contain the amino acids lysine or arginine at the two positions preceding the cleaved peptide bond. However, other sequence motifs recognized by proteases are also known. The proteases responsible for these cleavage reactions are typically derived from extracellular fluids or components of the secretory machinery of eukaryotic cells (e.g. Golgi apparatus, lysosomes or related compartments). 
     Proteases as well as their regulation play an important role in tobacco plants for modulating the curing of the leaves of said tobacco plants (see WO 2016/009006). Controlling the expression of subtilisin-like serine endopeptidase-like proteins in plants allows the manipulation of water and/or CO2 exchange through plant stomata (see WO 2013/192545). 
     As mentioned above the preservation of the full-length sequence is often essential for the biological activity of polypeptides and proteins. This has to be considered when host cells are selected to be used for the recombinant production of polypeptides and proteins. 
     US 2004/106198 discloses a system for the expression of heterologous protease sensitive proteins in a plant cell. 
     Especially the recombinant expression of animal polypeptides and proteins in plants or plant cells often requires a modification of the host cell to prevent proteolysis of the polypeptides and proteins to be expressed. However, targeted strategies to protect recombinantly produced proteins of animal origin in plant cells against proteolytic degradation depend on knowledge of the responsible proteases, which have not been identified yet. 
     It is therefore an object of the present invention to provide methods and means enabling a host cell, preferably of non-animal origin, to prevent the unwanted proteolysis of a recombinant protein, preferably derived from an animal, based on the identity and properties of the proteases involved therein. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a genetically modified plant or plant cell derived from a wild-type plant or plant cell, said wild-type plant or plant cell producing at least one serine protease comprising the motif SSRGPX 1 LKPDX 2 X 3 APGX 4 SGTSMSCPHX 5 PX 6 WSPX 7 AX 8 X 9 SAX 10 MTT (SEQ ID No. 1), wherein 
     X 1  is a peptide consisting of 7 amino acid residues, X 2  is I or L, X 3  is T or M, X 4  is a peptide consisting of 27 or 28 amino acid residues, X 5  is a peptide consisting of 12 amino acid residues, X 6  is T or E, X 7  is S or A, X 8  is V or I, X 9  is K or R and X 10  is I or M, wherein the proteolytic activity of the at least one serine protease in the genetically modified plant or plant cell is reduced compared to its activity in the wild-type plant or plant cell, wherein the genetically modified plant or plant cell comprises at least one exogenous nucleic acid molecule encoding for at least one protein or polypeptide of interest. It turned surprisingly out that proteolysis of proteins and polypeptides recombinantly produced in plant cells could be significantly reduced or even completely prevented when the activity of at least one serine protease as mentioned above is significantly reduced or prevented. 
     Another aspect of the present invention relates to a serine protease consisting of an amino acid sequence selected from the group consisting of SEQ ID No. 2, SEQ ID No. 4, SEQ ID No. 6, SEQ ID No. 8, SEQ ID No. 10, SEQ ID No. 14, SEQ ID No. 16, SEQ ID No. 20 and SEQ ID No. 22, preferably SEQ ID No. 2 or SEQ ID No. 14. 
     A further aspect of the present invention relates to a nucleic acid molecule encoding a serine protease according to the present invention. 
     Another aspect of the present invention relates to a method for producing at least one protein or polypeptide of interest by cultivating a genetically modified plant or plant cell according to the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows the time-dependent degradation of 2F5, 2G12 and PG9 by proteases present in apoplastic fluid obtained from  Nicotiana benthamiana  C105 leaves. A characteristic heavy-chain (hc) degradation product (*) is produced due to cleavage within or close to the complementarity-determining region (CDR) H3 loop. The identified cleavage sites are shown in Table 1. 
         FIG. 2 a - c    shows that cleaved 2F5, 2G12 and PG9 have a much lower antigen-binding activity than the intact antibodies as determined by ELISA with the respective cognate antigens as ligands. The constant domains of the antibodies are proteolysis-resistant under the conditions used, as demonstrated by equal binding of anti-Fc antibodies. 
         FIG. 3  shows that the dissociation constant of cleaved 2F5 for its antigen gp41 peptide is far higher than for the intact antibody as determined by surface plasmon resonance (SPR) spectroscopy. 
         FIG. 4 a - b    show that purified SBT1 and SBT2 can cleave the heavy chains of 2F5, 2G12 and PG9 at the same positions as apoplastic fluid. The observed cleavage sites (listed in Tables 2 and 3) are identical to those observed for apoplastic fluid. Other serine proteases (trypsin, SBT3) cannot cleave the monoclonal antibody 2F5 at these positions. 
         FIG. 5 a - h    shows that SBT1 and SBT2 are effectively inhibited by subtilisin propeptide-like inhibitors. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The reduction of the proteolytic activity of the at least one serine protease of the present invention comprising the motif consisting of SEQ ID No. 1 in plants and plant cells resulted surprisingly in a reduction of the proteolysis of exogenous polypeptides and proteins synthesised in said plants and plant cells. 
     Serine proteases are able to cleave peptide bonds in proteins and polypeptides, in which serine serves as the nucleophilic amino acid at the enzyme&#39;s active site. Serine proteases are characterised by a distinctive structure, consisting of two domains that converge at the catalytic active site. Furthermore, these proteases are usually categorised based on their substrate specificity as either trypsin-like, chymotrypsin-like, thrombin-like, subtilisin-like or elastase-like. The serine proteases of the present invention whose proteolytic activity shall be reduced are preferably subtilisin-like serine proteases. 
     According to a preferred embodiment of the present invention the protease is a plant protease, preferably a serine protease, more preferably a subtilisin-like serine protease, preferably from  Nicotiana  spp., more preferably from  Nicotiana benthamiana , in particular from the  Nicotiana benthamiana  line C105 (Strasser R et al. Plant Biotechnol J 6(2008):392-402). 
     The term “plant cell”, as used herein, refers to protoplasts, gamete producing cells and cells which regenerate into whole plants. Plant cells, as used herein, further include cells obtained from or found in seeds, suspension cultures, embryos, meristematic regions, callus tissue, leaves, roots, shoots, gametophytes, sporophytes, pollen and microspores. 
     “Proteolytic activity” of enzymes refers to their ability to cleave peptide bonds present in polypeptides and proteins. Proteolytic activity can be measured by using methods known in the art (e.g. Twining, 1984, Anal. Biochem. 143, 30-34). 
     The serine protease motif of the present invention having SEQ ID No. 1 comprises at positions X 1 , X 4  and X 5  peptides consisting of a defined length. However, the composition of these peptides in relation to amino acid residues is variable. 
     The motif of the serine protease of the present invention is SSRGPX 1 LKPDX 2 X 3 APGX 4 SGTSMSCPHX 5 PX 6 WSPX 7 AX 8 X 9 SAX 10 MTT (SEQ ID No. 1), wherein X 1  is a peptide consisting of 7 amino acid residues, X 2  is I or L, X 3  is T or M, X 4  is a peptide consisting of 27 or 28 amino acid residues, X 5  is a peptide consisting of 12 amino acid residues, X 6  is T or E, X 7  is S or A, X 8  is V or I, X 9  is K or R and X 10  is I or M. 
     According to another preferred embodiment of the present invention the at least one serine protease has at least 80%, preferably at least 85%, more preferably at least 90%, more preferably at least 95%, more preferably at least 96%, more preferably at least 98%, more preferably at least 99%, in particular 100%, sequence identity to a serine protease consisting of an amino acid sequence selected from the group consisting of SEQ ID No. 2, SEQ ID No. 4, SEQ ID No. 6, SEQ ID No. 8, SEQ ID No. 10, SEQ ID No. 14, SEQ ID No. 16, SEQ ID No. 18, SEQ ID No. 20 and SEQ ID No. 22, most preferably SEQ ID No. 2 or SEQ ID No. 14. 
     “% sequence identity”, as used herein, is obtained by aligning two sequences to be compared to give a maximum correlation between the sequences. This may include inserting “gaps” in either one or both sequences, to enhance the degree of alignment. A % identity may then be determined over the whole length of each of the sequences being compared. In the above context, an amino acid sequence having a “sequence identity” of at least, for example, 80% to a query amino acid sequence, is intended to mean that the sequence of the subject amino acid sequence is identical to the query sequence except that the subject amino acid sequence may include up to twenty amino acid alterations per each 100 amino acids of the query amino acid sequence. In other words, to obtain an amino acid sequence having a sequence of at least 80% identity to a query amino acid sequence, up to 20% (20 of 100) of the amino acid residues in the subject sequence may be inserted or substituted with another amino acid or deleted. 
     Methods for comparing the identity of two or even more sequences are well known in the art. The percentage to which two sequences are identical can for example be determined by using a mathematical algorithm. Such algorithms are integrated in the BLAST family of programs, e.g. BLAST or NBLAST program (see also Altschul et al., 1990, J. Mol. Biol. 215, 403-410 or Altschul et al., 1997, Nucleic Acids Res., 25, 3389-3402), accessible through the home page of the NCBI (www.ncbi.nlm.nih.gov). According to the present invention sequence identity is preferably determined using the following parameters: Matrix BLOSUM62; Open gap 11 and extension gap 1 penalties; gap x_dropoff50; expect 10.0 word size 3; Filter: none. 
     According to a further preferred embodiment of the present invention the protease is encoded by a nucleic acid sequence selected from the group consisting of SEQ ID No. 3, SEQ ID No. 5, SEQ ID No. 7, SEQ ID No. 9, SEQ ID No. 11, SEQ ID No. 15, SEQ ID No. 17, SEQ ID No. 19, SEQ ID No. 21 and SEQ ID No. 23, preferably SEQ ID No. 3 or SEQ ID No. 15. 
     Particularly preferred is a  Nicotiana benthamiana  subtilisin-like serine protease (SBT1) comprising amino acid sequence SEQ ID No. 2, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 109, of SEQ ID No. 2 represent the signal peptide and propeptide region. The amino acids of the catalytic triad (Asp148, His215, Ser553) are underlined: 
     
       
         
           
               
            
               
                 (SEQ ID No. 2) 
               
               
                 MKGIISLFFCFSLFIVSFILREADSASQAQNNGIYIVYMGAAASSNGGTR 
               
               
                   
               
               
                 HDQARLISSLIRRNKHAVVHSYNNGFSGFAARLSESEAKSMAQRPGVISV 
               
               
                   
               
               
                 FPDPVLQLHTTHSWDFLKYQTDEKINSSPSSGSDSSLIGADTIIGIL D TG 
               
               
                   
               
               
                 IWPESESFNDKDMGPIPSRWNGTCMDGQDFGSSKCNKKIVGARFYEESDD 
               
               
                   
               
               
                 SGTKIAGSARDENG H GTHVASTAAGSPVAGASYYGLAAGTATGGSPGSRI 
               
               
                   
               
               
                 SMYRVCTTFGCRGSAIMKAFDDAIADGVDVLSLSLGSSPGLEPDFPSNPI 
               
               
                   
               
               
                 AIGAFHAVEKGITVVCSAGNSGPGPKTVVNTAPWILTVAATTIDRDFETD 
               
               
                   
               
               
                 IVLGGNKLIKGGGINFGNMTKSSVYPLIHGNSTKSNDNVSEADARSCVPG 
               
               
                   
               
               
                 SLDENKVKGKIVLCENLDDGEYFPSDKLDEVKSRGGVGFILIDDDERTVA 
               
               
                   
               
               
                 PKFNSFSAGVVSKKDGNEILAYINSTRNPVASILPTVSITKYKPAPVVAY 
               
               
                   
               
               
                 FSSRGPAYNTPNLLKPDITAPGVAILAAWPGNDTSEALPGQKPPIFNLLS 
               
               
                   
               
               
                 GT S MSCPHVSGIAATVKAVNPTWSPSAVKSAIMTTAIQTNNLKAPITTVS 
               
               
                   
               
               
                 GSKATPYDIGAGEASTSGPLKPGLVYETDVADYLQFLCSVGFNISQIKLI 
               
               
                   
               
               
                 SITVPEDFSCPKNSTSELVSNMNYPSIAISSLKENEPKKVTRTVTNTGEE 
               
               
                   
               
               
                 ASVYTTVIEAPKGLEVQVIPTKLEFTNKSKKLSYDVSFKASSTSKEDLFG 
               
               
                   
               
               
                 SITWTNGKYKVRSPFVVSSN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Nicotiana benthamiana  subtilisin-like serine protease may comprise SEQ ID No. 3, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 327, of SEQ ID No. 3 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 3) 
               
               
                 atgaaaggaattatatctttgtttttctgcttttctcttttcattgtctc 
               
               
                   
               
               
                 tttcatattaagagaagccgactcagcttctcaagcacaaaacaatggaa 
               
               
                   
               
               
                 tttatattgtttatatgggtgctgcagcttcatctaatggtggtaccaga 
               
               
                   
               
               
                 catgatcaagcgcggcttatcagctccttgatcagaaggaacaagcatgc 
               
               
                   
               
               
                 agtggtacacagctacaacaatggtttctcaggattcgcggcacgtttat 
               
               
                   
               
               
                 cagaatctgaagctaaatccatggctcaaagacctggagttatctccgta 
               
               
                   
               
               
                 tttcctgatccagtactgcaactccacactacacattcatgggatttctt 
               
               
                   
               
               
                 gaagtatcaaactgatgaaaaaatcaattcaagtccaagctctggttctg 
               
               
                   
               
               
                 attcatcattaattggagctgataccataattggcatattggatacgggt 
               
               
                   
               
               
                 atatggccagaatctgagagtttcaatgacaaggatatgggtccaattcc 
               
               
                   
               
               
                 atcccggtggaatggaacttgcatggatggtcaagattttggctcttcaa 
               
               
                   
               
               
                 aatgcaacaagaagatagttggtgcaagattttatgaggagtctgatgac 
               
               
                   
               
               
                 agtggaacaaaaatcgctggatcagccagggacgagaacggacatggtac 
               
               
                   
               
               
                 tcatgttgcgtctactgcagctgggagtcctgttgcaggtgcatcctact 
               
               
                   
               
               
                 atggcctagctgcaggaactgccacgggtggatctcctggttcgaggatt 
               
               
                   
               
               
                 tccatgtatcgtgtctgtactacttttggatgccgcggatcagctatcat 
               
               
                   
               
               
                 gaaagcattcgatgatgcaattgcagatggggttgatgttttatcactat 
               
               
                   
               
               
                 cacttggttcatcacctggacttgaacctgattttccaagcaatcctatt 
               
               
                   
               
               
                 gccataggagcatttcatgctgtagaaaagggcattactgttgtttgctc 
               
               
                   
               
               
                 tgctggaaatagtggccctggaccaaaaactgttgtcaatacagctcctt 
               
               
                   
               
               
                 ggattcttactgttgcagccaccaccattgatcgtgacttcgagacagat 
               
               
                   
               
               
                 attgtcttgggtggaaacaagcttattaagggtggaggtataaactttgg 
               
               
                   
               
               
                 taacatgacaaaatcgtcagtctaccctttgattcatggcaattcaacca 
               
               
                   
               
               
                 aatcaaacgataatgtttctgaggcggatgcaaggagttgtgttcctggt 
               
               
                   
               
               
                 tcattagatgaaaacaaagtcaaggggaagattgtcctttgtgaaaatct 
               
               
                   
               
               
                 tgatgatggtgaatattttcccagtgacaagctagatgaagtgaaaagcc 
               
               
                   
               
               
                 gaggtggagttggatttatacttatagatgatgatgaaagaactgtggca 
               
               
                   
               
               
                 cccaaattcaattccttctcagctggtgtagtctctaaaaaggatggaaa 
               
               
                   
               
               
                 tgagatcctcgcctacattaactcgacgaggaatccagttgcatcaattt 
               
               
                   
               
               
                 taccaactgtatccataacaaagtacaaaccagctccagttgtggcttac 
               
               
                   
               
               
                 ttctcatcaagaggccctgcgtacaacacccctaacctcctcaaaccgga 
               
               
                   
               
               
                 tattacagcaccaggggttgccattcttgctgcttggcctggaaatgaca 
               
               
                   
               
               
                 cgagtgaggctctccccggccaaaaaccaccaattttcaacctactctca 
               
               
                   
               
               
                 ggcacttccatgtcctgccctcatgtatccggtattgctgctactgtcaa 
               
               
                   
               
               
                 agcagtaaaccctacctggagtccttcagctgtcaaatcagctattatga 
               
               
                   
               
               
                 ccacagctattcagacaaacaatttgaaggctccaatcactacagtctca 
               
               
                   
               
               
                 ggatccaaagcaacaccatatgacataggtgcaggagaagcaagcacttc 
               
               
                   
               
               
                 aggtccattaaaaccaggtctagtctacgagacagatgtcgccgactact 
               
               
                   
               
               
                 tgcagttcctatgttctgttggttttaacatatcacagataaagctgatc 
               
               
                   
               
               
                 tcaattacagttcctgaagacttttcatgcccaaaaaactcaacctctga 
               
               
                   
               
               
                 attggtttctaatatgaattatccatcaatagctatttctagtctcaaag 
               
               
                   
               
               
                 aaaacgagccgaagaaagttactagaactgtaacaaatactggtgaagaa 
               
               
                   
               
               
                 gcatcagtatatactacagttattgaggcaccaaaaggattggaagtcca 
               
               
                   
               
               
                 agtgatcccaactaaattggaatttacaaataaaagcaagaaattaagct 
               
               
                   
               
               
                 atgatgtgtctttcaaagcttcatctacctcaaaggaagatctgtttgga 
               
               
                   
               
               
                 tcaattacttggactaatggtaagtacaaagtccggagtccattcgtcgt 
               
               
                   
               
               
                 aagtagcaactaa 
               
            
           
         
       
     
     Particularly preferred is a  Nicotiana tabacum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 4, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 107, of SEQ ID No. 4 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 4) 
               
               
                 MKGLSLFFCFSLFIVAFIREADSASQAQNNGIYIVYMGAAASSNGGTRHD 
               
               
                   
               
               
                 QAQLISSLIRRNKNAVVHSYNNGFSGFAARLSEAEAKSMAQRPGVISVFP 
               
               
                   
               
               
                 DPVLQLHTTHSWDFLKYQTDEKINSSPSSGSDSSLIGADTIIGILDTGIW 
               
               
                   
               
               
                 PESESFNDKDMGPIPARWNGTCMDGQDFGSSKCNKKIVGARFYEESDDSG 
               
               
                   
               
               
                 IKIAGSARDENGHGTHVASTAAGSPVAGASYYGLAAGTATGGSPGSRIAM 
               
               
                   
               
               
                 YRVCTTFGCRGSAIMKAFDDAIADGVDVLSLSLGSSPGLEPDFPSNPIAI 
               
               
                   
               
               
                 GAFHAVEKGIVVVCSAGNSGPGPKTVVNTAPWILTVAATTIDRDFETDIV 
               
               
                   
               
               
                 LGGNKLIKGGGINFGNMTKSSVYPLIHGNSTKSNNNVSEADARSCVPGSL 
               
               
                   
               
               
                 DENKVKGKIVLCENLDDGEYFPSDKLDEVKSRGGVGFILIDDDERTVAPK 
               
               
                   
               
               
                 FNSFPAGVVSKKDGTEILAYINSTRNPIASILPTVSITKYKPAPVVAYFS 
               
               
                   
               
               
                 SRGPAYNTPNLLKPDITAPGVAILAAWPGNDTSEALPGQKPPIFNLLSGT 
               
               
                   
               
               
                 SMSCPHVSGIAATVKAVNPAWSPSAVKSAIMTTAIQINNLKAPITTVSGS 
               
               
                   
               
               
                 KATPYDIGAGEASTSGPLKPGLVYETDVADYLQFLCSAGFNISQIKLISS 
               
               
                   
               
               
                 TVPKDFSCPKNPTSELVSNMNYPSIAISSLKENEPKKVTRTVTNTGEEAS 
               
               
                   
               
               
                 VYTAIIEAPKGLEVQVIPSKLEFNYKSKKLSYEVSFKASSPSKEDLFGSI 
               
               
                   
               
               
                 TWTNGKYKVRSPFVVSSN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Nicotiana tabacum  subtilisin-like serine protease may comprise SEQ ID No. 5, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 321, of SEQ ID No. 5 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 5) 
               
               
                 atgaaaggcctttctttgttcttctgcttttctcttttcattgtcgcttt 
               
               
                   
               
               
                 cataagagaagccgactcagcttctcaagcacaaaacaatggcatttata 
               
               
                   
               
               
                 ttgtttatatgggtgctgcggcttcttctaacggtggtaccagacatgat 
               
               
                   
               
               
                 caagcgcagcttatcagctccttgatcagaaggaacaagaatgcagtggt 
               
               
                   
               
               
                 acacagctacaacaatggtttctcaggattcgcggcacgtttatcagaag 
               
               
                   
               
               
                 ctgaagctaaatccatggctcaaagacctggagttatctctgtatttcct 
               
               
                   
               
               
                 gatccagtactgcaactccacactacacattcatgggatttcttgaagta 
               
               
                   
               
               
                 tcaaactgatgaaaaaatcaattcaagtccaagctctggttctgattcat 
               
               
                   
               
               
                 cattaattggagctgataccataattggcatattggatacgggtatatgg 
               
               
                   
               
               
                 ccagaatctgagagtttcaatgacaaggatatgggtccaattccagcccg 
               
               
                   
               
               
                 gtggaatggaacttgcatggatggtcaagattttggctcttcaaaatgca 
               
               
                   
               
               
                 acaagaagatagttggtgcaagattttatgaggagtctgatgacagtgga 
               
               
                   
               
               
                 ataaaaatcgctggatcagccagggacgagaacggacatggtactcatgt 
               
               
                   
               
               
                 tgcgtctactgcagctgggagtcctgttgcaggtgcatcctactatggcc 
               
               
                   
               
               
                 tagctgcaggaactgccacgggtggatctcctggttcaaggattgccatg 
               
               
                   
               
               
                 tatcgtgtctgtactacttttggatgccgtggatcagctatcatgaaagc 
               
               
                   
               
               
                 attcgatgacgcaattgcagatggggttgatgttttatcactatcacttg 
               
               
                   
               
               
                 gttcatcacccggacttgaacctgattttccgagcaatcctattgccata 
               
               
                   
               
               
                 ggagcatttcatgccgtagaaaagggcattgttgttgtttgctctgctgg 
               
               
                   
               
               
                 aaatagtggccctggcccaaaaactgttgtcaatacagctccttggattc 
               
               
                   
               
               
                 taacggttgcagccaccaccattgatcgtgacttcgagacagatattgtc 
               
               
                   
               
               
                 ttgggtggaaacaagcttattaagggtggaggtataaactttggtaacat 
               
               
                   
               
               
                 gacaaaatcgtcagtctaccctttgattcatggcaattcaaccaaatcaa 
               
               
                   
               
               
                 acaataatgtttctgaggcggatgcaaggagttgtgttcctggttcatta 
               
               
                   
               
               
                 gatgaaaacaaagtcaaggggaagattgttctttgtgaaaatcttgatga 
               
               
                   
               
               
                 tggcgaatattttcccagtgacaagctagacgaagtgaagagtcgaggtg 
               
               
                   
               
               
                 gagttggatttatactaatagatgatgatgaaagaactgtggcacccaaa 
               
               
                   
               
               
                 ttcaattccttcccagcaggtgtagtctctaaaaaggatggtactgagat 
               
               
                   
               
               
                 ccttgcctacattaactcgactaggaatcccattgcatcaattttaccaa 
               
               
                   
               
               
                 ctgtttccataacaaagtacaaaccagctccagttgtcgcttacttctca 
               
               
                   
               
               
                 tcaagaggccctgcgtacaacacccctaacctcctcaaaccggatattac 
               
               
                   
               
               
                 agcaccaggggttgccattcttgctgcttggcctggaaatgacacgagtg 
               
               
                   
               
               
                 aggctctccccggccaaaaaccaccaattttcaacctactctcaggcact 
               
               
                   
               
               
                 tccatgtcctgccctcacgtatccggtattgctgcaactgtcaaagcagt 
               
               
                   
               
               
                 taaccctgcctggagtccttcagctgtcaaatcagctattatgaccacag 
               
               
                   
               
               
                 ctattcagataaacaatttgaaggctccaatcactacagtctcaggatcc 
               
               
                   
               
               
                 aaagcaacaccatatgacataggtgcaggagaagcaagcacttcaggtcc 
               
               
                   
               
               
                 attaaaaccaggtctagtctacgagacagatgtcgccgactacttgcagt 
               
               
                   
               
               
                 tcctatgttctgctggctttaacatatcacagataaagctgatctcaagt 
               
               
                   
               
               
                 acagttcctaaggacttttcatgcccaaaaaacccaacctctgaattggt 
               
               
                   
               
               
                 ttctaatatgaattatccatcaatagctatttctagtctcaaagaaaacg 
               
               
                   
               
               
                 agccgaagaaagttactagaacagttacaaatactggtgaagaagcatca 
               
               
                   
               
               
                 gtatatactgcaatcattgaggcaccaaaaggattggaagtccaagtgat 
               
               
                   
               
               
                 tccaagtaaattggaatttaattataaaagcaagaaattaagctatgaag 
               
               
                   
               
               
                 tgtctttcaaagcttcatctccctcaaaggaggatctgtttggctcaatt 
               
               
                   
               
               
                 acttggacaaatggtaagtacaaagtccggagtccatttgttgtaagtag 
               
               
                   
               
               
                 caactaa 
               
            
           
         
       
     
     Particularly preferred is a  Nicotiana tabacum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 6, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 107, of SEQ ID No. 6 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 6) 
               
               
                 MKGLFLFICFSLFIVSFIIEADSASQSQNNGIYIVYMGAAASSNGGTRHD 
               
               
                   
               
               
                 QAQLISSLIRRNKNAVVHSYKNGFSGFAARLSEAEAKSMAQRPGVVSVFP 
               
               
                   
               
               
                 DPVLQLHTTHSWDFLKYQTDEKINSSPSSGSDSSLIGADTIIGILDTGIW 
               
               
                   
               
               
                 PESESFNDKDMGPIPARWNGTCMDGQDFGSSNCNKKIVGARFYEESDDSG 
               
               
                   
               
               
                 IKITGSARDENGHGTHVASTAAGSPVAGASYYGLAAGTATGGSPGSRIAM 
               
               
                   
               
               
                 YRVCTTFGCRGSAIMKAFDDAIADGVDVLSLSLGSSPGLEPDFPTNPIAI 
               
               
                   
               
               
                 GAFHAVEKGIVVVCSAGNSGPGPKTVVNTAPWILTVAATTIDRDFETDVL 
               
               
                   
               
               
                 LGGNKLIKGGGINFGNMTKSTVYPLIHGNSTKSNDNVSEADARSCVPGSL 
               
               
                   
               
               
                 DENKVKGKIVLCENLDDGEYFPSDKLDEVKSRGGVGFILIDDDERTVAPK 
               
               
                   
               
               
                 FKAFPAGVVSKKDGTEILAYINSTRNPVASILPTISITKYKPAPVVAYFS 
               
               
                   
               
               
                 SRGPAYNTPNLLKPDITAPGVAILAAWPGNDTSEALPGQKPPIFNLLSGT 
               
               
                   
               
               
                 SMSCPHVSGIAATVKAVNPTWSPSAVKSAIMTTAIQTNNLKAPITTVSGS 
               
               
                   
               
               
                 KATPYDIGAGEASTSGPLKPGLVYETDVADYLQFLCSVGFNISQIKLISS 
               
               
                   
               
               
                 TVPKDFSCPKNSSSELVSNMNYPSIATSSLKENEPKKVTRTVTNTGEEAS 
               
               
                   
               
               
                 VYTAIIEAPKGLEVQVIPTKLEFTNKRKKVSYDVSFKASSTSKEDLFGSI 
               
               
                   
               
               
                 TWTNGKYKVRSPFVVSSN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Nicotiana tabacum  subtilisin-like serine protease may comprise SEQ ID No. 7, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 321, of SEQ ID No. 7 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 7) 
               
               
                 atgaaaggcctttttttgttcatatgcttctctcttttcattgtctcttt 
               
               
                   
               
               
                 cataatagaagccgactcagcttctcaatcacaaaacaatggcatttata 
               
               
                   
               
               
                 ttgtttatatgggtgctgcggcttcatctaacggtggtaccagacatgat 
               
               
                   
               
               
                 caagcgcagcttatcagctccttgatcagaaggaacaagaatgcagtggt 
               
               
                   
               
               
                 acacagctacaagaatggtttctcaggatttgcggcacgtttatcagaag 
               
               
                   
               
               
                 ctgaagctaaatcgatggctcaaagacctggagttgtctctgtatttcct 
               
               
                   
               
               
                 gatccagtactgcaactccacactacacattcatgggatttcttgaagta 
               
               
                   
               
               
                 tcaaactgatgaaaaaatcaattcaagtccaagctctggttctgattcat 
               
               
                   
               
               
                 cattaattggagctgataccataattggaatcttggatacgggtatatgg 
               
               
                   
               
               
                 ccagaatcagagagtttcaatgacaaggatatgggtccaattccagcccg 
               
               
                   
               
               
                 gtggaatggaacttgcatggatggtcaagattttggctcttccaattgca 
               
               
                   
               
               
                 acaagaagatagttggtgcaagattttatgaggagtctgatgacagtgga 
               
               
                   
               
               
                 ataaaaatcactggatcagccagggacgagaacggacatggtactcacgt 
               
               
                   
               
               
                 tgcatccactgcagctgggagccctgttgcaggtgcatcctactatggcc 
               
               
                   
               
               
                 tagctgcagggactgcaacaggtggatctccgggttccaggatcgccatg 
               
               
                   
               
               
                 tatcgtgtctgtactacttttggatgccgtggatcagctatcatgaaagc 
               
               
                   
               
               
                 attcgatgatgcaattgcagatggggttgatgttttatctctatcactcg 
               
               
                   
               
               
                 gttcatcacctggacttgaacctgattttccaaccaatcctattgccata 
               
               
                   
               
               
                 ggagcatttcatgccgtagaaaagggcattgttgttgtttgctctgctgg 
               
               
                   
               
               
                 aaatagtggccctggcccaaaaactgttgtcaatacagctccttggattc 
               
               
                   
               
               
                 ttactgttgcagccaccaccattgatcgtgacttcgagacagatgttctc 
               
               
                   
               
               
                 ttgggtggaaacaagttgattaagggtggaggtataaactttggtaacat 
               
               
                   
               
               
                 gacaaaatcaacagtctaccccttgattcatggcaattcaaccaaatcaa 
               
               
                   
               
               
                 acgataatgtttctgaggcagatgcaaggagttgtgttcctggttcatta 
               
               
                   
               
               
                 gatgaaaacaaagtcaaggggaagattgttctttgtgaaaatcttgatga 
               
               
                   
               
               
                 tggcgaatattttcccagtgacaagctagacgaagtgaagagtcgaggtg 
               
               
                   
               
               
                 gagttggatttatactaatagatgatgatgaaagaactgtggcacctaaa 
               
               
                   
               
               
                 ttcaaagccttcccagcgggtgtagtctctaaaaaggatggtactgagat 
               
               
                   
               
               
                 cctcgcctacattaactcgacaaggaatccagttgcatcaattttgccaa 
               
               
                   
               
               
                 ctatttccataacaaagtacaaaccagctccagttgttgcttacttctca 
               
               
                   
               
               
                 tcaagaggtcctgcatacaatacacctaacctcctcaaaccagatattac 
               
               
                   
               
               
                 agcaccaggggttgccattcttgctgcttggcctggaaatgacacgagtg 
               
               
                   
               
               
                 aggctctccccggccaaaaaccaccaattttcaacctactctcaggcact 
               
               
                   
               
               
                 tccatgtcctgccctcacgtttctggcattgctgcaacggtcaaagcagt 
               
               
                   
               
               
                 gaacccaacctggagtccttcagctgtcaaatcagctattatgaccacag 
               
               
                   
               
               
                 ctattcagacaaacaatttgaaggctccaatcactacagtctcaggatcc 
               
               
                   
               
               
                 aaagcaacaccatatgacataggagcaggagaagcaagcacttcaggtcc 
               
               
                   
               
               
                 attaaaaccaggtctagtctacgagacagatgtcgccgactacttgcagt 
               
               
                   
               
               
                 tcctctgttctgttggctttaacatatcacagataaagctgatctcaagt 
               
               
                   
               
               
                 acagttcctaaggacttttcatgcccaaaaaactcaagctctgaattggt 
               
               
                   
               
               
                 ttctaacatgaattatccttcaatagctacttctagtctcaaagaaaacg 
               
               
                   
               
               
                 agcccaagaaagttactagaactgttacaaatactggtgaagaagcatca 
               
               
                   
               
               
                 gtatatactgcaattattgaggcaccaaaaggattggaagtccaagtgat 
               
               
                   
               
               
                 tccaactaaattggaatttacaaataaaaggaagaaagtaagctatgatg 
               
               
                   
               
               
                 tatctttcaaagcctcatctacctcaaaggaagatctgtttggatcaatt 
               
               
                   
               
               
                 acttggacaaatggtaagtacaaagtccggagtccatttgtcgtaagtag 
               
               
                   
               
               
                 caactaa 
               
            
           
         
       
     
     Particularly preferred is a  Solanum lycopersicum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 8, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 107, of SEQ ID No. 8 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 8) 
               
               
                 MRDIVLFFCFLLFLLSLLRETNAVSQEKNNGVYIVYMGAADSSNDGTKNQ 
               
               
                   
               
               
                 QAELMSSLIKRKKDAVVHSYNNGFSGFAARLSEAEAKSIAQKPGVISVFP 
               
               
                   
               
               
                 DPILQLHTTRSWDFLQYQTEVESSSGPISGSDNASPKGVDTIIGILDTGI 
               
               
                   
               
               
                 WPESESFSDNDMSEVPSKWKGTCMGSHDSISFKCNKKLVGARFYDDSDED 
               
               
                   
               
               
                 GVRPFGSARDDNGHGTHVASTAAGSLISGASYYGLASGTAKGGSPGSRIA 
               
               
                   
               
               
                 MYRVCTADGCHGSAIMKAFDDAIADGVDVLSLSLGSSSGLEVEFSRDPIA 
               
               
                   
               
               
                 IGAFHAVEKGILVSCSAGNDGPGPATVVNVAPWILTVAATTIDRDFETDI 
               
               
                   
               
               
                 VLGGNKLIKGGGISLGNLTRSPVYPLISGDLAKSSNNVVMEKGARYCYPN 
               
               
                   
               
               
                 SLDETKVKGKIVLCDNRDGYFSLTEKLTEVKKKGGIGFILIDDNARTVAP 
               
               
                   
               
               
                 KFNSFPAAVVTEKDSNEILSYINSTKKPVASVLPTVTIANYKPAPLVAYF 
               
               
                   
               
               
                 SSRGPTYNTHNLLKPDITAPGVAILAAWPGNDTTEAVAGQALPLYNIISG 
               
               
                   
               
               
                 TSMSCPHVSGIAALVKAQNPSWSPSAIRSAIMTSALQTNNLKAPITTVSG 
               
               
                   
               
               
                 SVATPYDIGAGEASPSLALNPGLVYETNTADYLQYLCSVGYDKSKIKLIS 
               
               
                   
               
               
                 NTVPDDFSCPTNSSSESVSQMNYPSIAVSNIKENEIKKVTRTVTNVGQDD 
               
               
                   
               
               
                 ATYTASIKAPVGLEVQVTPNKLVFTNNSKKLSYEMSFKASSKPKEDLFGS 
               
               
                   
               
               
                 ITWTNGKYKVRSPFVISTNSQGEHSKTADRRSN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Solanum lycopersicum  subtilisin-like serine protease may comprise SEQ ID No. 9, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 321, of SEQ ID No. 9 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 9) 
               
               
                 atgagagacattgttctgtttttttgcttccttttatttttactctcttt 
               
               
                   
               
               
                 gcttagagaaactaatgcagtttctcaagaaaaaaacaatggtgtttata 
               
               
                   
               
               
                 ttgtttacatgggtgctgctgattcgtcgaacgatggcacgaaaaatcag 
               
               
                   
               
               
                 caagcagaactaatgagctcattgataaaaaggaaaaaggatgcagttgt 
               
               
                   
               
               
                 acacagttacaacaatggtttctcaggattcgcagcgcgtttatcagaag 
               
               
                   
               
               
                 ctgaggctaaatctattgctcaaaaacctggagttatatcagtattccct 
               
               
                   
               
               
                 gatccaatattgcaactacacacaacgcgttcgtgggactttttgcaata 
               
               
                   
               
               
                 tcaaactgaagtagaaagcagttctggtccaatatctggttctgataacg 
               
               
                   
               
               
                 cgtcaccaaaaggcgttgatactataattggaatcctggatacaggaata 
               
               
                   
               
               
                 tggcctgaatcagagagttttagtgataatgatatgagtgaagttccatc 
               
               
                   
               
               
                 taagtggaaaggaacttgtatgggaagtcatgattccatctctttcaaat 
               
               
                   
               
               
                 gcaacaagaagttagttggtgcaaggttctatgatgactctgatgaggat 
               
               
                   
               
               
                 ggtgtaagaccttttggttcagctagggatgataatggacatggaactca 
               
               
                   
               
               
                 tgttgcatctacagcagctgggagtttgatttcaggagcatcttattatg 
               
               
                   
               
               
                 gtttggcttctgggacagcaaagggtggatccccgggttcaagaatagcc 
               
               
                   
               
               
                 atgtatcgtgtctgcacggctgatggatgtcacggatcagctataatgaa 
               
               
                   
               
               
                 agcatttgatgatgcaattgcagatggggttgatgttttatcgctatcac 
               
               
                   
               
               
                 ttggttcatcatctggtcttgaagtcgagttttctagagatcctatagct 
               
               
                   
               
               
                 attggagcattccatgctgttgaaaagggaattcttgtttcctgttctgc 
               
               
                   
               
               
                 tggaaatgatggccctggtccggcaactgttgtcaatgttgcaccttgga 
               
               
                   
               
               
                 ttctcactgttgcagctactacaattgaccgtgacttcgagacagatatt 
               
               
                   
               
               
                 gtcttaggtggaaacaagttgataaagggaggaggtataagtttaggtaa 
               
               
                   
               
               
                 cttgacaagatctccagtatacccgttgattagtggcgatttagccaaat 
               
               
                   
               
               
                 ccagcaataatgttgttatggagaaaggtgcaaggtattgttatccgaat 
               
               
                   
               
               
                 tcattagatgaaaccaaagttaaggggaaaattgttctctgtgataatcg 
               
               
                   
               
               
                 cgacggatacttttcacttactgagaaactaacagaagtgaagaagaaag 
               
               
                   
               
               
                 gtggcattggatttatactaatagatgataatgcaagaactgtggcccca 
               
               
                   
               
               
                 aaattcaattcctttccagcagctgttgtaactgaaaaggatagcaatga 
               
               
                   
               
               
                 gatcctttcttacatcaactcaacaaagaaaccagttgcatcagttctgc 
               
               
                   
               
               
                 caactgttaccatagctaactacaaaccagctcctcttgtggcttacttc 
               
               
                   
               
               
                 tcatcaaggggtcctacatacaacacacataatctcctcaaaccagatat 
               
               
                   
               
               
                 tacagcaccaggtgttgcaattctcgcggcttggcctggaaacgacacaa 
               
               
                   
               
               
                 cagaggctgtcgctggccaggcgttaccactttacaacataatatcaggg 
               
               
                   
               
               
                 acttccatgtcctgccctcatgtttctggtattgccgcgttagtcaaggc 
               
               
                   
               
               
                 gcaaaatccttcttggagtccttcagcaatcagatcagctattatgacct 
               
               
                   
               
               
                 cagctttacagactaacaatttgaaggctccaatcacaacagtctctgga 
               
               
                   
               
               
                 tccgttgcaacaccatacgacataggagctggagaagcaagcccttcatt 
               
               
                   
               
               
                 ggcacttaatccaggattggtctacgagactaacaccgcagactacttgc 
               
               
                   
               
               
                 agtacctatgctcagttggctacgataaatcaaagataaaactcatttca 
               
               
                   
               
               
                 aatacagttcctgatgatttttcatgtcccaccaactcaagttctgaatc 
               
               
                   
               
               
                 cgtctcacaaatgaactacccttccattgctgtttcaaatatcaaagaaa 
               
               
                   
               
               
                 atgaaatcaagaaagtaacaagaactgtaactaacgtaggacaagacgac 
               
               
                   
               
               
                 gcaacatacacagcaagtataaaggcaccagttggtttggaagtccaagt 
               
               
                   
               
               
                 gaccccgaataaattggtatttacaaataatagcaagaagttgagctatg 
               
               
                   
               
               
                 aaatgtctttcaaagcttcatctaaaccaaaggaagacttgtttggatca 
               
               
                   
               
               
                 attacatggacaaatggtaaatacaaagtccgaagtccattcgttatatc 
               
               
                   
               
               
                 tactaattcacaaggtgaacactccaaaacagcagatcgcagatcaaact 
               
               
                   
               
               
                 ag 
               
            
           
         
       
     
     Particularly preferred is a  Solanum tuberosum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 10, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 107, of SEQ ID No. 10 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 10) 
               
               
                 MKVIVLFFCFFLLLLSFLRETNAVSQEKNNGVYIVYMGAADSSNDGTKNQ 
               
               
                   
               
               
                 RAELMSSLIRRKKDAVVHSYSNGFSGFAARLSEAEAKSIAQKPGVISVFP 
               
               
                   
               
               
                 DPILQLHTTRSWDFLQYQTEVESSSGPISGSDNASPKGVDTIIGILDTGI 
               
               
                   
               
               
                 WPESESFSDNDMSEVPSKWKGTCMASHDSISFKCNKKLVGARFYDDSDED 
               
               
                   
               
               
                 GVRPSGSARDENGHGTHVASTAAGSPISGASYYGLASGTAKGGSPGSRIA 
               
               
                   
               
               
                 MYRVCMTDGCHGSAIMKAFDDAIADGVDVLSLSLGSSSGLEVEFSSDPIA 
               
               
                   
               
               
                 IGAFHAVEKGILVSCSAGNDGPGPATVVNVAPWILTVAATTIDRDFETDI 
               
               
                   
               
               
                 VLGGNKLIKGGGISLGNLTRSPVYPLISGDLAKSGNTVVSEKNARFCNPN 
               
               
                   
               
               
                 SLDGTKVKGKVVLCDNRDGYYSLTEKLTEVKSKGGIGFIVVDDNARTVAP 
               
               
                   
               
               
                 KFKSFPAAVVTEKDSNEILSYINSTKKPVASVLPTVTIANYKPAPLVAYF 
               
               
                   
               
               
                 SSRGPTYNTHNLLKPDITAPGVAILAAWPGNDTNEAVAGQAPPLYNIISG 
               
               
                   
               
               
                 TSMSCPHVSGIAALVKAQNPSWSPSAIKSAIMTSALQTNNLKAPITTVSG 
               
               
                   
               
               
                 SVATPYDIGAGEASPSLALNPGLVYETNTADYLQYLCSVGYDKSKIKLIS 
               
               
                   
               
               
                 NTVPNDFSCPTNSSSESVSQMNYPSIAVSNIKENEIKKVTRTVTNVGQED 
               
               
                   
               
               
                 ATYTASIKAPVGLEVQVTPNKLVFTNNSKKLSYEVSFKASSKPKEDLFGS 
               
               
                   
               
               
                 ITWINGKYKVRSPFVVSTNSQGV 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Solanum tuberosum  subtilisin-like serine protease may comprise SEQ ID No. 11, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 321, of SEQ ID No. 11 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 11) 
               
               
                 atgaaagtcattgttctgtttttttgcttctttttattattactctcttt 
               
               
                   
               
               
                 tcttagagaaactaatgcagtttctcaagaaaaaaacaatggtgtataca 
               
               
                   
               
               
                 ttgtttacatgggcgctgctgattcgtcgaacgatggcacgaaaaatcag 
               
               
                   
               
               
                 cgagcagaacttatgagctctttgataagaagaaaaaaggatgcagttgt 
               
               
                   
               
               
                 acacagttacagcaatggtttctcaggattcgcagcgcgtttatcagaag 
               
               
                   
               
               
                 ctgaggctaaatccattgctcaaaaacctggagttatatcagtattccct 
               
               
                   
               
               
                 gatccaatattgcaactccacacaacgcgttcgtgggactttttgcaata 
               
               
                   
               
               
                 tcaaactgaagtagaaagcagttctggtccaatatcaggttctgataacg 
               
               
                   
               
               
                 cgtcaccaaaaggcgttgatactataattggaatcttggatacaggaata 
               
               
                   
               
               
                 tggcctgaatcagagagttttagtgataatgatatgagtgaagttccatc 
               
               
                   
               
               
                 taagtggaaaggaacttgtatggcaagtcatgattccatctctttcaaat 
               
               
                   
               
               
                 gcaacaagaagttagttggtgcaaggttctatgatgactctgatgaggat 
               
               
                   
               
               
                 ggtgtaagaccttctggttcagctagggatgagaatggacatggaactca 
               
               
                   
               
               
                 tgttgcatctacagcagctgggagtccgatttcaggagcatcttattatg 
               
               
                   
               
               
                 gtttggcttctgggaccgcgaagggtggatccccgggttcaagaatagcc 
               
               
                   
               
               
                 atgtatcgtgtctgcatgactgatggatgtcacggatcagctataatgaa 
               
               
                   
               
               
                 agcatttgatgatgcaattgcagatggggttgatgttttatcgctatcac 
               
               
                   
               
               
                 ttggttcatcatctggtcttgaagttgagttttcgagtgatcctatagct 
               
               
                   
               
               
                 attggagcattccatgctgttgaaaagggaattcttgtttcctgttctgc 
               
               
                   
               
               
                 tggaaatgatggccctggtccggcaactgttgtcaacgtcgcgccttgga 
               
               
                   
               
               
                 ttctcacagttgcagctactacaattgaccgtgacttcgagacagatatt 
               
               
                   
               
               
                 gtcttaggtggaaacaagttgattaagggtggaggtataagtcttggtaa 
               
               
                   
               
               
                 tttgacaagatctccagtatacccgttgattagtggcgatttagccaagt 
               
               
                   
               
               
                 ccggcaatactgttgtttcggagaaaaatgcaaggttttgtaatccgaat 
               
               
                   
               
               
                 tcattagatggaaccaaagttaaggggaaagttgttctttgtgataatcg 
               
               
                   
               
               
                 cgacggatactattcacttactgagaaactaacagaagtgaagagcaaag 
               
               
                   
               
               
                 gtggcattggatttatagtagtagatgataatgcaagaactgtggcacct 
               
               
                   
               
               
                 aaattcaaatcctttccagcagctgttgtaactgaaaaggatagcaatga 
               
               
                   
               
               
                 gatcctttcttacatcaactcaacaaagaaaccagttgcatcagttctgc 
               
               
                   
               
               
                 caactgttaccatagctaactacaaaccagctcctcttgtggcttacttc 
               
               
                   
               
               
                 tcatcaaggggtcctacatacaacacacataatctcctcaaaccagatat 
               
               
                   
               
               
                 tacagcaccaggtgttgcaattctcgcggcttggcctggaaacgacacaa 
               
               
                   
               
               
                 acgaggctgtcgctggccaggcgccaccactttacaacataatatcaggg 
               
               
                   
               
               
                 acttccatgtcctgccctcatgtttctggtattgccgcattagtcaaggc 
               
               
                   
               
               
                 gcaaaatccttcttggagtccttcagcaatcaaatcagctatcatgacct 
               
               
                   
               
               
                 cagctttacagactaacaatttgaaggctccaatcacaacagtctccggc 
               
               
                   
               
               
                 tccgttgcaacaccatacgacataggagctggagaagcaagcccttcatt 
               
               
                   
               
               
                 ggcacttaatccaggattggtctacgagactaacactgcagactacttgc 
               
               
                   
               
               
                 agtacctatgctcagttggctacgataaatcaaagataaaactcatctca 
               
               
                   
               
               
                 aatactgttcctaatgatttttcatgtcccaccaactcaagttctgaatc 
               
               
                   
               
               
                 cgtctcacaaatgaactacccttccattgctgtttcaaatatcaaagaaa 
               
               
                   
               
               
                 atgaaatcaagaaagtaacaagaactgtaactaacgtaggacaagaagac 
               
               
                   
               
               
                 gcaacatacacagcaagtataaaagcaccagttggtttggaagtccaagt 
               
               
                   
               
               
                 gaccccgaataaattggtatttacaaataatagcaagaagttgagctatg 
               
               
                   
               
               
                 aagtgtctttcaaagcttcatctaaaccaaaggaagacttgtttggatca 
               
               
                   
               
               
                 attacatggacaaatggtaaatacaaagtccgaagtccattcgttgtatc 
               
               
                   
               
               
                 tactaattcacaaggtgtctga 
               
            
           
         
       
     
     Another plant subtilisin-like serine protease of  Arabidopsis thaliana  may comprise amino acid sequence SEQ ID No. 12, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 108, of SEQ ID No. 12 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 12) 
               
               
                 MKGITFFTPFLSFLYLLCILFMTETEAGSRNGDGVYIVYMGSASSAANAN 
               
               
                   
               
               
                 RAQILINTMFKRRANDLLHTYKHGFSGFAARLTAEEAKVIAKKPGVVSVF 
               
               
                   
               
               
                 PDPHFQLHTTHSWDFLKYQTSVKVDSGPPSSASDGSYDSIVGILDTGIWP 
               
               
                   
               
               
                 ESESFNDKDMGPIPSRWKGTCMEAKDFKSSNCNRKIIGARYYKNPDDDSE 
               
               
                   
               
               
                 YYTTRDVIGHGSHVSSTIAGSAVENASYYGVASGTAKGGSQNARIAMYKV 
               
               
                   
               
               
                 CNPGGCTGSSILAAFDDAIADGVDVLSLSLGAPAYARIDLNTDPIAIGAF 
               
               
                   
               
               
                 HAVEQGILVICSAGNDGPDGGTVTNTAPWIMTVAANTIDRDFESDVVLGG 
               
               
                   
               
               
                 NKVIKGEGIHFSNVSKSPVYPLIHGKSAKSADASEGSARACDSDSLDQEK 
               
               
                   
               
               
                 VKGKIVLCENVGGSYYASSARDEVKSKGGTGCVFVDDRTRAVASAYGSFP 
               
               
                   
               
               
                 TTVIDSKEAAEIFSYLNSTKDPVATILPTATVEKFTPAPAVAYFSSRGPS 
               
               
                   
               
               
                 SLTRSILKPDITAPGVSILAAWTGNDSSISLEGKPASQYNVISGTSMAAP 
               
               
                   
               
               
                 HVSAVASLIKSQHPTWGPSAIRSAIMTTATQTNNDKGLITTETGATATPY 
               
               
                   
               
               
                 DSGAGELSSTASMQPGLVYETTETDYLNFLCYYGYNVTTIKAMSKAFPEN 
               
               
                   
               
               
                 FTCPADSNLDLISTINYPSIGISGFKGNGSKTVTRTVTNVGEDGEAVYTV 
               
               
                   
               
               
                 SVETPPGFNIQVTPEKLQFTKDGEKLTYQVIVSATASLKQDVFGALTWSN 
               
               
                   
               
               
                 AKYKVRSPIVISSESSRTN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Arabidopsis thaliana  subtilisin-like serine protease may comprise SEQ ID No. 13, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 324, of SEQ ID No. 13 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 13) 
               
               
                 atgaaaggcattacattcttcacaccctttttatcatttctatatctctt 
               
               
                   
               
               
                 atgcatcttgtttatgacagaaactgaagctgggtcgagaaatggtgatg 
               
               
                   
               
               
                 gggtctacattgtctacatgggatcagcttcctctgctgcaaacgctaat 
               
               
                   
               
               
                 agagctcaaatactcataaacaccatgtttaaaaggagagcaaacgatct 
               
               
                   
               
               
                 tctccacacatataagcatggcttctcaggttttgcagctcgtttgacag 
               
               
                   
               
               
                 cagaagaggccaaggtcatagccaagaaaccgggagtggtttcagttttt 
               
               
                   
               
               
                 cctgacccacacttccagcttcatacaactcattcatgggactttctcaa 
               
               
                   
               
               
                 gtaccaaacatcagtaaaggtcgattccggtccaccttcatcagcctcag 
               
               
                   
               
               
                 atggatcatatgatagcattgtcggaattcttgacacagggatatggcca 
               
               
                   
               
               
                 gagtcagagagtttcaatgacaaagacatgggtccaattccgtctcggtg 
               
               
                   
               
               
                 gaaaggtacatgcatggaagcaaaggacttcaagtcttccaactgtaaca 
               
               
                   
               
               
                 gaaagatcattggagcaagatactacaaaaatcctgatgatgattcagaa 
               
               
                   
               
               
                 tactataccacaagggatgtcatcggtcacggttctcatgtgtcctccac 
               
               
                   
               
               
                 catagctggatctgccgtggagaatgcttcctactatggtgtagcttccg 
               
               
                   
               
               
                 ggactgcaaagggaggttcacaaaacgctagaatcgctatgtacaaagta 
               
               
                   
               
               
                 tgcaatccagggggatgcactggctcctctatcttagctgctttcgatga 
               
               
                   
               
               
                 tgcaatcgcagatggagttgatgttctatctctgtctcttggagctccag 
               
               
                   
               
               
                 catacgctcgcatcgacttgaacactgatcctattgccattggagcgttt 
               
               
                   
               
               
                 cacgcggtggagcaaggaatcttggtgatctgctctgcgggtaatgatgg 
               
               
                   
               
               
                 acctgatggcggtacagttactaatactgcaccttggataatgaccgttg 
               
               
                   
               
               
                 ctgccaacactattgatagagactttgagtctgatgttgtactaggcggc 
               
               
                   
               
               
                 aataaagtcatcaagggtgaaggtatacacttttcaaacgttagtaaatc 
               
               
                   
               
               
                 tcctgtgtatcctctgattcatggcaagtctgctaagagcgctgatgcat 
               
               
                   
               
               
                 cagaaggatcagccagggcctgtgactctgattctctagatcaagagaag 
               
               
                   
               
               
                 gtaaaagggaagattgtgttatgcgagaacgttggtggatcatattatgc 
               
               
                   
               
               
                 atcatccgctagggacgaggtgaagagcaaaggaggtactggttgcgtct 
               
               
                   
               
               
                 ttgtagatgacagaactagagcagttgctagtgcttatggtagctttcct 
               
               
                   
               
               
                 actaccgtaattgactcaaaggaagcagctgagatcttctcctacctcaa 
               
               
                   
               
               
                 ctcaaccaaagatcctgttgcaacaattcttcccactgcaacagttgaaa 
               
               
                   
               
               
                 agttcacacctgcccctgctgttgcatatttttcttccagaggaccttca 
               
               
                   
               
               
                 agcctcacaagaagcattctcaaacctgacattaccgcaccaggagtctc 
               
               
                   
               
               
                 gatactcgctgcatggactggaaacgactcaagcatttcactggaaggca 
               
               
                   
               
               
                 agccggcttctcagtataacgtcatatcaggaacttccatggcagctcct 
               
               
                   
               
               
                 catgtttcagctgttgcatctctgatcaaatcacagcatcccacatgggg 
               
               
                   
               
               
                 tccatccgcgatcagatcagcaattatgacaacagcgactcaaacaaaca 
               
               
                   
               
               
                 acgacaaaggtcttataacaacagaaactggtgcaacagccacaccttat 
               
               
                   
               
               
                 gactctggagcaggagaactaagctcaacagcatcaatgcaaccaggact 
               
               
                   
               
               
                 agtttacgagactactgaaactgactacctgaactttctctgttactatg 
               
               
                   
               
               
                 gatataacgtaaccacaataaaggctatgtcaaaagcttttccagagaat 
               
               
                   
               
               
                 tttacttgccctgcagattccaacttagacttgatctccaccatcaatta 
               
               
                   
               
               
                 cccgtcaattggaatctctggattcaaaggaaatggtagcaagacagtta 
               
               
                   
               
               
                 caagaacagtgaccaatgttggtgaggacggtgaggcggtttacacagtc 
               
               
                   
               
               
                 agcgtggaaacaccaccagggtttaacattcaagtgacgccagaaaaact 
               
               
                   
               
               
                 ccaatttacaaaagatggtgagaagttgacataccaggtgatagtgtctg 
               
               
                   
               
               
                 ctactgcttcacttaagcaagatgtatttggggctcttacttggtctaat 
               
               
                   
               
               
                 gccaagtacaaggtcagaagcccaattgtaattagtagcgagagtagccg 
               
               
                   
               
               
                 cacaaactga 
               
            
           
         
       
     
     Particularly preferred is a  Nicotiana benthamiana  subtilisin-like serine protease (SBT2) comprising amino acid sequence SEQ ID No. 14, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 115, in particular 1 to 110, of SEQ ID No. 14 represent the signal peptide and propeptide region. The amino acids of the catalytic triad (Asp142, His213, Ser529) are underlined: 
     
       
         
           
               
            
               
                 (SEQ ID No. 14) 
               
               
                 MANHITLCIWLLFFFISIFSLAKSETYIIHMDLSAMPKAFSSHHNWYLTT 
               
               
                   
               
               
                 LSSVSDSSTNHKDFLSSKLVYAYTNAIHGFSASLSPSELEAIKYSPGYVS 
               
               
                   
               
               
                 SIKDISVKIDTTHTSQFLGLNSKSGVWPTSDYGKDIIIGLV D TGIWPESK 
               
               
                   
               
               
                 SYSDDGISEVPSRWKGECESGTEFNSSLCNKKLIGARYFNKGLLANNPNL 
               
               
                   
               
               
                 NISMNSSRDTDG H GTHTSSTAAGSYVEGASYFGYATGTAIGIAPKAHVAM 
               
               
                   
               
               
                 YKALWEEGVYLSDVLAAIDQATTDGVDVLSLSLGIDAIPLHEDPVAIAAF 
               
               
                   
               
               
                 AALEKGIFVSTSAGNEGPYYETLHNGTPWVLTVAAGTVDREFIGTLTLGN 
               
               
                   
               
               
                 GVSVPGLSLYPGNSSSSESSLVYVECQDDKELQKNAHKFVVCLDKNDSVG 
               
               
                   
               
               
                 EHVYNVRNSKVAGAVFITNTTDLEFYLQSEFPAVFLNLQEGDKVLEYIKS 
               
               
                   
               
               
                 NSAPKGKLEFQVTHIGAKPAPKVATYSSRGPSPSCPSILKPDLMAPGALI 
               
               
                   
               
               
                 LASWPQQSPVTDVTSGKLFSNFNIISGT S MSCPHASGVAALLKAAHPEWS 
               
               
                   
               
               
                 PAAIRSAMMTTSTALDNTQSPIRDIGNKNAAATPLAMGAGHIDPNKALDP 
               
               
                   
               
               
                 GLIYDATPQDYVNLLCALNFTSKQIKTITRSSSYTCSNPSLDLNYPSFIG 
               
               
                   
               
               
                 FFNGNSSESDPKRIQEFKRTVTNLQDGTSIYTANFTPMGKFKVSVVPEKL 
               
               
                   
               
               
                 VFKEKYEKLSYKLRIEGPIVMDDNVVYGSLSWVETGGNYVVRSPIVATSI 
               
               
                   
               
               
                 KVDPLTGHN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Nicotiana benthamiana  subtilisin-like serine protease may comprise SEQ ID No. 15, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 345, in particular 1 to 330, of SEQ ID No. 15 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 15) 
               
               
                 atggcaaatcatattaccttgtgtatttggttgcttttcttctttatttc 
               
               
                   
               
               
                 tatattttcactagcaaagtcagaaacatatatcattcatatggatttgt 
               
               
                   
               
               
                 cagccatgccaaaagctttttctagccatcataattggtacttgacaaca 
               
               
                   
               
               
                 ctttcttctgtatcagacagcagtacaaatcacaaagacttcttgtcctc 
               
               
                   
               
               
                 aaaactagtctatgcttatactaatgctatacatggttttagtgcaagtc 
               
               
                   
               
               
                 tctctccttctgaacttgaagccataaaatattctccaggttatgtttct 
               
               
                   
               
               
                 tcaattaaggatatttcagttaaaattgacacaactcacacatcccagtt 
               
               
                   
               
               
                 tcttggcctaaactctaagtctggtgtatggccaacgtccgactatggga 
               
               
                   
               
               
                 aagatatcataattggcttagttgatactggaatatggcctgagagtaaa 
               
               
                   
               
               
                 agctatagtgatgatgggattagtgaagtaccatcaagatggaaaggaga 
               
               
                   
               
               
                 atgtgaaagtggtactgagttcaattcctctttgtgtaacaagaagctca 
               
               
                   
               
               
                 ttggcgctcgttacttcaataaaggcctacttgccaacaatccaaatctt 
               
               
                   
               
               
                 aatatttcaatgaattcttctagagataccgatggacatggaactcacac 
               
               
                   
               
               
                 ttcttctacagctgcgggaagttatgttgagggtgcatcttattttggct 
               
               
                   
               
               
                 atgccaccggtactgctattggcatagcgccaaaggctcatgtggctatg 
               
               
                   
               
               
                 tacaaggctctatgggaagaaggtgtatacttgtctgatgttcttgctgc 
               
               
                   
               
               
                 aattgatcaagcaattacagatggtgtggatgtcttatccttgtcgttag 
               
               
                   
               
               
                 gcatagacgcgattccactacacgaagatcctgtggcaattgccgcattt 
               
               
                   
               
               
                 gctgcattggagaaaggtatatttgtttccacctctgcaggaaatgaagg 
               
               
                   
               
               
                 gccttattatgagactttgcacaatggaacaccttgggtgttaactgttg 
               
               
                   
               
               
                 cagctggcacagttgaccgcgaatttattggaacattaactcttggaaat 
               
               
                   
               
               
                 ggagtttcagtccctggtttatcgctataccctgggaattctagttcaag 
               
               
                   
               
               
                 cgaaagctcccttgtctatgtcgaatgccaagatgacaaggaactgcaga 
               
               
                   
               
               
                 aaaatgcacacaaatttgttgtctgtctcgacaagaatgattcggttggt 
               
               
                   
               
               
                 gagcatgtgtacaatgtaagaaattcaaaagttgctggggctgtctttat 
               
               
                   
               
               
                 aactaatacaactgacttggaattctacctccaaagcgaattcccggctg 
               
               
                   
               
               
                 tgttcttgaacttacaagagggtgataaagttctagagtacattaagagc 
               
               
                   
               
               
                 aactctgcacctaaaggaaaacttgaattccaagttacacatattggtgc 
               
               
                   
               
               
                 taaaccagcgccaaaagttgctacctatagctcaagaggaccgtcaccga 
               
               
                   
               
               
                 gttgtccaagtatcctcaaacctgatctcatggctcctggtgccttaata 
               
               
                   
               
               
                 cttgcttcatggccacaacaatcaccagttactgatgttacctcaggaaa 
               
               
                   
               
               
                 actttttagtaacttcaatattatatctggtacatcaatgtcatgtccac 
               
               
                   
               
               
                 atgcttctggtgtagcagcacttctaaaagctgcacaccctgaatggagc 
               
               
                   
               
               
                 cctgcagccatccgatctgccatgatgaccacttccactgcgttggacaa 
               
               
                   
               
               
                 cacacagagccccatccgagacataggtaacaagaatgcggctgctactc 
               
               
                   
               
               
                 ctctagccatgggagctggccatatcgatccaaacaaggcgttagatcct 
               
               
                   
               
               
                 ggacttatctatgatgcaacaccacaagattatgtcaatctcctctgtgc 
               
               
                   
               
               
                 tctgaacttcacatccaaacaaataaaaaccatcacaagatcctcatctt 
               
               
                   
               
               
                 atacttgctccaacccatcattggacttaaactatccatccttcattggc 
               
               
                   
               
               
                 tttttcaatggtaacagcagcgagtcggatcctaaaaggattcaagaatt 
               
               
                   
               
               
                 taaaagaacagtgacaaacttacaagatggtacatcaatatatacagcaa 
               
               
                   
               
               
                 acttcactccaatgggtaaatttaaagttagtgttgtacctgaaaagttg 
               
               
                   
               
               
                 gttttcaaagagaagtatgaaaagctgagctacaagcttagaatagaagg 
               
               
                   
               
               
                 tccaatagttatggatgataatgtggtttatggttctttgagctgggtag 
               
               
                   
               
               
                 aaactggaggtaactatgtggttagaagtccaattgttgccacaagcata 
               
               
                   
               
               
                 aaagtggatcctttgacaggacacaactga 
               
            
           
         
       
     
     Particularly preferred is a  Nicotiana tabacum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 16, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 115, in particular 1 to 110, of SEQ ID No. 16 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 16) 
               
               
                 MANHITLCIWLLFFFISIISLAKSETYIIHMDFSAMPKAFSSHHNWYLTT 
               
               
                   
               
               
                 LSSVSDSSTNYKDFLSSKLVYSYTNAIHGFSASLSPSELEAIKNSPGYVS 
               
               
                   
               
               
                 SIKDISVKIDTTHTSQFLGLNSESGVWPTSEYGKDIIIGLVDTGIWSESK 
               
               
                   
               
               
                 SYSDDGISEVPSRWKGECESGTEFNSSLCNKKLIGARYFNKGLLANNPNL 
               
               
                   
               
               
                 NISMNSARDTDGHGTHTSSTAAGSYVEGASYFGYATGTAIGIAPKAHVAM 
               
               
                   
               
               
                 YKALWEEGVYLSDVLAAIDQAITDGVDVLSLSLGIDAIPLHEDPVAIAAF 
               
               
                   
               
               
                 AALEKGIFVSTSAGNEGPYYETLHNGTPWVLTVAAGTVDREFIGTLTLGN 
               
               
                   
               
               
                 GVSVTGLSLYPGNSSSSESSIVYVECQDDKELQKNAHKFVVCLDKNDSVG 
               
               
                   
               
               
                 EHVYNVRNSKVAGAVFITNTTDLEFYLQSEFPAVFLNLQEGDKVLEYIKS 
               
               
                   
               
               
                 NSAPKGKLEFQVTHIGAKRAPEVATYSSRGPSPSCPSILKPDLMAPGALI 
               
               
                   
               
               
                 LASWPQQSPVTDVTSGKLFSNFNIISGTSMSCPHASGVAALLKGAHPEWS 
               
               
                   
               
               
                 PAAIRSAMMTTSSALDNTQSPIRDIGNVELRNAAATPLAMGAGHIDPNKA 
               
               
                   
               
               
                 LDPGLIYDATPQDYVNLLCALNFTSKQIKIITRSSSYTCSNPSLDLNYPS 
               
               
                   
               
               
                 FIGFFNGNSRESDPKRIQEFKRTVTNLQDGTSVYTANLIPMGKFKVSVVP 
               
               
                   
               
               
                 EKLVFKEKYEKLSYKLRIEGPIVMDDNVVYGSLSWVETGGKYVVRSPIVA 
               
               
                   
               
               
                 TSIKVDPLTGHN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Nicotiana tabacum  subtilisin-like serine protease may comprise SEQ ID No. 17, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 345, in particular 1 to 330, of SEQ ID No. 17 encode the signal peptide and the propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 17) 
               
               
                 atggcaaatcatattaccttgtgtatttggttgcttttcttctttatttc 
               
               
                   
               
               
                 tataatttcactagcaaagtcagaaacatatatcattcatatggattttt 
               
               
                   
               
               
                 cagccatgccaaaagctttttctagccatcataattggtacttgacaaca 
               
               
                   
               
               
                 ctttcttctgtatcagacagcagtacaaattacaaagacttcttgtcctc 
               
               
                   
               
               
                 aaaactagtctattcttatactaatgccatacatggttttagtgcaagtc 
               
               
                   
               
               
                 tttctccttctgaacttgaagccataaaaaattctccaggctatgtttct 
               
               
                   
               
               
                 tcaattaaggatatttcagttaaaattgacacaactcacacatcccaatt 
               
               
                   
               
               
                 tcttggcctaaactctgagtctggtgtatggccaacgtccgagtatggta 
               
               
                   
               
               
                 aagatatcataattggcttagttgatactggaatatggtcggagagtaaa 
               
               
                   
               
               
                 agctatagtgatgatgggattagtgaagtaccatcaagatggaaaggaga 
               
               
                   
               
               
                 atgtgaaagtggtactgagttcaattcctctttgtgtaacaagaaactca 
               
               
                   
               
               
                 ttggcgctcgttacttcaataaaggcctacttgccaacaatccaaatctt 
               
               
                   
               
               
                 aacatttcaatgaattctgctagagataccgatggacatggaactcacac 
               
               
                   
               
               
                 ttcttctacagctgcgggaagttatgtcgagggtgcatcttattttggct 
               
               
                   
               
               
                 atgccactggcactgctataggcatagcaccaaaggctcatgtggctatg 
               
               
                   
               
               
                 tacaaggctctatgggaagaaggtgtatacttgtctgatgttcttgctgc 
               
               
                   
               
               
                 aattgatcaagcaattacagatggtgtggatgtcttatccttgtctttag 
               
               
                   
               
               
                 gcatagacgcgattccactacacgaagatcctgtggcaattgccgcattt 
               
               
                   
               
               
                 gctgcattggagaaaggtatatttgtttccacctctgcaggaaatgaagg 
               
               
                   
               
               
                 gccttattatgagactttgcacaatggaacaccttgggtgctaactgttg 
               
               
                   
               
               
                 cagctggcacagttgaccgcgaatttattggaacattaactcttggaaat 
               
               
                   
               
               
                 ggagtttcagtcactggcttatcgctataccctgggaattctagttcaag 
               
               
                   
               
               
                 cgaaagctccattgtctatgtcgaatgccaagatgacaaggaactacaga 
               
               
                   
               
               
                 aaaatgcacataaatttgttgtctgtctcgacaagaatgattcggtcggt 
               
               
                   
               
               
                 gagcatgtgtacaatgtaagaaattcaaaagttgctggggctgtctttat 
               
               
                   
               
               
                 aactaatacaactgacttggaattctacctccaaagcgaattcccggctg 
               
               
                   
               
               
                 tgttcttgaacttacaagagggtgataaagttctagagtacattaagagc 
               
               
                   
               
               
                 aactctgcacctaaaggaaaacttgaattccaagtgacacatattggtgc 
               
               
                   
               
               
                 taaacgagcaccagaagttgctacctatagctcaagaggaccgtcaccga 
               
               
                   
               
               
                 gttgtccaagtatcctcaagcctgatctcatggctcctggtgccttaata 
               
               
                   
               
               
                 cttgcttcatggccacagcaatcaccagttactgatgttacctcaggaaa 
               
               
                   
               
               
                 gctttttagtaacttcaatattatatctggtacatcaatgtcatgtccac 
               
               
                   
               
               
                 atgcttctggtgtagcagcacttctaaaaggcgcacaccctgaatggagc 
               
               
                   
               
               
                 cccgcagccatccgatctgccatgatgaccacttccagtgcgttggacaa 
               
               
                   
               
               
                 cacacagagccccatccgagacataggtaatgttgaactcaggaatgctg 
               
               
                   
               
               
                 ctgctactcctctagccatgggagctggccatatcgatccaaacaaggca 
               
               
                   
               
               
                 ttagatcctggacttatctatgatgcgacaccacaagattatgtcaatct 
               
               
                   
               
               
                 tctctgtgctctgaacttcacatccaaacaaataaaaatcatcacaagat 
               
               
                   
               
               
                 cctcatcttatacttgctccaacccatcattggacttaaactatccatcc 
               
               
                   
               
               
                 ttcattggctttttcaatgggaacagcagagagtcggatcctaaaaggat 
               
               
                   
               
               
                 tcaagaattcaaaagaacagtgacaaacttacaagatggtacatcagtat 
               
               
                   
               
               
                 atacagcaaatctcactccaatgggtaaatttaaagttagtgttgtacct 
               
               
                   
               
               
                 gaaaagttggttttcaaagagaagtatgaaaagctgagctacaagcttag 
               
               
                   
               
               
                 aatagaaggtccaatagttatggatgataatgtggtttatggttctttga 
               
               
                   
               
               
                 gctgggtagaaactggaggtaaatatgtggttagaagtccaattgttgcc 
               
               
                   
               
               
                 acaagcataaaagtggatcctttgacaggacacaactga 
               
            
           
         
       
     
     Particularly preferred is a  Nicotiana tabacum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 18, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 115, in particular 1 to 110, of SEQ ID No. 18 represent the signal peptide and propeptide region: 
     
       
         
           
               
            
               
                 (SEQ ID No. 18) 
               
               
                 MASHITLCIWLLFFFISIISLAKPETYIIHMDLSAMPKAFASHHNWYLTT 
               
               
                   
               
               
                 LASLSDSSTNHKEFLSSKLVYAYTNAINGFSASLSPSEFEAIKNSPGYVS 
               
               
                   
               
               
                 SIKDMSVKIDTTHTSQFLGLNSESGVWPTSDYGKDIIIGLVDTGIWPESK 
               
               
                   
               
               
                 SYSDYGISEVPSRWKGECESGIEFNSSLCNKKIIGARYFNKGLLANNPNL 
               
               
                   
               
               
                 NISMNSARDTDGHGTHTSSTAAGSYVEGASYFGYATGTAIGIAPKAHVAM 
               
               
                   
               
               
                 YKALWEEGVYLSDVLAAIDQAITDGVDVLSLSLGIDAIPLHEDPVAIAAF 
               
               
                   
               
               
                 AALEKGIFVSTSAGNEGPYYETLHNGTPWVLTVAAGTVDREFIGALTLGN 
               
               
                   
               
               
                 GVSVTGLSLYPGNSSSSESSIVYVECQDDKELQKSAHNIVVCLDKNDSVS 
               
               
                   
               
               
                 EHVYNVRNSKVAGAVFITNITDLEFYLQSEFPAVFLNLQEGDKVLEYIKS 
               
               
                   
               
               
                 NSAPKGKLEFRVTHIGAKPAPKVATYSSRGPSPSCPSILKPDLMAPGALI 
               
               
                   
               
               
                 LASWPQQSPVTDVTSGKLFSNFNIISGTSMSCPHASGVAALLKAAHPEWS 
               
               
                   
               
               
                 PAAIRSAMMTTSNAMDNTQSPIRDIGSKNAAATPLAMGAGHIDPNKALDP 
               
               
                   
               
               
                 GLIYDATPQDYVNLLCALNFTSKQIKTITRSSSYTCSNPSLDLNYPSFIG 
               
               
                   
               
               
                 FFNGNSSESDPRRIQEFQRTVTNIGDGMSVYTAKLTTMGKFKVNLVPEKL 
               
               
                   
               
               
                 VFKEKYEKLSYKLRIEGPLVMDDIVVYGSLSWVETEGKYVVRSPIVATSI 
               
               
                   
               
               
                 KVDPLTGHN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Nicotiana tabacum  subtilisin-like serine protease may comprise SEQ ID No. 19, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 345, in particular 1 to 330, of SEQ ID No. 19 encode the signal peptide and the propeptide region: 
     
       
         
           
               
               
            
               
                 (SEQ ID No. 19) 
                   
               
               
                 atggcaagtcatattaccttgtgtatttggttgcttttcttctttatttctataatt 
                   
               
               
                 tcactagcaaagccagaaacatatatcattcatatggatttgtcagccatgccaaaa 
               
               
                 gcttttgctagccatcataattggtacttgacaacacttgcttctttatcagacagt 
               
               
                 agtacaaatcacaaagaattcttgtcctcaaaactagtctatgcttatactaatgcc 
               
               
                 atcaatggttttagtgcaagtctttctccttctgaatttgaagccataaaaaattct 
               
               
                 ccaggttatgtttcttcaattaaggatatgtcagttaaaattgacacaactcacaca 
               
               
                 tcccaattccttggcctaaactctgagtctggtgtatggccaacgtccgactatggt 
               
               
                 aaagatatcataattggcttagttgatactggaatatggccagagagtaaaagctat 
               
               
                 agtgattatgggattagtgaagtaccatcaagatggaaaggagaatgtgaaagtggc 
               
               
                 attgagttcaattcctctttgtgtaacaagaaaatcattggcgctcgttacttcaat 
               
               
                 aaaggcctacttgccaacaatccaaatcttaacatttcaatgaattctgctagagat 
               
               
                 acagatggacatggaactcacacttcttccacagctgcgggaagttatgtcgagggt 
               
               
                 gcatcttattttggctatgccaccggcactgctattggcatagcaccaaaggctcat 
               
               
                 gtggctatgtacaaggctctatgggaagaaggtgtatacttgtctgatgttcttgct 
               
               
                 gcaattgatcaagcaattacagatggtgtagatgttttatccttgtcattaggcata 
               
               
                 gacgcgattccactacacgaagatcctgtggcaattgccgcatttgctgcattggag 
               
               
                 aaaggtatatttgtttccacctctgcaggaaatgaagggccttattatgagactttg 
               
               
                 cacaatggaacaccttgggtgctaactgttgcagctggcacagttgaccgcgaattt 
               
               
                 attggcgcattaactcttggaaatggagtttcagtcactggcttatcgctctaccct 
               
               
                 gggaattctagttcaagtgaaagctccattgtctatgttgaatgccaagatgacaag 
               
               
                 gaactgcaaaaaagtgcacacaatattgttgtctgccttgacaagaatgattcggtc 
               
               
                 agtgagcatgtgtacaatgtgagaaattcaaaagttgctggggctgtcttcataact 
               
               
                 aatataactgatttggaattctacctccaaagcgaattcccggctgtgttcttgaac 
               
               
                 ttacaagagggtgataaagttctagagtacattaagagcaactctgcacctaaagga 
               
               
                 aaacttgaattccgagtgacacatattggtgctaaaccagcaccaaaagttgctacc 
               
               
                 tatagctcaagaggaccgtcaccgagctgtccaagtatcctcaagcctgatctcatg 
               
               
                 gctcctggtgccttaatactagcttcatggccacaacaatcaccagtgactgatgtt 
               
               
                 acctcaggaaaactttttagtaacttcaatattatatctggtacatcaatgtcatgt 
               
               
                 ccacatgcttctggtgtagcagcacttctaaaagccgcacaccctgaatggagccct 
               
               
                 gcagccatccgatctgccatgatgaccacttccaatgcgatggacaacacacaaagt 
               
               
                 cccatccgagacataggtagtaagaatgctgctgctactcctctagccatgggagct 
               
               
                 ggccatatcgatccaaacaaggcactagatcctggacttatctatgatgcgacacca 
               
               
                 caagattatgtcaatcttctctgtgctctgaacttcacatccaaacaaataaaaacc 
               
               
                 atcacaagatcctcatcttatacttgctccaacccatcattggacttaaactatcca 
               
               
                 tctttcattggatttttcaatgggaacagcagcgagtcggatcctagaaggatacaa 
               
               
                 gaattccagaggaccgtgactaatattggagatggtatgtcagtatacacagcaaaa 
               
               
                 ttgaccacaatgggtaaatttaaagttaatcttgtacctgaaaagttggttttcaaa 
               
               
                 gagaagtatgaaaagttgagctacaagctaagaatagaaggtccattagttatggat 
               
               
                 gatattgtggtttatggttctttgagctgggtagaaactgaaggtaaatatgtggtt 
               
               
                 agaagtccaattgttgccacaagcataaaagtagatcctttgacaggacacaactga 
               
            
           
         
       
     
     Particularly preferred is a  Solanum lycopersicum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 20, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 102, of SEQ ID No. 20 represent the signal peptide and propeptide region: 
     
       
         
           
               
               
            
               
                 (SEQ ID No. 20) 
                   
               
               
                 MANYIALCIWLLSIIQLAKSETYIIHMDLSAMPKAFSSHYNWYLTTLFSVSDSKDLL 
                   
               
               
                 SSKLVYTYTNAINGFSASLSPSEIEAIKNSPGYVSSIKDMSVKVDTTHTSQFLGLNS 
               
               
                 ESGVWPKSDYGKDVIVGLVDTGIWPESRSYSDDGMNEVPSRWKGECESGTQFNTSLC 
               
               
                 NKKLIGARYFNKGLLANNPNLTISMDSARDTDGHGTHTSSTAAGSRVEGASFFGYAA 
               
               
                 GTATGVAPKAHVAMYKALWEEGVFLSDILAAIDQATADGVDVLSLSLGIDALPLYED 
               
               
                 PVAIAAFAALEKGIFVSTSAGNEGPFLETLHNGTPWVLTVAAGTVDREFIGTVTLGN 
               
               
                 GVSVTGLSLYPGNSSSSESSISFVDCQDDKELQKNAHRIVVCIDNNDSVSEDVYNVR 
               
               
                 NSKVSGAVFITNSTDLEFYLQSEFPAVFLNIQEGDKVLEYVRSDSAPNAKLEFQVTR 
               
               
                 IGAKPAPKVASYSSRGPSPSCPTILKPDLMGPGALILASWPQQTPVTEVTSGKLYSN 
               
               
                 FNIISGTSMSCPHASGVAALLKSAHPEWSPAAIRSAMMTTAYVLDNTQSPIQDVGLK 
               
               
                 NGVATPLAMGAGHIDPNKALDPGLIYDATPQDYVNHLCGLNFTSKQIQTITRSSTYT 
               
               
                 CSNPSLDLNYPSFIGYFNRNSSDSDPKRIQEFKRTVTNLQDGTSVYTAKLTPMGKFK 
               
               
                 VSVVPNKLTFKEKYEKQSYKLRIEGPIIMDDIVVDGSLSWMETRGKYIVKSPIVATS 
               
               
                 IRVDPLRGHN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Solanum lycopersicum  subtilisin-like serine protease may comprise SEQ ID No. 21, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 306, of SEQ ID No. 21 encode the signal peptide and the propeptide region: 
     
       
         
           
               
               
            
               
                 (SEQ ID No. 21) 
                   
               
               
                 atggcaaattatattgccttgtgtatttggttgctttctataattcaattggcaaag 
                   
               
               
                 tcagaaacttatatcattcatatggatttgtcagccatgccaaaagctttttctagc 
               
               
                 cattataattggtacttgactacacttttttcggtgtcagatagcaaagacttgttg 
               
               
                 tcctctaaactagtttatacttatactaatgccatcaatggtttcagtgcaagtctt 
               
               
                 tctccttctgagatagaagctattaagaattctccgggttatgtttcttcgattaag 
               
               
                 gatatgtcggttaaagttgacacaacccacacatctcaattccttggccttaactct 
               
               
                 gagtctggtgtatggccaaagtcggattatggcaaagatgttatagttggattagtt 
               
               
                 gacactgggatatggccagagagtagaagttatagtgatgatgggatgaatgaagta 
               
               
                 ccatcaagatggaaaggagaatgtgaaagtggaactcagttcaatacctctttgtgc 
               
               
                 aataagaaactcattggcgctcgttacttcaataaaggcctacttgctaacaacccg 
               
               
                 aatcttaccatttcgatggattctgctcgtgatacggatggacatgggactcacact 
               
               
                 tcttccacggctgctggaagtcgtgtagagggtgcatctttttttggatatgctgct 
               
               
                 ggaactgctacaggtgtagcaccaaaggctcatgtggccatgtacaaggctctatgg 
               
               
                 gaagaaggtgtattcttgtctgatattcttgcagcaattgatcaagcaattgcagat 
               
               
                 ggtgtagatgtattgtccttgtcattaggcattgatgcgcttcctttatacgaagat 
               
               
                 cctgttgcaattgccgcatttgctgcactggagaaaggcatatttgtttctacatct 
               
               
                 gcaggaaatgaagggccttttttggaaactttgcacaatggaacgccttgggtgctc 
               
               
                 actgttgctgctggcacagttgaccgggagtttattggcacagtaacacttggaaat 
               
               
                 ggagtttcggtcactggattatcgctctaccctgggaactctagttcaagtgaaagc 
               
               
                 tccattagcttcgttgattgccaagatgataaggaactgcagaaaaatgcacacaga 
               
               
                 atagtggtctgcattgacaataatgattcagttagcgaggacgtctacaatgtaaga 
               
               
                 aattcaaaagtttctggtgcagtcttcataactaattcaactgacttggaattctat 
               
               
                 ctccaaagtgaatttcccgcggtgtttttgaacattcaagagggtgataaagttctt 
               
               
                 gagtacgttaggagtgactctgcacctaacgcaaagcttgaattccaagtgacgcgt 
               
               
                 attggtgctaaaccagcaccaaaagttgctagctatagctcaagaggaccatcacca 
               
               
                 agctgtcctacaattctaaagcctgaccttatgggtcctggtgcattaatacttgct 
               
               
                 tcatggccacaacaaacaccagtaactgaagttacctcgggaaaactttatagtaac 
               
               
                 ttcaacattatatcaggcacatcaatgtcttgtccacatgcttctggtgtagcagca 
               
               
                 cttctaaaaagtgcacaccctgaatggagccctgctgctatccgatccgccatgatg 
               
               
                 accacagcctatgtattggacaacacacaaagccccatccaagacgtaggtctgaag 
               
               
                 aatggtgttgctactcctctagctatgggagctggccatatcgatccaaacaaagcg 
               
               
                 ttggatcccggactcatctatgatgcaacaccacaagattatgttaaccacctctgt 
               
               
                 ggtttgaacttcacatccaaacaaatacaaaccatcacaagatcctcaacttacact 
               
               
                 tgctccaacccatcattagacttgaactatccatcattcattggctatttcaaccgg 
               
               
                 aatagcagcgattcggatcctaaaaggattcaagaattcaaaagaacagtgactaac 
               
               
                 ttacaagatggtacatcagtatacacagcaaagctcactccaatgggtaaatttaaa 
               
               
                 gttagtgttgtacctaataagttgactttcaaagaaaagtatgaaaaacaaagctat 
               
               
                 aagctaagaatagaaggtccaataattatggatgatattgtggttgatggttcattg 
               
               
                 agctggatggaaactagaggaaaatacatagttaaaagtccaattgttgcaacaagt 
               
               
                 ataagagtggatcctttgagaggacataactga 
               
            
           
         
       
     
     Particularly preferred is a  Solanum tuberosum  subtilisin-like serine protease comprising amino acid sequence SEQ ID No. 22, whereby amino acid residues 1 to 150, preferably 1 to 140, more preferably 1 to 130, more preferably 1 to 120, more preferably 1 to 110, in particular 1 to 102, of SEQ ID No. 22 represent the signal peptide and propeptide region: 
     
       
         
           
               
               
            
               
                 (SEQ ID No. 22) 
                   
               
               
                 MANHIALCIWLLSIIQLAKSETYIIHMDLSAMPKAFSSHHNWYLTTLSSVSDSKDLL 
                   
               
               
                 SSKLVYTYTNAINGFSASLSPSEIEAIKNSPGYVSSIKDMSVKVDTTHTSQFLGLNS 
               
               
                 ESGVWPKSDYGKDVIVGLVDTGIWPESRSYSDDGMNEVPSRWKGECESGTQFNSSLC 
               
               
                 NKKLIGARYFNKGLLANNPNLTISMDSSRDTDGHGTHTSSTAAGSRVEGASFFGYAA 
               
               
                 GTATGVAPKAHVAMYKALWEEGVFLSDILAAIDQAIEDGVDVLSLSLGIDALPLYED 
               
               
                 PVAIAAFAALEKGIFVSTSAGNEGPFLETLHNGTPWVLTVAAGTVDREFIGTLTLGN 
               
               
                 GVSVTGLSLYPGNSSSSERSISYVDCQDDKELQKNAHKIVVCIDKSDSVSEDVYNVR 
               
               
                 NSKVSGAVFITNSTDLEFYLQSEFPAVFLNIQEGDKVLEYVRSEAAPNAKLEFQVTR 
               
               
                 IGAKPAPKVASYSSRGPSPSCPIILKPDLMGPGALILASWPQQTPVTEVTSGKLYSN 
               
               
                 FNIISGTSMSCPHASGVAALLKSAHPEWSPAAIRSAMMTTAYVLDNTQSPIQDIGLK 
               
               
                 NGVATPLAMGAGHIDPNKALDPGLIYDATPQDYVNLLCALNFTSKQIQTITRSSTYT 
               
               
                 CSNPSLDLNYPSFIGYFNRNSSDSDPKRIQEFIRTVTNLQDGTSVYTAKITPMGKFK 
               
               
                 VSVVPNKLIFKEKYEKQSYKLRIEGPIIMDDIVVDGSLSWMETRGKYIVKSPIVATS 
               
               
                 IRVDPLRGHN 
               
            
           
         
       
     
     A nucleic acid sequence encoding the  Solanum tuberosum  subtilisin-like serine protease may comprise SEQ ID No. 23, whereby nucleotide residues 1 to 450, preferably 1 to 420, more preferably 1 to 390, more preferably 1 to 360, more preferably 1 to 330, in particular 1 to 306, of SEQ ID No. 23 encode the signal peptide and the propeptide region: 
     
       
         
           
               
               
            
               
                 (SEQ ID No. 23) 
                   
               
               
                 atggcaaatcatattgccttgtgtatttggttgctttctataattcaattggcaaag 
                   
               
               
                 tcagaaacttatatcattcatatggatttgtcagccatgccaaaagctttttctagc 
               
               
                 catcataattggtacttgactacactttcttctgtatcagatagcaaagacttgttg 
               
               
                 tcctctaaactagtttatacttatactaatgccatcaatggtttcagtgcaagtctt 
               
               
                 tctccttctgagatagaagctattaagaattctcccggctatgtttcttcgattaag 
               
               
                 gatatgtcggttaaagttgacacaactcacacatctcaattccttggccttaactct 
               
               
                 gagtctggtgtatggccaaagtctgattatggcaaagatgtcatagttggattagtt 
               
               
                 gacactgggatatggccagagagtagaagttatagtgatgatgggatgaatgaagta 
               
               
                 ccatcaagatggaaaggagaatgtgaaagtggaactcagttcaattcctctttgtgc 
               
               
                 aataagaaactcattggcgctcgttacttcaataaaggcctacttgctaacaacccg 
               
               
                 aatcttaccatttcgatggattcttctcgtgatacggatggacatgggactcatact 
               
               
                 tcttccacggctgctggaagtcgtgtagagggtgcatctttttttggctatgccgct 
               
               
                 ggaacagctacaggtgtagcaccaaaggctcatgtggccatgtacaaggctctatgg 
               
               
                 gaagaaggtgtattcttgtctgatattcttgcagcaattgatcaagcaattgaagat 
               
               
                 ggtgtagatgtattgtcgttgtcattaggcattgacgcgcttccattatacgaagat 
               
               
                 cctgttgcaattgctgcatttgctgcactggagaaaggcatatttgtttctacatct 
               
               
                 gcaggaaatgaagggccatttttggaaactttgcacaatggaacaccttgggtgctc 
               
               
                 actgttgctgctggcacggttgaccgtgagtttattggcacactaacacttggaaat 
               
               
                 ggagtttcggtcactggattatcgctctaccctgggaattctagttcaagtgaacgc 
               
               
                 tccattagctatgttgattgccaagatgataaggaactgcagaaaaatgcacacaaa 
               
               
                 atagtggtctgcattgacaagagtgattcagttagcgaagacgtctacaatgtaaga 
               
               
                 aattcaaaagtttctggtgcagtcttcataactaattcaactgacttggaattctac 
               
               
                 ctccaaagtgaatttcctgcagtgtttttgaacattcaagagggtgataaagttctt 
               
               
                 gagtatgttaggagtgaggctgcacctaacgcaaagcttgaattccaagtgacgcgt 
               
               
                 attggtgctaaaccagcaccaaaagttgctagctatagctcaagaggaccatcacca 
               
               
                 agttgtcctataattctcaagcctgacctcatgggtcctggtgccttaatacttgct 
               
               
                 tcatggccacaacaaacaccagtaactgaagttacctcaggaaaactttatagtaac 
               
               
                 ttcaacattatatcaggcacatcaatgtcttgtccacatgcttctggtgtagcagca 
               
               
                 cttctaaaaagtgcacaccctgaatggagccctgctgctatccgatccgccatgatg 
               
               
                 accacagcctatgtattggacaacacacaaagccccatccaagacataggtttgaag 
               
               
                 aatggtgttgctactcctctagctatgggagctggccatatcgatccaaacaaggcg 
               
               
                 ttggatcccggactcatctatgatgcaacaccacaagattatgttaatctcctttgt 
               
               
                 gctttgaacttcacatccaaacaaatacaaaccatcacaagatcctcaacttacact 
               
               
                 tgctccaacccatcattagacttgaactatccatctttcattggctatttcaaccgg 
               
               
                 aacagcagcgattcagatcctaaaaggattcaagaattcataagaacagtgacaaac 
               
               
                 ttacaagatggtacatcagtatacacagcaaagatcactccaatgggtaaatttaaa 
               
               
                 gttagtgttgtacctaataagttgattttcaaagaaaagtatgaaaagcaaagctac 
               
               
                 aagctaagaatagaaggtccaataattatggatgatattgtggttgatggttccttg 
               
               
                 agttggatggaaactagaggaaaatacatagtcaaaagtccaattgttgcaacaagt 
               
               
                 ataagagtggatcctttgagaggacataactga 
               
            
           
         
       
     
     According to a preferred embodiment of the present invention the proteolytic activity of the at least one serine protease in the genetically modified plant or plant cell is at least 10%, preferably at least 25%, more preferably at least 50%, more preferably at least 70%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95%, in particular 100%, reduced compared to its activity in the wild-type plant or plant cell. A preferred method for determining the proteolytic activity is for example the method described by Twining, 1984, Anal. Biochem. 143, 30-34. 
     According to a particularly preferred embodiment of the present invention said at least one serine protease of the wild-type plant or plant cell is mutated in the genetically modified plant or plant cell at at least one position of its amino acid sequence to reduce its proteolytic activity. 
     The proteolytic activity of a protease can be influenced by introducing one or more mutations within the amino acid sequence of said protease. The mutations may involve substitution, deletion or introduction of at least one amino acid residue within the amino sequence of the protease. The effect of the introduction of the at least one mutation can be determined by using an assay for determining the proteolytic activity in the mutated variant and comparing these results with the results of a proteolytic activity assay with a non-mutated version of the same protease. 
     Serine proteases require for their enzymatic activity a catalytic triad. In order to reduce the proteolytic activity of such proteases one or more amino acid residues of this catalytic triad may be substituted or deleted. Hence, the serine protease activity is preferably reduced by at least one amino acid substitution in the catalytic triad of a serine protease motif. 
     The proteolytic activity of the serine proteases of the present invention can be preferably reduced by mutating at least one amino acid residue (substitution or deletion) within the catalytically active fragment of said serine proteases. 
     “Catalytically active fragment” or “enzymatically active fragment”, as used herein, refers to a polypeptide fragment that contains the catalytically active domain of a protease sufficient to exhibit activity. A catalytically active fragment is the portion of a protease that, under appropriate conditions, can exhibit catalytic activity and is able to cleave a bond in a peptide, polypeptide or protein. Typically, a catalytically active fragment is a contiguous sequence of amino acid residues of a protease that contains the catalytic domain and required portions for recognizing the substrate to be cleaved. A preferred enzymatically/catalytically active fragment of a protease lacks amino acid residues 1 to 200, preferably 5 to 190, more preferably 10 to 180, more preferably 15 to 170, more preferably 15 to 160, more preferably 20 to 150, more preferably 25 to 125, more preferably 1 to 115, even more preferably 1 to 102-110 of a wild-type serine protease according to the present invention (e.g. SEQ ID No. 2, 4, 6, 8, 10, 14, 16, 18, 20 or 22). 
     According to a preferred embodiment of the present invention the catalytically active fragment of a subtilisin-like serine protease comprises or consists of an amino acid sequence selected from the group consisting of amino acid residues 101 to 770, preferably 106 to 770, more preferably 108 to 770, more preferably 109 to 770, more preferably 111 to 770, more preferably 112 to 770, more preferably 113 to 770, more preferably 116 to 770, more preferably 121 to 770, in particular 110 to 770, of SEQ ID No. 2; amino acid residues 101 to 768, preferably 106 to 768, more preferably 107 to 768, more preferably 109 to 768, more preferably 111 to 768, more preferably 112 to 768, more preferably 113 to 768, more preferably 116 to 768, more preferably 121 to 768, in particular 108 to 768, of SEQ ID No. 4; amino acid residues 101 to 768, preferably 106 to 768, more preferably 107 to 768, more preferably 109 to 768, more preferably 111 to 768, more preferably 112 to 768, more preferably 113 to 768, more preferably 116 to 768, more preferably 121 to 768, in particular 108 to 768, of SEQ ID No. 6; amino acid residues 101 to 783, preferably 106 to 783, more preferably 107 to 783, more preferably 109 to 783, more preferably 111 to 783, more preferably 112 to 783, more preferably 113 to 783, more preferably 116 to 783, more preferably 121 to 783, in particular 108 to 783, of SEQ ID No. 8; amino acid residues 101 to 773, preferably 106 to 773, more preferably 107 to 773, more preferably 109 to 773, more preferably 111 to 773, more preferably 112 to 773, more preferably 113 to 773, more preferably 116 to 773, more preferably 121 to 773, in particular 108 to 773, of SEQ ID No. 10; amino acid residues 102 to 759, preferably 107 to 759, more preferably 109 to 759, more preferably 110 to 759, more preferably 112 to 759, more preferably 113 to 759, more preferably 114 to 759, more preferably 117 to 759, more preferably 122 to 759, in particular 111 to 759, of SEQ ID No. 14; amino acid residues 102 to 762, preferably 107 to 762, more preferably 109 to 762, more preferably 110 to 762, more preferably 112 to 762, more preferably 113 to 762, more preferably 114 to 762, more preferably 117 to 762, more preferably 122 to 762, in particular 111 to 762, of SEQ ID No. 16; amino acid residues 102 to 759, preferably 107 to 759, more preferably 109 to 759, more preferably 110 to 759, more preferably 112 to 759, more preferably 113 to 759, more preferably 114 to 759, more preferably 117 to 759, more preferably 122 to 759, in particular 111 to 759, of SEQ ID No. 18; amino acid residues 94 to 751, preferably 99 to 751, more preferably 101 to 751, more preferably 102 to 751, more preferably 104 to 751, more preferably 105 to 751, more preferably 106 to 751, more preferably 109 to 751, more preferably 114 to 751, in particular 103 to 751, of SEQ ID No. 20; amino acid residues 94 to 751, preferably 99 to 751, more preferably 101 to 751, more preferably 102 to 751, more preferably 104 to 751, more preferably 105 to 751, more preferably 106 to 751, more preferably 109 to 751, more preferably 114 to 751, in particular 103 to 751, of SEQ ID No. 22. 
     The proteolytic activity of the serine proteases of the present invention can also be reduced by influencing the promoter region of their respective genes naturally occurring within the plant or plant cell. The promoter region is located at the 5′ end of the nucleic acid region coding for the respective serine proteases and comprises typically 500 to 2000 nucleotides. Deletion, substitution or insertion of nucleotides within this region influences the transcription rate and consequently the proteolytic activity of the serine proteases within the plant and plant cell. 
     According to a preferred embodiment of the present invention a promoter of a gene encoding said at least one serine protease of the wild-type plant or plant cell is mutated in the genetically modified plant or plant cell at at least one position of its nucleic acid sequence to reduce its expression rate. 
     A mutation within said promoter may be a deletion or substitution within 100, preferably within 200, more preferably within 300, more preferably within 500, more preferably within 700, more preferably within 1000, nucleotides located adjacent and upstream to the 5′ end of the coding region encoding said at least one serine protease of a plant or plant cell. Whether a mutation within said region results in a reduction or prevention of the expression rate of said at least one serine protease can be determined by methods known in the art and by comparing the expression rate of said at least one serine protease in a plant or plant cell modified within the aforementioned region with the expression rate of the same enzyme(s) in a wild-type plant or plant cell. In a preferred embodiment of the present invention up to 100, preferably up to 200, more preferably up to 300, more preferably up to 500, more preferably up to 700, more preferably up to 1000, nucleotides located adjacent and upstream to the 5′ end of the coding region encoding said at least one serine protease of the wild-type plant or plant cell are deleted. In another preferred embodiment of the present invention 10 to 100, preferably 10 to 200, more preferably 50 to 300, more preferably 50 to 500, more preferably 100 to 700, more preferably 200 to 1000, nucleotides located adjacent and upstream to the 5′ end of the coding region encoding said at least one serine protease of the wild-type plant or plant cell are deleted. 
     In a particularly preferred embodiment of the present invention at least 30%, preferably at least 40%, more preferably at least 50%, more preferably at least 60%, more preferably at least 70%, more preferably at least 80%, more preferably at least 90%, more preferably at least 95%, in particular 100%, of the coding region of the serine proteases of the present invention having at least 80%, preferably at least 85%, more preferably at least 90%, more preferably at least 95%, more preferably at least 96%, more preferably at least 98%, more preferably at least 99%, in particular 100%, sequence identity to a serine protease consisting of an amino acid sequence selected from the group consisting of SEQ ID No. 2, SEQ ID No. 4, SEQ ID No. 6, SEQ ID No. 8, SEQ ID No. 10, SEQ ID No. 14, SEQ ID No. 16, SEQ ID No. 18, SEQ ID No. 20 and SEQ ID No. 22, preferably SEQ ID No. 2 or SEQ ID No. 14, i.e. a nucleic acid sequence selected from the group consisting of SEQ ID No. 3, SEQ ID No. 5, SEQ ID No. 7, SEQ ID No. 9, SEQ ID No. 11, SEQ ID No. 15, SEQ ID No. 17, SEQ ID No. 19, SEQ ID No. 21 and SEQ ID No. 23, preferably SEQ ID No. 3 or SEQ ID No. 15, are deleted in the plant or plant cell of the present invention by methods known in the art. 
     According to a preferred embodiment of the present invention an inhibitor (e.g.  Arabidopsis thaliana  subtilisin propeptide-like inhibitor 1, At1g71950;  A. thaliana  subtilisin propeptide-like inhibitor 2, At2g39851; S106g065370; S111g018590; Hohl M et al., 2017, J. Biol. Chem. 292, 6389-6401) of said at least one serine protease is overexpressed in the genetically modified plant or plant cell to reduce the expression rate of the at least one serine protease or to inhibit the proteolytic activity of the at least one serine protease. 
     In a particularly preferred embodiment of the present invention the serine protease inhibitor is  Arabidopsis thaliana  subtilisin propeptide-like inhibitor 1 (GenBank: AEE35257.1),  A. thaliana  subtilisin propeptide-like inhibitor 2 (GenBank: AEC09739.1), S106g065370 (SEQ ID No. 33) or S111g018590 (SEQ ID No. 34). 
     
       
         
           
               
               
            
               
                 (SEQ ID No. 33) 
                   
               
               
                 MMKKDQILSSILLFFFLFTAFITTMADSQASSQPSNESKVHIVYTEQPKDQEPEEYH 
                   
               
               
                 IKTLTSVLGSEEAAKEALLYSYKHAASGFSAKLTAEQVSELSKLPGVLQVVPSQTVQ 
               
               
                 LHTGRV 
               
               
                   
               
               
                 (SEQ ID No. 34) 
                   
               
               
                 MQKIQIIFLVFLLLFVADCEEAKVYIVFTENPQPKEFHIKTLASVLGSEDAAREALI 
                   
               
               
                 YSYKHVISGFAARLTPEQVSELAKKPGVLEIVPSRTYHLDGPKLK 
               
            
           
         
       
     
     According to a preferred embodiment of the present invention the genetically modified plant or plant cell comprises at least one exogenous nucleic acid molecule encoding for at least one protein or polypeptide of interest. 
     The genetically modified plant or plant cell can be used to produce/express at least one protein or polypeptide of interest which is not naturally occurring in said plant or plant cell. In order to allow the recombinant expression of heterologous polypeptides and proteins the respective nucleic acid molecule encoding said polypeptides and proteins are introduced into the plant or plant cell of the present invention. 
     The terms “exogenous protein”, “exogenous polypeptide”, “heterologous protein” or “heterologous polypeptide”, as defined herein, all refer to a protein or polypeptide that is not expressed by the plant or plant cell in nature, i.e. is not naturally occurring in plants and plant cells. This is in contrast with a homologous protein which is a protein naturally expressed by a plant or plant cell. The heterologous expression of polypeptides and proteins within a host cell can be achieved by means and methods known in the art and described below for the polypeptide of the present invention. 
     The exogenous nucleic acid molecule of the present invention can be a vector, preferably a plant vector, or a nucleic acid molecule carrying elements allowing cloning and/or the recombinant expression of heterologous proteins or polypeptides within a plant or plant cell. 
     The vector of the present invention can be used to clone the nucleic acid molecule of the present invention, as a shuttle or as an expression vector in host cells. Expression vectors may include an expression cassette which comprises various specified nucleic acid elements which permit transcription of a particular nucleic acid in a host cell. Typically, expression cassettes comprise, among other sequences, a nucleic acid to be transcribed, a promoter and a terminator. 
     The vector of the present invention can be designed to be integrated into the genome of the host cell. Alternatively the vector is designed to not integrate into the genome of a host cell allowing transient expression of the nucleic acid molecule of the present invention. In the latter case the vector remains in a non-integrated state free within the cell. 
     A “vector” according to the present invention refers to a nucleic acid used to introduce the nucleic acid molecule of the present invention into a host cell. Expression vectors permit transcription of a nucleic acid inserted therein. 
     In order to enable a host cell to express a polypeptide of the present invention encoded by the nucleic acid molecule as defined above the vector of the present invention comprises a promoter operably linked to the nucleic acid molecule. 
     As used herein, “operably linked” refers to a functional linkage between a promoter and the nucleic acid molecule encoding the polypeptide of the present invention, wherein the promoter sequence initiates and mediates transcription of the DNA sequence corresponding to said nucleic acid molecule. 
     The term “promoter”, as used herein, refers to a region of a nucleic acid molecule upstream from the start of transcription and involved in recognition and binding of RNA polymerase and other proteins to initiate transcription. Promoters are able to control (initiate) transcription in a cell. Plant promoters are able of initiating transcription in plant cells whether or not its origin is a plant cell. Such promoters include promoters obtained from plants, plant viruses and bacteria which comprise genes expressed in plant cells such as Agrobacterium or Rhizobium. The promoter used in the vector of the present invention can be “inducible” or “repressible”, i.e. under environmental control. Such promoters can be controlled by changing the cultivation conditions (e.g. temperature) or by adding specific substances. Of course, the promoter used in the vectors of the present invention may be a “constitutive” promoter. Constitutive promoters are active under most environmental conditions and express continuously a protein or polypeptide of interest. 
     According to a preferred embodiment of the present invention the promoter is selected from the group consisting of promoters active in plants and plant cells, like the cauliflower mosaic virus 35S promoter, opine (octopine, nopaline, etc.) synthase promoters, actin promoter, ubiquitin promoter, etc. 
     In order to prevent transcriptional activation of downstream nucleic acid sequences by upstream promoters the vector of the present invention may comprise a “terminator” or “terminator sequence”. According to a preferred embodiment of the present invention the vector comprises a terminator which is preferably a g7T terminator. 
     According to a preferred embodiment of the present invention the exogenous/heterologous polypeptide or protein is of animal origin, preferably a mammalian, more preferably a human, polypeptide. 
     Polypeptides and proteins “of animal origin”, as used herein, refers to polypeptides which are not naturally occurring in plants and plant cells or any other non-animal organism. Polypeptides of animal origin can be derived from the genome of animals, preferably mammals, and are usually expressed in animals. 
     According to a further embodiment of the present invention the heterologous animal polypeptide is an antibody or a variant thereof. 
     Examples of heterologous polypeptides and proteins that can be advantageously produced by the plants or plant cells of the present invention include antibodies or variants thereof which are selected from the group consisting of monoclonal antibodies, chimeric antibodies, humanized antibodies, human antibodies, multispecific antibodies, Fab, Fab′, F(ab′) 2 , antigen-binding Fc fragments (Fcab) and derivatives thereof, Fv, domain antibodies (dAb), complementarity determining region (CDR) fragments, CDR-grafted antibodies, single-chain antibodies (ScFv), single chain antibody fragments, diabodies, triabodies, tetrabodies, minibodies, linear antibodies, chelating recombinant antibodies, tribodies, bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIP), camelized antibodies, VHH containing antibodies and polypeptides that comprise at least a portion of an immunoglobulin that is sufficient to confer specific antigen binding to the polypeptide, such as one, two, three, four, five or six CDR sequences. 
     According to a particularly preferred embodiment of the present invention the antibody is an antibody binding to a human immunodeficiency virus (HIV) surface protein. 
     As used herein, the term “specific for” can be used interchangeably with “binding to” or “binding specifically to”. These terms characterize molecules that bind to an antigen or a group of antigens with greater affinity (as determined by, e.g., ELISA or surface plasmon resonance spectroscopy assays) than other antigens or groups of antigens. According to the present invention molecules “specific for” an antigen may also be able to bind to more than one, preferably more than two, more preferably more than three, even more preferably more than five, antigens. Such molecules are defined to be “cross-reactive” (e.g. cross-reactive immunoglobulins, cross-reactive antigen binding sites). 
     The antibody expressed by the plant cell and plant of the present invention is preferably an antibody selected from the group consisting of 2F5 (Zwick et al., 2004, J. Virol. 78, 3155-3161), 2G12 (Doores et al., 2010, J. Virol. 84, 10690-10699), PG9 (Loos et al., 2015, Proc. Natl. Acad. Sci. USA 112, 12675-12680), PG16 (Pancera et al., 2013, Nat. Struct. Mol. Biol. 20, 804-813) and variants thereof. 
     It is known that non-cleaved antibodies may have a greater binding affinity to an antigen compared to their cleaved versions. This in effect is particularly significant for antibodies like 2F5, 2G12, PG9, PG16 and variants thereof. Therefore, it is particularly advantageous to provide efficient tools for producing non-cleaved 2F5, 2G12, PG9, PG16 and variants thereof. 
     According to a preferred embodiment of the present invention the antibody variant is selected from the group consisting of 2G12 comprising modifications at IH 19  (Doores et al., 2010, J. Virol. 84, 10690-10699). 
     According to a preferred embodiment of the present invention the antibody variant is selected from the group consisting of PG9 comprising modifications at NL 23  (Loos et al., 2015, Proc. Natl. Acad. Sci. USA 112, 12675-12680). 
     According to a preferred embodiment of the present invention the antibody variant is selected from the group consisting of PG9 comprising modifications at TL 94 , RL 95  and R L95A  (Pancera et al., 2013, Nat. Struct. Mol. Biol. 20, 804-813). 
     According to a preferred embodiment of the present invention the plant or plant cell is of the genus  Nicotiana  and preferably a species selected from the group consisting of  Nicotiana benthamiana  and  Nicotiana tabacum.    
     Further preferred plants to be used according to the present invention include  Nicotiana benthamiana , tobacco ( Nicotiana tabacum ),  Nicotiana  spp,  Arabidopsis thaliana , tomato ( Solanum lycopersicum ), potato ( Solanum tuberosum ), duckweed ( Lemna minor ), mosses (e.g.  Physcomitrella ), corn ( Zea mays ), rice ( Oryza sativa ), wheat ( Triticum aestivum ), peas ( Pisum sativum ), flaxseed ( Linum usitatissimum ) and rapeseed ( Brassica napus ), in particular the  Nicotiana benthamiana  line C105 (Strasser R et al. Plant Biotechnol J 6(2008):392-402). 
     A further aspect of the present invention relates to a serine protease consisting of an amino acid sequence selected from the group consisting of SEQ ID No. 2, SEQ ID No. 4, SEQ ID No. 6, SEQ ID No. 8, SEQ ID No. 10, SEQ ID No. 14, SEQ ID No. 16, SEQ ID No. 20 and SEQ ID No. 22, preferably SEQ ID No. 2 or SEQ ID No. 14. 
     Another aspect of the present invention relates to a nucleic acid molecule encoding a serine protease according to the present invention. 
     The nucleic acid molecule of the present invention encoding a serine protease as defined herein can be used to recombinantly express said serine protease. The specificity of the serine proteases of the present invention can be used in methods or organisms where such a cleavage specificity is desired. These methods may involve the use of non-plant organisms like animals or microorganisms. 
     The nucleic acid molecule of the present invention can be part of a vector which can be used for cloning or expression purposes. Respective vectors are well-known in the art. 
     The nucleic acid according to the present invention may encode a subtilisin-like serine protease and may comprise or consist of a nucleic acid sequence selected from the group consisting of SEQ ID No. 3, SEQ ID No. 5, SEQ ID No. 7, SEQ ID No. 9, SEQ ID No. 11, SEQ ID No. 15, SEQ ID No. 17, SEQ ID No. 21 and SEQ ID No. 23, preferably SEQ ID No. 3 or SEQ ID No. 15. 
     The nucleic acid molecule encoding a subtilisin-like serine protease comprising or consisting of a nucleic acid sequence selected from the group consisting of SEQ ID No. 3, SEQ ID No. 5, SEQ ID No. 7, SEQ ID No. 9, SEQ ID No. 11, SEQ ID No. 15, SEQ ID No. 17, SEQ ID No. 21 and SEQ ID No. 23, preferably SEQ ID No. 3 or SEQ ID No. 15, may comprise a nucleotide stretch encoding a tag sequence for detection and affinity purification, preferably at the N- or C-terminus, more preferably at the C-terminus of the polypeptide. This tag may consist of 3 to 60, preferably 3 to 45, more preferably 6 to 30, more preferably 3 to 18, in particular 18, nucleotides (n). In a particularly preferred embodiment of the present invention the tag consists of or comprises the nucleic acid stretch encoding the amino acid sequence HHHHHH. 
     Another aspect of the present invention relates to a polypeptide encoded by a nucleic acid molecule according to the present invention, preferably a polypeptide comprising or consisting of an amino acid sequence selected from the group consisting of SEQ ID No. 2, SEQ ID No. 4, SEQ ID No. 6, SEQ ID No. 8, SEQ ID No. 10, SEQ ID No. 14, SEQ ID No. 16, SEQ ID No. 20 and SEQ ID No. 22, most preferably SEQ ID No. 2 or SEQ ID No. 14. 
     The serine proteases of the present invention may comprise a tag sequence for detection and/or affinity purification, preferably at the N- or C-terminus, more preferably at the C-terminus. This tag may consist of 1 to 20, preferably 1 to 15, more preferably 2 to 10, more preferably 2 to 6, in particular 6 amino acid residues. In a particularly preferred embodiment of the present invention the tag consists of or comprises the amino acid sequence HHHHHH. 
     The terms “polypeptide” and “protein” refer to a polymer of amino acid residues, wherein a “polypeptide” polymer may comprise more than 5 amino acid residues and a “protein” polymer may comprise more than 100 amino acid residues. The term “polypeptide” may, thus, include also “proteins”. 
     Yet, another aspect of the present invention relates to a plant or plant cell capable of cleaving a polypeptide preferably of animal origin heterologously produced in said plant or plant cell comprising a nucleic acid molecule or a vector according to the present invention. 
     In order to support the correct folding of heterologous, preferably mammalian, more preferably human, proteins or polypeptides expressed in plants and plant cells said proteins or polypeptides may be fused to another polypeptide or peptide, i.e. a fusion partner (see e.g. Sainsbury et al., 2016, Front. Plant Sci. 7, 141). Said fusion partner is linked via a peptide to the protein or polypeptide to be heterologously expressed whereby said peptide comprises cleavage sites which are recognized and cut by the serine proteases of the present invention. The removal of the aforementioned fusion partner can be done directly in the plant and plant cell of the present invention which expresses said serine protease. 
     The proteins and polypeptides heterologously produced in said plant or plant cell may be fused to peptidic tags which can be used to facilitate the purification of the proteins. Said peptidic tags may have, for instance, a binding affinity to other chemical moieties which may be immobilized on a solid support. The peptidic tags are linked via a peptide comprising a cleavage site which is recognized and cut by the serine proteases of the present invention to the heterologously produced proteins and polypeptides. 
     The plant and plant cell of the present invention may carry the nucleic acid molecule of the present invention in a non-integrated form (e.g. as a vector) or may be a “transgenic plant” or “transgenic plant cell”. Such a plant or plant cell comprises within its genome a heterologous nucleic acid molecule. This heterologous nucleic acid molecule is usually stably integrated within the genome such that the polynucleotide is passed on to successive generations. In order to allow the plant and plant cell to express the polypeptide of the present invention, its encoding nucleic acid molecule is operably linked to a promoter. 
     The nucleic acid molecule and the vector according to the present invention enable a plant or plant cell to cleave polypeptides and proteins expressed in said plant or plant cell. Therefore, the transgenic plant or plant cell of the present invention comprise preferably a nucleic acid molecule encoding a heterologous polypeptide operably linked to a promoter region. 
     Another aspect of the present invention relates to a method for producing at least one protein or polypeptide of interest by cultivating a genetically modified plant or plant cell according to the present invention. 
     Yet, another aspect of the present invention relates to a method of recombinantly producing a non-cleaved polypeptide of animal origin comprising the step of cultivating a plant or plant cell according to the present invention. 
     Methods and means to cultivate recombinant plants and plant cells are known in the art (e.g. Plant Biotechnology and Genetics: Principles, Techniques, and Applications, edited by C. N. Stewart, 2008, Wiley, ISBN 978-0-470-04381-3). 
     EXAMPLES 
     Materials and Methods 
     1. Cloning of Neutralizing Anti-HIV Antibody 2G12 and Variant Thereof 
     The signal peptide of barley a-amylase (amino acid residues 1 to 24 of the amino acid sequence of acc. no. CAX 51374.1 ) was cloned into MagnIcon vectors pICH26033 and pICH31160 (Niemer M et al. Biotechnol J 9(2014):493-500) to give rise to pICHα26033 and pICHα31160. The sequences encoding the 2G12 heavy and light chains (omitting their authentic signal peptides) were amplified from the corresponding pDONR221 constructs (Loos A et al. Plant Biotechnol J 9(2011):179-192) by PCR. The fragments thus generated were then inserted into the BsaI sites of pICHα31160 (heavy chain) and pICHα26033 (light chain). The domain-swapping point mutation 119R (Doores KJ et al. J Virol 84(2010):10690-10699) was introduced into the 2G12 heavy-chain sequence by site-directed mutagenesis. The mutated product was then cloned into pICHα31160 as outlined above. 
     2G12HC (SEQ ID No. 24; PDB-database: 1ZLS, 1ZLU, 1ZLV, 1ZLW, 2OQJ, 3OAY, 3OAZ, 3OB0) cDNA was PCR-amplified from pDONR221/2G12HC (Loos A et al. Plant Biotechnol J 9(2011):179-192), without signal peptide but with 5′- and 3′ BsaI restriction sites. 
     2G12HC consists of amino acid sequence SEQ ID No. 24, whereby the signal peptide of barley α-amylase is marked in bold and italic: 
     
       
         
           
               
               
            
               
                    EVQLVESGGGLVKAGGSLILSCGVSNFRISAHTM 
                   
               
               
                 NWVRRVPGGGLEWVASISTSSTYRDYADAVKGRFTVSRDDLEDFVYLQMHKMRVEDTA 
               
               
                 IYYCARKGSDRLSDNDPFDAWGPGTVVTVSPASTKGPSVFPLAPSSKSTSGGTAALGC 
               
               
                 LVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNV 
               
               
                 NHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVT 
               
               
                 CVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKE 
               
               
                 YKCKVSNKAFPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSD 
               
               
                 IAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHN 
               
               
                 HYTQKSLSLSPGK 
               
            
           
         
       
     
     2G12HC is encoded by nucleotide sequence SEQ ID No. 25 (including a stop codon), whereby the nucleic acid stretch encoding the signal peptide of barley α-amylase is marked in bold and italic: 
     
       
         
           
               
               
            
               
                 
                   
                   
                   
                 
                   
               
               
                    gaggtgcagctggtggagtctgggggaggcctggtcaaggcggg 
               
               
                 aggatccctcatactctcctgtggagtctctaattttagaatctctgcccataccatg 
               
               
                 aattgggtccgccgggttccagggggggggctggagtgggtcgcttccattagtacga 
               
               
                 gttccacttatagagactatgcagacgctgtgaagggccgattcaccgtttccagaga 
               
               
                 cgacctcgaagactttgtgtatttgcaaatgcacaaaatgagagtcgaagacacggct 
               
               
                 atttattactgcgccagaaagggatctgacagactaagcgacaacgatccttttgatg 
               
               
                 cctgggggccaggaacagtggtcaccgtctctcccgcctccaccaagggcccatcggt 
               
               
                 cttccccctggcaccctcctccaagagcacctctgggggcacagcggccctgggctgc 
               
               
                 ctggtcaaggactacttccccgaaccggtgacggtgtcgtggaactcaggcgccctga 
               
               
                 ccagcggcgtgcacaccttcccggctgtcctacagtcctcaggactctactccctcag 
               
               
                 cagcgtggtgaccgtgccctccagcagcttgggcacccagacctacatctgcaacgtg 
               
               
                 aatcacaagcccagcaacaccaaggtggacaagaaagttgagcccaaatcttgtgaca 
               
               
                 aaactcacacatgcccaccgtgcccagcacctgaactcctggggggaccgtcagtctt 
               
               
                 cctcttccccccaaaacccaaggacaccctcatgatctcccggacccctgaggtcaca 
               
               
                 tgcgtggtggtggacgtgagccacgaagaccctgaggtcaagttcaactggtacgtgg 
               
               
                 acggcgtggaggtgcataatgccaagacaaagccgcgggaggagcagtacaacagcac 
               
               
                 gtaccgtgtggtcagcgtcctcaccgtcctgcaccaggactggctgaatggcaaggag 
               
               
                 tacaagtgcaaggtctccaacaaagccttcccagcccccatcgagaaaaccatctcca 
               
               
                 aagccaaagggcagccccgagaaccacaggtgtacaccctgcccccatcccgggatga 
               
               
                 gctgaccaagaaccaggtcagcctgacctgcctggtcaaaggcttctatcccagcgac 
               
               
                 atcgccgtggagtgggagagcaatgggcagccggagaacaactacaagaccacgcctc 
               
               
                 ccgtgctggactccgacggctccttcttcctctacagcaagctcaccgtggacaagag 
               
               
                 caggtggcagcaggggaacgtcttctcatgctccgtgatgcatgaggctctgcacaac 
               
               
                 cactacacgcagaagagcctctccctgtctccgggtaaatga 
               
            
           
         
       
     
     2G12HC cDNA encoding an I19R mutation (SEQ ID No. 26; PDB-database: 3OAU) was generated by site-directed mutagenesis, without signal peptide but with 5′- and 3′ BsaI restriction sites. 
     2G12HC (encoding an I19R mutation) consists of amino acid sequence SEQ ID No. 26, whereby the signal peptide of barley α-amylase is marked in bold and italic: 
     
       
         
           
               
               
            
               
                    EVQLVESGGGLVKAGGSLRLSCGVSNFRISAHTM 
                   
               
               
                 NWVRRVPGGGLEWVASISTSSTYRDYADAVKGRFTVSRDDLEDFVYLQMHKMRVEDTA 
               
               
                 IYYCARKGSDRLSDNDPFDAWGPGTVVTVSPASTKGPSVFPLAPSSKSTSGGTAALGC 
               
               
                 LVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNV 
               
               
                 NHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVT 
               
               
                 CVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKE 
               
               
                 YKCKVSNKAFPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSD 
               
               
                 IAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHN 
               
               
                 HYTQKSLSLSPGK 
               
            
           
         
       
     
     2G12HC (encoding an I19R mutation) is encoded by nucleotide sequence SEQ ID No. 27 (including a stop codon), whereby the nucleic acid stretch encoding the signal peptide of barley α-amylase is marked in bold and italic: 
     
       
         
           
               
               
            
               
                 
                   
                   
                   
                 
                   
               
               
                    gaggtgcagctggtggagtctgggggaggcctggtcaaggcggg 
               
               
                 aggatccctcagactctcctgtggagtctctaattttagaatctctgcccataccatg 
               
               
                 aattgggtccgccgggttccagggggggggctggagtgggtcgcttccattagtacga 
               
               
                 gttccacttatagagactatgcagacgctgtgaagggccgattcaccgtttccagaga 
               
               
                 cgacctcgaagactttgtgtatttgcaaatgcacaaaatgagagtcgaagacacggct 
               
               
                 atttattactgcgccagaaagggatctgacagactaagcgacaacgatccttttgatg 
               
               
                 cctgggggccaggaacagtggtcaccgtctctcccgcctccaccaagggcccatcggt 
               
               
                 cttccccctggcaccctcctccaagagcacctctgggggcacagcggccctgggctgc 
               
               
                 ctggtcaaggactacttccccgaaccggtgacggtgtcgtggaactcaggcgccctga 
               
               
                 ccagcggcgtgcacaccttcccggctgtcctacagtcctcaggactctactccctcag 
               
               
                 cagcgtggtgaccgtgccctccagcagcttgggcacccagacctacatctgcaacgtg 
               
               
                 aatcacaagcccagcaacaccaaggtggacaagaaagttgagcccaaatcttgtgaca 
               
               
                 aaactcacacatgcccaccgtgcccagcacctgaactcctggggggaccgtcagtctt 
               
               
                 cctcttccccccaaaacccaaggacaccctcatgatctcccggacccctgaggtcaca 
               
               
                 tgcgtggtggtggacgtgagccacgaagaccctgaggtcaagttcaactggtacgtgg 
               
               
                 acggcgtggaggtgcataatgccaagacaaagccgcgggaggagcagtacaacagcac 
               
               
                 gtaccgtgtggtcagcgtcctcaccgtcctgcaccaggactggctgaatggcaaggag 
               
               
                 tacaagtgcaaggtctccaacaaagccttcccagcccccatcgagaaaaccatctcca 
               
               
                 aagccaaagggcagccccgagaaccacaggtgtacaccctgcccccatcccgggatga 
               
               
                 gctgaccaagaaccaggtcagcctgacctgcctggtcaaaggcttctatcccagcgac 
               
               
                 atcgccgtggagtgggagagcaatgggcagccggagaacaactacaagaccacgcctc 
               
               
                 ccgtgctggactccgacggctccttcttcctctacagcaagctcaccgtggacaagag 
               
               
                 caggtggcagcaggggaacgtcttctcatgctccgtgatgcatgaggctctgcacaac 
               
               
                 cactacacgcagaagagcctctccctgtctccgggtaaatga 
               
            
           
         
       
     
     2G12LC (SEQ ID No. 28; PDB-database: 1ZLS, 1ZLU, 1ZLV, 1ZLW, 2OQJ, 3OAU, 3OAY, 3OAZ, 3OB0) cDNA was PCR-amplified from pDONR221/2G12LC (Loos A et al. Plant Biotechnol J 9(2011):179-192), without signal peptide but with 5′- and 3′ BsaI restriction sites. 
     2G12LC consists of amino acid sequence SEQ ID No. 28, whereby the signal peptide of barley α-amylase is marked in bold and italic: 
     
       
         
           
               
               
            
               
                    DVVMTQSPSTLSASVGDTITITCRASQSIETWLA 
                   
               
               
                 WYQQKPGKAPKLLIYKASTLKTGVPSRFSGSGSGTEFTLTISGLQFDDFATYHCQHYA 
               
               
                 GYSATFGQGTRVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKV 
               
               
                 DNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKS 
               
               
                 FNRGEC 
               
            
           
         
       
     
     2G12LC is encoded by nucleotide sequence SEQ ID No. 29 (including a stop codon), whereby the nucleic acid stretch encoding the signal peptide of barley α-amylase is marked in bold and italic: 
     
       
         
           
               
               
            
               
                 
                   
                   
                   
                 
                   
               
               
                    gatgttgtgatgactcagtctccttccaccctgtctgcatctgt 
               
               
                 cggagacacaatcaccatcacttgccgggccagtcagagtattgaaacctggttggcc 
               
               
                 tggtatcagcagaagccagggaaagccccaaaactcctaatctacaaggcgtctactt 
               
               
                 taaaaactggagtcccgtcaagattcagcggcagtggatctggaacagagttcactct 
               
               
                 taccatcagtggcctgcagttcgatgactttgcaacttatcactgtcagcactatgct 
               
               
                 ggttattcagcgacgttcggccaggggaccagggtggagatcaaacgaactgtggctg 
               
               
                 caccatctgtcttcatcttcccgccatctgatgagcagttgaaatctggaactgcctc 
               
               
                 tgttgtgtgcctgctgaataacttctatcccagagaggccaaagtacagtggaaggtg 
               
               
                 gataacgccctccaatcgggtaactcccaggagagtgtcacagagcaggacagcaagg 
               
               
                 acagcacctacagcctcagcagcaccctgacgctgagcaaagcagactacgagaaaca 
               
               
                 caaagtctacgcctgcgaagtcacccatcagggcctgagctcgcccgtcacaaagagc 
               
               
                 ttcaacaggggagagtgttag 
               
            
           
         
       
     
     2G12HC and 2G12HC (encoding an 119R mutation) were inserted into pICHα31160 in frame after the barley α-amylase signal peptide. 2G12LC was inserted into pICHα26033 in frame after the barley α-amylase signal peptide. 
     The vectors used for the expression of antibodies 2F5 and PG9 have been described (Niemer M et al. Biotechnol J 9(2014):493-500). 
     All vectors were transformed into  Escherichia coli  by electroporation and upon sequence confirmation into the  Agrobacterium tumefaciens  strains GV3101pMP90RK or UIA143. 
     2. Cloning of Subtilisin-Like Serine Protease Constructs 
     RNA was extracted from 35-mg samples of leaves from 4-week-old  Nicotiana benthamiana  C105 plants lacking plant-specific α1,3-fucosylation and β1,2-xylosylation (Strasser R et al. Plant Biotechnol J 6(2008):392-402) using the SV Total RNA Isolation Kit (Promega). First-strand cDNA was synthesized from 1 μg RNA using the RevertAid H Minus First Strand cDNA Synthesis Kit (Thermo Scientific) and oligo(dT) 18  as primer. For expression in  Nicotiana benthamiana  C105 plants, the coding sequences of the subtilisin-like serine proteases SBT1 and SBT2 (SEQ ID No. 3 and SEQ ID No. 15) were PCR-amplified using Q5 High-Fidelity DNA polymerase (New England Biolabs) and then inserted into a suitable expression vector, e.g. pPT2 (Strasser R et al. Biochem J 387(2005):385-391) or pART27 (Schardor K et al. Science 354 (2016): 1594-1597). After transformation into  E. coli  and sequence confirmation, all constructs were transformed into  Agrobacterium tumefaciens , e.g. strain UIA143pMP90. 
     3. In Planta Expression of Monoclonal Antibodies 
       Nicotiana benthamiana  C105 plants were grown for 4-5 weeks at 24° C. with a 16-h light: 8-h dark photoperiod. Infiltration with agrobacteria carrying the respective expression vectors was then performed as reported previously (Strasser R et al. Plant Biotechnol J 6(2008):392-402). Briefly, overnight cultures were pelleted and then resuspended in infiltration buffer (25 mM Mes buffer (pH 5.5), 25 mM MgSO 4 , 0.1 mM acetosyringone) at an OD 600  of 0.2 (1.0 OD 600  corresponds to 5×10 8  cells/mL). In the case of 2G12 and PG9 expression, equal amounts of the strains carrying the respective heavy and light chain constructs were used. Infiltrated N. benthamiana leaves were harvested after 4-5 days. 
     4. Monoclonal Antibody (mAb) Purification 
     Leaf material (see item 3) infiltrated with the transformed  Agrobacterium tumefaciens  strains described under item 1 was crushed under liquid nitrogen, extracted twice for 20 min on ice with 0.1 M Tris/HCl (pH 7.0) containing 0.5 M NaCl, 40 mM ascorbic acid and 1 mM EDTA (2 mL per gram leaf wet weight). After a centrifugation step (4° C., 30 min, 27500 g), the extract was clarified by a series of filtration steps with pore sizes ranging from 10 μm to 0.2 μm (Roth, AP27.1, Roth, AP51.1, Roth, CT92.1, Roth, KH54.1). Antibodies were then purified by affinity chromatography on a column packed with 1 mL rProtein A Sepharose 4 Fast Flow (GE Healthcare, 17-1279-01), using 0.1 M glycine/HCl (pH 3.0) for elution. Protein-containing eluate fractions were immediately neutralized by addition of 0.1 M Tris/HC1 (pH 8.0), dialyzed against phosphate-buffered saline (PBS) containing 0.02% (v/v) NaN 3  and then concentrated by ultrafiltration using Amicon YM30 centrifugal filter units. 
     In the case of PG9, an additional size exclusion chromatography step was included to remove antibody aggregates. After dialysis against SEC buffer (10 mM Tris/HCl, 50 mM NaCl, pH 7.5), the affinity-purified sample (1 mL) was loaded onto a Superdex 200 16/600 column (GE Healthcare) operated at a flow rate of 1 mL min −8 . Fractions corresponding to the elution position of monomeric PG9 were combined, dialyzed against PBS containing 0.02% (v/v) NaN3 and then concentrated by ultrafiltration as above. 
     5. Preparation of Apoplastic Fluid 
     For the recovery of apoplastic fluid, fully expanded leaves of  Nicotiana benthamiana  C105 plants (Strasser R et al. Plant Biotechnol J 6(2008):392-402) were submerged in 100 mM sodium acetate/40 mM ascorbic acid (pH 5.5) prior to vacuum exposure in a desiccator. Exogenous buffer was removed prior to centrifugation of the leaves for 15 min at 2000 g and 4° C. The recovered solution was then concentrated 10-20 fold using Microsep Advance centrifugal devices (10K MWCO; Pall Corporation). The total protein content of the concentrate was determined with the Bio-Rad Protein Assay kit (Bio-Rad), using bovine serum albumin (BSA) as a standard. 
     6. Identification of Subtilisin-Like Serine Proteases Present in Apoplastic Fluid 
     Concentrated apoplastic fluid prepared from  Nicotiana benthamiana  C105 plants (see item 5) was incubated for 1 h at 37° C. with 10 μM FP-biotin (Santa Cruz Biotechnology). The sample (2.5 mL) was then chromatographed on a PD-10 column (GE Healthcare) equilibrated in 100 mM sodium acetate (pH 5.5). The recovered eluate (3.5 ml) was incubated with 40 μL avidin-agarose beads (Sigma-Aldrich) for 16 h at 4° C. under constant agitation. The beads were washed four times with 4 mL 100 mM sodium acetate (pH 5.5) and once with 4 mL 10 mM Tris/HC1 (pH 6.8) prior to elution of the bound proteins with 80 μL SDS-PAGE sample buffer (5 min, 95° C.). The samples were then subjected to 12.5% SDS-PAGE under reducing conditions prior to staining of the gel with Coomassie Brilliant Blue R-250. The 60-80 kDa bands were excised, S-carboxamidomethylated and then digested with trypsin (Promega). The peptides thus generated were fractionated on a Thermo BioBasic C18 separation column (5 μm particle size, 150×0.36 mm) operated using a Dionex Ultimate 3000 system (Waters). A gradient from 95% solvent A and 5% solvent B (solvent A: 65 mM ammonium formate buffer at pH 3.0, B: 100% acetonitrile) to 32% B in 45 min was applied, followed by a 15-min gradient from 32% B to 75% B, at a flow rate of 6 μL/min. Eluted peptides were analysed online on a maXis 4G ETD Q-TOF mass spectrometer (Bruker) equipped with an electrospray ionization source and operated in the positive ion mode (m/z range: 150-2200). 
     7. Purification of Recombinant Subtilisin-Like Serine Proteases 
     Leaves of  Nicotiana benthamiana  C105 plants (Strasser R et al. Plant Biotechnol J 6(2008):392-402) expressing a subtilisin-like serine protease construct were submerged in extraction buffer (50 mM sodium phosphate/200 mM KCl, pH 7.0) prior to vacuum exposure in a desiccator. Exogenous buffer was removed prior to centrifugation of the leaves for 15 min at 2000 g and 4° C. The recovered solution was then supplemented with 20 mM imidazole and loaded on a 1 mL column of Chelating Sepharose (GE Healthcare) charged with Ni 2+  ions. After washing with the same buffer, the recombinant subtilisin-like serine protease was eluted with 250 mM imidazole in extraction buffer. Protein-containing eluate fractions were pooled, dialysed twice against 2 liters of extraction buffer and then concentrated by ultrafiltration using Microsep Advance centrifugal devices (10K MWCO; Pall Corporation). 
     8. In Vitro Degradation Assays 
     Monoclonal antibodies (200 μg/mL) produced in  Nicotiana benthamiana  C105 plants or CHO cells (2F5: Polymun Scientific, AB001; 2G12: Polymun Scientific, AB002; PG9, Polymun Scientific, AB015) were treated with concentrated apoplastic fluid of  Nicotiana benthamiana  C105 plants (100 μg/mL) or purified proteases (10-100 μg/mL) in 100 mM sodium acetate (pH 5.5). After incubation for up to 16 h, reactions were stopped by addition of SDS-PAGE sample buffer. 
     For isolation of mAb degradation products, antibodies (250 μg) were digested with apoplastic fluid or purified subtilisin-like serine proteases in 500 μL 100 mM sodium acetate (pH 5.5) to completion. After addition of 10 μL settled rProtein A Sepharose 4 Fast Flow beads, the samples were incubated for 2 h at 4° C. under constant agitation. The beads were then collected by centrifugation, washed four times with 500 μL PBS prior to elution of the bound antibody fragments with 100 μL 100 mM glycine (pH 3.0). The eluate was immediately neutralized with 10 μL 1 M Tris/HCl (pH 8.0). This elution/neutralization cycle was repeated four times. All eluate fractions were combined and concentrated by ultrafiltration after buffer exchange into PBS containing 0.02% (v/v) NaN 3 . 
     9. Western Blotting 
     Samples were fractionated by 12.5% SDS-PAGE under reducing conditions and then blotted on nitrocellulose membranes (GE Healthcare). After blocking for 1 h in PBS containing 3% BSA, the membranes were incubated with a γ-chain-specific goat anti-human IgG peroxidase conjugate (Sigma-Aldrich, A8775) at a concentration of 0.03 μg/mL PBS containing 0.05% Tween 20 (PBST) and 0.5% BSA for 90 min prior to development using chemiluminescence reagents (Bio-Rad). 
     10. Cleavage Site Analysis 
     N-terminal sequence analysis of bands blotted on polyvinylidene difluoride membranes (Bio-Rad) was performed by Edman degradation (Niemer M et al. Biotechnol J 9(2014):493-500). Alternatively, antibodies or their degradation products were digested with PNGase F (Roche) to release their N-glycans, reduced with 10 mM DTE (1 h, 56° C.) and then fractionated on a Thermo ProSwift RP-4H column (250×0.20 mm) using a Dionex UltiMate 3000 HPLC system (Thermo Scientific). After application of the sample (5 μl), elution was performed at 65° C. and a flow rate of 8 μl/min with a gradient of 20-95% solvent B (80% acetonitrile in 0.01% trifluoroacetic acid) in solvent A (0.05% trifluoroacetic acid) over 40 min as follows: 20-65% B (15 min), 65-95% B (5 min). Eluted polypeptides were analysed online on a maXis 4G ETD Q-TOF mass spectrometer (Bruker, Billerica, USA) equipped with an electrospray ionization source and operated in the positive ion mode (m/z range: 400-3800). The analysis files were deconvoluted (Maximum Entropy Method) using DataAnalysis 4.0 (Bruker) and manually annotated. 
     11. ELISA Assays 
     96-well enzyme-linked immunosorbent assay (ELISA) plates were coated with 100 ng per well of the respective antigen (2F5: gp41 peptide GGGLELDKWASL (Polymun Scientific); wild-type 2G12: HIV-1 UG37 gp140 (Polymun Scientific); PG9: HIV-1 ZM109 gp120, Loos A et al. Proc Natl Acad Sci USA 112(2015):12675-12680) or Fc-specific goat anti-human IgG F(ab′)2 fragments (Sigma-Aldrich, 13391) in 50 mM sodium carbonate/bicarbonate (pH 9.6) for 16 h at 4° C. The wells were then washed with PBST and subsequently incubated with mAb samples (starting concentration: 1-8 μg/mL) serially diluted (1:2) in PBST containing 1% BSA (dilution buffer) for 1 h at 22-24° C. After washing, bound antibodies were detected with 0.03 μg/mL γ-chain-specific goat anti-human IgG peroxidase conjugate (Sigma-Aldrich, A8775) in dilution buffer. After 1 h at 22-24° C., plates were washed and then developed with 0.1 mg/mL 3,3′,5,5′-tetramethylbenzidine (Sigma-Aldrich, T0440) and 0.006% H202 in 35 mM citric acid/65 mM sodium phosphate (pH 5.0) for 15 min at 22-24° C. Reactions were quenched by addition of 90 mM H 2 SO 4  prior to analysis by spectrophotometry at 450 nm. 
     A slightly modified ELISA procedure was used for the analysis of 2G12 containing an I19R mutation in the heavy chain (I19R 2G12). Wells were coated with 500 ng HIV-1 UG37 gp140 in PBS. Antibodies (20 μg/mL) were precomplexed with Fc-specific goat anti-human IgG F(ab′)2 fragments (10 μg/mL) for 15 min at 4° C. (Doores KJ et al. J Virol 84(2010):10690-10699) prior to appropriate dilution and addition to the wells. Detection of antigen-bound mAb molecules was performed with 0.1 μg/mL goat anti-human kappa chain peroxidase conjugate (Sigma-Aldrich, A7164). 
     12. Surface Plasmon Resonance Spectroscopy 
     The antigen binding kinetics of mAb 2F5 and its degradation products were determined by surface plasmon resonance spectroscopy using a Biacore T200 instrument (GE Healthcare) operated at 25° C. The running buffer was PBST containing 0.01% BSA. For multiple-cycle kinetics, purified antibody samples were diluted with running buffer to 37.5 μg/mL and then applied to a Protein A series S sensor chip (GE Healthcare) at a flow rate of 10 μL min −1 . After mAb capture (20 sec), the chip was exposed to increasing concentrations of gp41 peptide GGGLELDKWASL (for intact 2F5 mAb: 3, 9, 27, 81, 243 nM; for 2F5 degradation product: 50, 100, 200, 400, 800 nM) in running buffer (contact time: 30 sec; dissociation phase: 60 sec). Regeneration was performed with 10 mM glycine/HCl (pH 1.5) for 30 sec at a flow rate of 30 μL min −1 . A reference cell was operated in parallel (running buffer instead of mAb) to correct for unspecific binding of the analyte to the sensor chip surface. The sensorgrams thus obtained were analyzed with Biacore T200 Evaluation software by global fitting of the data to a 1:1 binding model. 
     13. Kinetic Analysis of Protease-Inhibitor Interactions 
     These assays were performed as described (Hohl M et al., 2017, J. Biol. Chem. 292, 6389-6401). A fluorigenic peptide substrate, Abz-VILDAVRA-Tyr(NO 2 ), was used for measuring the enzymatic activity of the subtilisin-like serine proteases tested. Recombinant inhibitors (prepared as described in Hohl M et al., 2017, J. Biol. Chem. 292, 6389-6401) were added in serial dilutions. Substrate cleavage was monitored in an Infinite M200 Pro microplate reader as increase in relative fluorescence (θ ex =320 nm; θ em =420 nm). Inhibition constants (K i ) were calculated using the Morrison equation. 
     Example 1 
     Apoplastic Fluid Proteases Generate Characteristic Fragments of the Monoclonal Antibodies 2F5, 2G12 and PG9 
     It was previously shown that the monoclonal anti-HIV antibody 2F5 can be cleaved within its CDR H3 loop when incubated with apoplastic proteases in vitro (Niemer M et al. Biotechnol J 9(2014):493-500). This has now been also observed for PG9 and a 2G12 variant (I19R 2G12) with a canonical domain architecture ( FIG. 1 ). To identify the cleavage sites, the degradation products were affinity-purified and then subjected to N-terminal sequencing analysis. In each case, the main cleavage site was located in the CDR H3 loop. For 2G12, additional cleavage sites were identified in the segment adjacent to the C-terminus of the CDR H3 loop (Table 1). 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Sequences of 2F5, 2G12 and PG9 heavy chains. CDR 
               
               
                 H3 loops (underlined) and their tips (italic) are 
               
               
                 highlighted. Cleavage sites by apoplastic fluid proteases 
               
               
                 are indicated by arrows. 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 2F5 (heavy chain) (SEQ ID No. 30): 
               
               
                 RITLKESGPPLVKPTQTLTLTCSFSGFSLSDFGVGVGWIRQPPGKALEWLAIIYSDDD 
               
               
                 KRYSPSLNTRLTITKDTSKNQVVLVMTRVSPVDTATYFCAH RRGPTT   LF  ↓  GV   PIARG   
               
               
                   PVNAMDV WGQGITVTISSTSTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVS 
               
               
                 WNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKV 
               
               
                 EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEV 
               
               
                 KFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKAFPAP 
               
               
                 IEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPEN 
               
               
                 NYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 I19R 2G12 (heavy chain) (SEQ ID No. 31): 
               
               
                 EVQLVESGGGLVKAGGSLRLSCGVSNFRISAHTMNWVRRVPGGGLEWVASISTSSTYR 
               
               
                 DYADAVKGRFTVSRDDLEDFVYLQMHKMRVEDTAIYYCAR KGSD  ↓  RLSD   NDPFDA WG 
               
               
                 PG ↓ TV ↓ VTVSPASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGAL 
               
               
                 TSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCD 
               
               
                 KTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYV 
               
               
                 DGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKAFPAPIEKTIS 
               
               
                 KAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTP 
               
               
                 PVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 PG9 (heavy chain) (SEQ ID No. 32): 
               
               
                 QRLVESGGGVVQPGSSLRLSCAASGFDFSRQGMHWVRQAPGQGLEWVAFIKYDGSEKY 
               
               
                 HADSVWGRLSISRDNSKDTLYLQMNSLRVEDTATYFCVR EAGGPDYR NGYNYY ↓ D ↓ F 
               
               
                 Y DGYYNYHYM  ↓  DV WGKGTTVIVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFP 
               
               
                 EPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT 
               
               
                 KVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS 
               
               
                 HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSN 
               
               
                 KALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWES 
               
               
                 NGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSL 
               
               
                 SLSPGK 
               
            
           
         
       
     
     Example 2 
     Proteolytic Cleavage Impairs Antigen Binding by 2F5, 2G12 and PG9 
     Previous studies have indicated that the CDR H3 loops are important for the interactions of 2F5, 2G12 and PG9 with their cognate antigens (Zwick M B et al. J Virol 78(2004):3155-3161; Doores K J et al. J Virol 84(2010):10690-10699; McLellan J S et al. Nature 480(2011):336-343). To investigate the antigen-binding properties of cleaved 2F5, 2G12 and PG9, suitable ligands and assay conditions had to be chosen. The antigen-binding activity of 2F5 can be tested with gp41-based peptides (Zwick M B et al. J Virol 78(2004):3155-3161). The nondomain-swapped variant of 2G12 (I19R 2G12) requires precomplexing with anti-Fc antibodies for detectable binding to HIV-1 envelope glycoproteins (Doores K J et al. J Virol 84(2010):10690-10699). PG9 has been described to bind to gp120 monomers of selected HIV strains including ZM109. Therefore HIV-1 ZM109 gp120 containing a C-terminal hexahistidine tag was expressed in mammalian cells and purified by metal-chelate affinity chromatography (Loos A et al. Proc Natl Acad Sci USA 112(2015):12675-12680). For all three antibodies, limited proteolysis within the CDR H3 loop by apoplastic proteases severely reduced binding to the respective antigen ( FIG. 2 a - c   ). For intact and cleaved 2F5, the avidity of the antigen-antibody interaction was also determined by surface plasmon resonance spectroscopy. These experiments demonstrated that cleavage of 2F5 by apoplastic proteases leads to a more than 20-fold reduction of its affinity to gp41 ( FIG. 3 ). 
     Example 3 
     SBT1 and SBT2 Cleave 2F5, 2G12 and PG9 at the Same Sites as Apoplastic Fluid 
     Previous studies have indicated that serine proteases participate in the proteolysis of 2F5 in  N. benthamiana  (Niemer M et al. Biotechnol J 9(2014):493-500). We have therefore utilized a biotin-tagged version of an activity-based probe for serine hydrolases for the selective labelling of serine proteases present in apoplastic fluid extracted from  N. benthamiana  leaves. After isolation with immobilized avidin, the captured proteins were identified by mass spectrometry. Exploiting the availability of a draft genome sequence for  N. benthamiana  (Bombarely A et al. Mol Plant Microbe Interact 25 (2012):1523-1530), the respective cDNAs could be cloned by RT-PCR using primers based on the peptide sequences obtained by mass spectrometry and then ectopically expressed in  N. benthamiana  by means of agroinfiltration. Two recombinant serine proteases, SBT1 and SBT2, were purified by nickel-chelate affinity chromatography exploiting hexahistidine tags exogenously added to their C-termini and then analysed for their capacity to degrade 2F5, PG9 and the non-domain exchanged variant of 2G12 (I19R 2G12). SBT1 was found to degrade all three antibodies. SBT2 was capable of acting on PG9 and I19R 2G12 ( FIG. 4 a   ). Two other serine proteases, trypsin and SBT3 (Cedzich A et al. J. Biol. Chem. 284 (2009):14068-14078), did not display cleavage activity ( FIG. 4 b   ) when tested on the monoclonal antibody 2F5. The cleavage products obtained upon digestion of 2F5, 119R 2G12 and PG9 with SBT1 and SBT2were then characterized by N-terminal sequencing and mass spectrometry. These studies revealed that the combined action of SBT1 and SBT2 can account for all cleavage sites generated by incubation of the antibodies with unfractionated apoplastic fluid (Tables 2 and 3). 
     
       
         
           
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Sequences of 2F5, 2G12 and PG9 heavy chains. CDR 
               
               
                 H3 loops (underlined) and their tips (italic) are 
               
               
                 highlighted. Cleavage sites by SBT1 are indicated by 
               
               
                 arrows. 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 2F5 (heavy chain) (SEQ ID No. 30): 
               
               
                 RITLKESGPPLVKPTQTLTLTCSFSGFSLSDFGVGVGWIRQPPGKALEWLAIIYSDDD 
               
               
                 KRYSPSLNTRLTITKDTSKNQVVLVMTRVSPVDTATYFCAH RRGPTT   LF  ↓  GV   PIARG   
               
               
                   PVNAMDV WGQGITVTISSTSTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVS 
               
               
                 WNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKV 
               
               
                 EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEV 
               
               
                 KFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKAFPAP 
               
               
                 IEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPEN 
               
               
                 NYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 I19R 2G12 (heavy chain) (SEQ ID No. 31): 
               
               
                 EVQLVESGGGLVKAGGSLRLSCGVSNFRISAHTMNWVRRVPGGGLEWVASISTSSTYR 
               
               
                 DYADAVKGRFTVSRDDLEDFVYLQMHKMRVEDTAIYYCAR KGSD   RLSD   NDPFDA WGPG 
               
               
                 ↓ TV ↓ VTVSPASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTS 
               
               
                 GVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKT 
               
               
                 HTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDG 
               
               
                 VEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKAFPAPIEKTISKA 
               
               
                 KGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPV 
               
               
                 LDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 PG9 (heavy chain) (SEQ ID No. 32): 
               
               
                 QRLVESGGGVVQPGSSLRLSCAASGFDFSRQGMHWVRQAPGQGLEWVAFIKYDGSEKY 
               
               
                 HADSVWGRLSISRDNSKDTLYLQMNSLRVEDTATYFCVR EAGGPDYR   NGYNYY  ↓  DFY   
               
               
                   DGYYNYHYM ↓ DV WGKGTTVIVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPE 
               
               
                 PVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTK 
               
               
                 VDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSH 
               
               
                 EDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNK 
               
               
                 ALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESN 
               
               
                 GQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLS 
               
               
                 LSPGK 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Sequences of 2F5, 2G12 and PG9 heavy chains. CDR 
               
               
                 H3 loops (underlined) and their tips (italic) are 
               
               
                 highlighted. Cleavage sites by SBT2 are indicated by 
               
               
                 arrows. 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
            
               
                 2F5 (heavy chain) (SEQ ID No. 30): 
               
               
                 RITLKESGPPLVKPTQTLTLTCSFSGFSLSDFGVGVGWIRQPPGKALEWLAIIYSDDD 
               
               
                 KRYSPSLNTRLTITKDTSKNQVVLVMTRVSPVDTATYFCAH RRGPTT   LFGV   PIARGPV   
               
               
                   NAMDV WGQGITVTISSTSTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWN 
               
               
                 SGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEP 
               
               
                 KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVICVVVDVSHEDPEVKF 
               
               
                 NWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKAFPAPIE 
               
               
                 KTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNY 
               
               
                 KTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 I19R 2G12 (heavy chain) (SEQ ID No. 31): 
               
               
                 EVQLVESGGGLVKAGGSLRLSCGVSNFRISAHTMNWVRRVPGGGLEWVASISTSSTYR 
               
               
                 DYADAVKGRFTVSRDDLEDFVYLQMHKMRVEDTAIYYCAR KGSD  ↓  RLSD   NDPFDA WG 
               
               
                 PGTVVTVSPASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSG 
               
               
                 VHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTH 
               
               
                 TCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGV 
               
               
                 EVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKAFPAPIEKTISKAK 
               
               
                 GQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVL 
               
               
                 DSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 
               
               
                   
               
               
                 PG9 (heavy chain) (SEQ ID No. 32): 
               
               
                 QRLVESGGGVVQPGSSLRLSCAASGFDFSRQGMHWVRQAPGQGLEWVAFIKYDGSEKY 
               
               
                 HADSVWGRLSISRDNSKDTLYLQMNSLRVEDTATYFCVR EAGGPDYR   NGYNYKD  ↓  F   Y   
               
               
                   DGYYNYHYMDV WGKGTTVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEP 
               
               
                 VTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKV 
               
               
                 DKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHE 
               
               
                 DPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKA 
               
               
                 LPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNG 
               
               
                 QPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSL 
               
               
                 SPGK 
               
            
           
         
       
     
     Example 4 
     SBT1 and SBT2 Can Be Effectively Inhibited By Plant Inhibitors of Subtilisin-Like Serine Proteases 
     In a recent study (Hohl M et al., 2017, J. Biol. Chem. 292, 6389-6401),  A. thaliana  subtilisin propeptide-like inhibitor 1(SPI-1) and three close relatives from  A. thaliana  (SPI-2) and  S. lycopersicum  (S106g065370, S111g018590) were described. Recombinant versions of these four inhibitors were now produced in  E. coli  following published procedures (Hohl M et al., 2017, J. Biol. Chem. 292, 6389-6401) and then tested for their potential to inhibit SBT1 (SEQ ID No. 2) and SBT2 (SEQ ID No. 14). All four inhibitors (At1,  A. thaliana  SPI-1; At2,  A. thaliana  SPI-2; S11, S106g065370; S12, S111g018590) were found to bind to SBT1 and SBT2 with high affinities, resulting in effective inhibition of the proteases ( FIG. 5 a - h   ). 
     Conclusion 
     The examples provided herein aimed at the identification of the proteases affecting the integrity and antigen-binding capacity of the three HIV-specific mAbs 2F5, 2G12 and PG9. Utilizing the activity-based probe FP-biotin, two subtilisin-like serine proteases could be isolated from apoplastic fluid of  Nicotiana benthamiana  C105 plants and identified by mass spectrometric analysis of their tryptic peptides. The coding sequences of these two proteases were cloned and then used for the expression of recombinant versions of the enzymes, which could be purified by affinity chromatography exploiting their C-terminal tags. Incubation of the mAbs 2F5, 2G12 and PG9 with the purified proteases led to cleavage of the antibodies at exactly the same positions as observed when treated with apoplastic fluid. These results indicate that the identified two subtilisin-like serine proteases are responsible for the fragmentation and inactivation of the mAbs 2F5, 2G12 and PG9 when expressed in plants. The two identified proteases are effectively inhibited by subtilisin propeptide-like inhibitors, which can be exploited for their targeted inactivation in plants.