Cathepsin Z, a Novel Human Cysteine Proteinase with a Short Propeptide Domain and a Unique Chromosomal Location (1998)

We have identified and characterized a novel human cysteine proteinase of the papain family. A full-length cDNA for this enzyme was cloned from a human brain cDNA library. Nucleotide sequence analysis revealed that the isolated cDNA codes for a polypeptide of 303 amino acids, tentatively called cathepsin Z, that exhibits structural features characteristic of cysteine proteinases. Fluorescent in situ hybridization experiments revealed that the human cathepsin Z gene maps to chromosome 20q13, a location that differs from all cysteine proteinase genes mapped to date. The cDNA encoding cathepsin Z was expressed inEscherichia coli as a fusion protein with glutathioneS-transferase, and after purification, the recombinant protein was able to degrade the synthetic peptide benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin, used as a substrate for cysteine proteinases. Northern blot analysis demonstrated that cathepsin Z is widely expressed in human tissues, suggesting that this enzyme could be involved in the normal intracellular protein degradation taking place in all cell types. Cathepsin Z is also ubiquitously distributed in cancer cell lines and in primary tumors from different sources, suggesting that this enzyme may participate in tumor progression as reported for other cathepsins. Finally, on the basis of a series of distinctive structural features, including diverse peptide insertions and an unusual short propeptide, together with its unique chromosomal location among cysteine proteinases, we propose that cathepsin Z may be the first representative of a novel subfamily of this class of proteolytic enzymes. We have identified and characterized a novel human cysteine proteinase of the papain family. A full-length cDNA for this enzyme was cloned from a human brain cDNA library. Nucleotide sequence analysis revealed that the isolated cDNA codes for a polypeptide of 303 amino acids, tentatively called cathepsin Z, that exhibits structural features characteristic of cysteine proteinases. Fluorescent in situ hybridization experiments revealed that the human cathepsin Z gene maps to chromosome 20q13, a location that differs from all cysteine proteinase genes mapped to date. The cDNA encoding cathepsin Z was expressed inEscherichia coli as a fusion protein with glutathioneS-transferase, and after purification, the recombinant protein was able to degrade the synthetic peptide benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin, used as a substrate for cysteine proteinases. Northern blot analysis demonstrated that cathepsin Z is widely expressed in human tissues, suggesting that this enzyme could be involved in the normal intracellular protein degradation taking place in all cell types. Cathepsin Z is also ubiquitously distributed in cancer cell lines and in primary tumors from different sources, suggesting that this enzyme may participate in tumor progression as reported for other cathepsins. Finally, on the basis of a series of distinctive structural features, including diverse peptide insertions and an unusual short propeptide, together with its unique chromosomal location among cysteine proteinases, we propose that cathepsin Z may be the first representative of a novel subfamily of this class of proteolytic enzymes. The cysteine proteinases belonging to the papain family represent a major component of the lysosomal proteolytic system and play an essential role in protein degradation and turnover (1Bond J.S. Butler P.E. Annu. Rev. Biochem. 1987; 56: 333-364Crossref PubMed Scopus (455) Google Scholar, 2Chapman H.A. Riese R.J. Shi G.P. Annu. Rev. Physiol. 1997; 59: 63-88Crossref PubMed Scopus (687) Google Scholar). In addition, these proteolytic enzymes appear to play an extracellular role in a number of normal and pathological conditions including bone remodeling (3Tezuka K. Tezuka Y. Maejima A. Sato T. Nemoto K. Kamioka H. Hakeda Y. Kumegawa M. J. Biol. Chem. 1994; 269: 1106-1109Abstract Full Text PDF PubMed Google Scholar), prohormone activation (4Krieger T.J. Hook V.Y.H. J. Biol. Chem. 1991; 266: 8376-8383Abstract Full Text PDF PubMed Google Scholar), rheumatoid arthritis (5Mort J.S. Recklies A.D. Poole A.R. Arthritis Rheum. 1984; 27: 509-515Crossref PubMed Scopus (123) Google Scholar), Alzheimer's disease (6Golde T.E. Estus S. Younkin L.H. Selkoe D.J. Younkin S.G. Science. 1992; 255: 728-730Crossref PubMed Scopus (623) Google Scholar), pulmonary emphysema (7Mason R.W. Johnson D.A. Barrett A.J. Chapman H.A. Biochem. J. 1986; 233: 925-927Crossref PubMed Scopus (148) Google Scholar), and cancer invasion and metastasis (8Sloane B.F. Semin. Cancer Biol. 1990; 1: 137-152PubMed Google Scholar). To date, nine human cysteine proteinases of the papain family have been isolated and characterized at the amino acid sequence level: cathepsin B (9Chan S.J. San Segundo B. McCormick M.B. Steiner D.F. Proc. Natl. Acad. Sci. U. S. A. 1986; 83: 7721-7725Crossref PubMed Scopus (229) Google Scholar), cathepsin L (10Gal S. Gottesman M.M. Biochem. J. 1988; 253: 303-306Crossref PubMed Scopus (100) Google Scholar, 11Joseph L.J. Chang L.C. Stamenkovich D. Sukhatme V.P. J. Clin. Invest. 1988; 81: 1621-1629Crossref PubMed Scopus (115) Google Scholar), cathepsin H (12Fuchs R. Machleidt W. Gassen H.G. Biol. Chem. Hoppe-Seyler. 1988; 369: 469-475Crossref PubMed Scopus (36) Google Scholar, 13Ritonja A. Popovic T. Kotnik M. Machleidt W. Turk V. FEBS Lett. 1988; 228: 341-345Crossref PubMed Scopus (75) Google Scholar), cathepsin S (14Wiederanders B. Brömme D. Kirschke H. von Figura K. Schmidt B. Peters C. J. Biol. Chem. 1992; 267: 13708-13713Abstract Full Text PDF PubMed Google Scholar, 15Shi G.P. Munger J.S. Meara J.P. Rich D.H. Chapman H.A. J. Biol. Chem. 1992; 267: 7258-7262Abstract Full Text PDF PubMed Google Scholar), cathepsin C (16Paris A. Strukelj B. Pungercar J. Renko M. Dolenc I. Turk V. FEBS Lett. 1995; 369: 326-330Crossref PubMed Scopus (79) Google Scholar), cathepsin O (17Velasco G. Ferrando A.A. Puente X.A. Sánchez L.M. López-Otı́n C. J. Biol. Chem. 1994; 269: 27136-27142Abstract Full Text PDF PubMed Google Scholar), cathepsin K (18Inaoka T. Bilbe G. Ishibashi O. Tezuka K. Kumegawa M. Kokubo T. Biochem. Biophys. Res. Commun. 1995; 206: 89-96Crossref PubMed Scopus (321) Google Scholar, 19Bromme D. Okamoto K. Wang B.B. Biroc S. J. Biol. Chem. 1996; 271: 2126-2132Abstract Full Text Full Text PDF PubMed Scopus (380) Google Scholar), cathepsin W (20Linnevers C. Smeekens S.P. Bromme D. FEBS Lett. 1997; 405: 253-259Crossref PubMed Scopus (98) Google Scholar), and cathepsin L2 (21Santamarı́a I Velasco G. Cazorla M. Fueyo A. Campo E. López-Otı́n C. Cancer Res. 1998; 58: 1624-1630PubMed Google Scholar). All of them contain an essential cysteine residue in their active site but differ in tissue distribution and in some enzymatic properties, including substrate specificities and pH stability. Furthermore, several groups have reported the existence of additional cysteine proteinases including cathepsins M, N, P, and T, which were originally identified because of their degrading activity on specific substrates such as aldolase, collagen, proinsulin, or tyrosine aminotransferase, but whose characterization at the molecular level has not yet been reported (22Pontremoli S. Melloni E. Salamino F. Sparatore B. Michetti M. Horecker B.L. Arch. Biochem. Biophys. 1982; 214: 376-385Crossref PubMed Scopus (24) Google Scholar, 23Maciewicz R. Etherington D. Biochem. J. 1988; 256: 433-440Crossref PubMed Scopus (137) Google Scholar, 24Docherty K. Carroll R.J. Steiner D.F. Proc. Natl. Acad. Sci. U. S. A. 1982; 79: 4613-4617Crossref PubMed Scopus (87) Google Scholar, 25Gohda E. Pitot H.C. J. Biol. Chem. 1981; 256: 2567-2572Abstract Full Text PDF PubMed Google Scholar). According to structural and functional data, it is well established that the different cysteine proteinases of the papain family are synthesized as preproenzymes, which are processed to the corresponding proenzymes and targeted to the lysosomes by the mannose 6-phosphate signal attached to them. The enzymes are further processed to mature forms consisting of either a single polypeptide chain or a two-chain form composed of heavy and light chains linked by a disulfide bond (26Berti P.J. Storer A.C. J. Mol. Biol. 1995; 246: 273-283Crossref PubMed Scopus (356) Google Scholar). However, in some cases, the precursors of these lysosomal enzymes escape from this processing pathway and continue along the secretory route, entering storage granules and being finally released into the extracellular space (27Kornfeld S. Mellman I. Annu. Rev. Cell Biol. 1989; 5: 483-525Crossref PubMed Scopus (1235) Google Scholar). In fact, a series of reports have shown that several lysosomal cysteine proteinases are released by tumor cells from different sources, supporting the concept that secreted lysosomal enzymes may play important roles in the developmnent of malignant processes (28Sloane B.F. Dunn J.R. Honn K.V. Science. 1981; 212: 1151-1153Crossref PubMed Scopus (323) Google Scholar, 29Recklies A.D. Poole A.R. Mort J.S. Biochem. J. 1982; 207: 633-636Crossref PubMed Scopus (42) Google Scholar, S. Gottesman M.M. J. Biol. Chem. 1986; Full Text PDF PubMed Google Scholar). Furthermore, lysosomal cysteine proteinases have been to be secreted by by or by from with the of and pathological conditions in which these enzymes may be involved H.A. Riese R.J. Shi G.P. Annu. Rev. Physiol. 1997; 59: 63-88Crossref PubMed Scopus (687) Google Scholar, S. Mellman I. Annu. Rev. Cell Biol. 1989; 5: 483-525Crossref PubMed Scopus (1235) Google Scholar). on the that a number of different cysteine proteinases could be for the of to this protein we have been in the that additional yet family could be by human for human cysteine proteinases to cathepsin originally cloned from a but widely distributed in human (17Velasco G. Ferrando A.A. Puente X.A. Sánchez L.M. López-Otı́n C. J. Biol. Chem. 1994; 269: 27136-27142Abstract Full Text PDF PubMed Google Scholar). We have also the and characterization of human a cysteine proteinase to other of the papain family and involved in A.A. Velasco G. Campo E. López-Otı́n C. Cancer Res. 1996; 56: Google Scholar, A.A. E. Velasco G. R. López-Otı́n C. J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). Finally, we have reported the of cathepsin a cysteine proteinase to cathepsin but a unique tissue distribution (21Santamarı́a I Velasco G. Cazorla M. Fueyo A. Campo E. López-Otı́n C. Cancer Res. 1998; 58: 1624-1630PubMed Google Scholar). In this we the chromosomal and structural and enzymatic characterization of a novel of this family of which has been tentatively called cathepsin and other used for molecular were from brain and cDNA in and Northern from different human and cancer cell lines were from were with from a from were synthesized by the in an and used after and were from and proteinase used expressed sequence chain was from A of the for with to human cysteine proteinases to a sequence from an tumor cDNA by T. K. M. M. M. T. M. G. M. J. T. F. E. R. A. and R. and a with for other cathepsins. for additional human expressed sequence to this we and to a specific for the gene encoding this novel cysteine was by of cDNA from a human brain cDNA as from this brain cDNA was for the of the cysteine proteinase specific and from the The was in a system from for of and The was with and cloned into The cloned cDNA was and to be with the cDNA was from the and used to a human brain cDNA to T. J. A Scholar). to the was for in pH and at The were for at in and to at with purification, several cloned were by and the into the site of were in the of and by the F. S. A.R. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar), either or cDNA specific and the S. were by for in the All were identified in analysis of and protein was with the of the of J. O. Res. 1984; PubMed Scopus Google Scholar). A human chromosome by the was by hybridization with the full-length cathepsin Z cDNA as were identified the cathepsin Z gene as demonstrated by and blot from of these was with the and used for in situ hybridization To of the was with and to normal from as A. J.P. Fueyo A. López-Otı́n C. Cell 1994; PubMed Scopus (24) Google Scholar). was were and were in a with a To an for of recombinant cathepsin Z in E. we first a the sequence for the mature human cathepsin Z by of the isolated full-length cDNA with and The was for of and the to The was with with and to the and The called was into E. coli and the cells were in at for with the and to an A of was to a of and the was for were by and in of by a and at for at The was with and with in pH The enzymatic activity of cathepsin Z in E. coli was or as substrates and the by Barrett and Kirschke A.J. Kirschke H. 1981; PubMed Scopus Google with were at in pH and was in a at and of and the was with at for and the activity was the substrate as Northern of of different human tissue and cancer cell lines or of from diverse tumor were at for in pH and were with the corresponding to the of the cathepsin Z were with for at and to and were by hybridization with an In an to novel of the papain family of cysteine proteinases, we a of the human for with to family analysis to the of a series of after a protein sequence with a of to the of the different cysteine proteinases of the papain family characterized to date. A cDNA of the sequence corresponding to these was by of from a human brain cDNA library. The was and its was by sequence The cloned was and used as a to the human brain cDNA for the of a of hybridization with the were was isolated from of these and their sequence was by of the revealed that all of them to from the which a novel human However, of these isolated cDNA in their sequence the corresponding to the of this novel human To this we a human cDNA as a a by and corresponding to the in the isolated brain cDNA of was isolated from a single hybridization with the and its sequence was analysis of this to by the for the brain cDNA as well as to the of the sequence from these analysis of the sequence revealed an with an at and with a at that at this first the identified codes for a protein of 303 amino and a molecular of for sequence the identified amino acid sequence and for the different human cysteine proteinases of the papain family characterized to that the of from with cathepsin C to with cathepsin B. this sequence the amino acid sequence from the human cDNA isolated in this all the structural features characteristic of the different of the papain family the of a sequence in the of the signal peptide which these enzymes to the secretory pathway (1Bond J.S. Butler P.E. Annu. Rev. Biochem. 1987; 56: 333-364Crossref PubMed Scopus (455) Google H.A. Riese R.J. Shi G.P. Annu. Rev. Physiol. 1997; 59: 63-88Crossref PubMed Scopus (687) Google Scholar, P.J. Storer A.C. J. Mol. Biol. 1995; 246: 273-283Crossref PubMed Scopus (356) Google Scholar). this peptide in a sequence that the at the processing site of G. J. Mol. Biol. PubMed Scopus Google Scholar). that the signal after this the protein be composed of amino acid The of this sequence with for human cysteine proteinases belonging to the papain family also to a and a mature proteinase sequence as well as to the site protein In fact, as shown in the of mature cysteine proteinases be the amino acid being in all with the active processed form of the novel cysteine proteinase at the residue at with a molecular of the other the amino acid sequence shown in also to the active site residue of the novel protein sequence as well as other important for the of cysteine proteinases, including the and which the of these enzymes (26Berti P.J. Storer A.C. J. Mol. Biol. 1995; 246: 273-283Crossref PubMed Scopus (356) Google Scholar). A analysis of the amino acid these essential revealed a of the novel sequence and that of the cysteine proteinases. the the residue and to the cysteine active site as well as the residue of the characteristic of the of these proteolytic enzymes J. J. Mol. Biol. PubMed Scopus Google Scholar, D. D. Turk D. I. R. Popovic T. Turk V. T. W. J. 1991; PubMed Scopus Google Scholar, R. J. R. Mort J.S. M. J. 1996; PubMed Scopus Google Scholar). the other the a series of and the in the active The protein sequence also of in the mature at and all cysteine proteinases characterized to are it is that at of these has attached the mannose 6-phosphate for lysosomal together all structural we that the isolated cDNA codes for a novel human cysteine proteinase of the papain family that we propose to cathepsin Z, because to this is not used to other of the family. To the chromosomal of the human cathepsin Z we first isolated this gene by a with the full-length cDNA as from of the isolated was in in experiments human chromosome of the cells with specific hybridization of the corresponding to the were mapped to the of chromosome in the be also in other chromosome site was A number of genes have been mapped to this including encoding or J. F. C. R. R. 1984; PubMed Scopus (24) Google Scholar, C. T. H. Y. S. M. T. 1996; PubMed Scopus Google Scholar, H. S. J. PubMed Scopus Google Scholar). However, cysteine proteinase genes of of the different have been to at this chromosome To the isolated cathepsin Z cDNA codes for a functional cysteine we expressed the cloned cDNA in a system the for other cysteine proteinases S. J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar). To we first by a the sequence for the mature cathepsin the sequence of the it was in the of the The called as well as the were into E. coli and the were with analysis of protein from the revealed that the with the recombinant a fusion protein of which was not in the a corresponding to the was in the but not in from the recombinant To the recombinant cathepsin Z, we an in a which was with a and analysis of the protein in the a single of the was To the enzymatic activity of the cathepsin Z, we its degrading activity substrates used for analysis of cysteine proteinases, including and enzymatic revealed that recombinant cathepsin Z a proteolytic activity of the synthetic peptide which is an substrate for different cysteine proteinases R.W. Barrett A.J. Biochem. J. PubMed Scopus Google Scholar). activity was that for cathepsin O in E. coli and the conditions In addition, the proteolytic activity of recombinant cathepsin Z the substrates and was Furthermore, the proteolytic activity of cathepsin Z was by a widely used of this of proteolytic but not by of proteinases and proteinases not these enzymatic that the cloned cDNA codes for a cysteine proteinase with the substrate and characteristic of these proteolytic enzymes. To the of cathepsin Z in human tissues, Northern from a of tissues, including and were with a specific for human cathepsin is from the of the isolated cDNA for this which is the the of with other family the of hybridization with the cathepsin Z a single of was in all distribution of cathepsin Z be with the that it is a lysosomal enzyme involved in the intracellular protein degradation that place in all cell types. Finally, and because have the of different cysteine proteinases in human (8Sloane B.F. Semin. Cancer Biol. 1990; 1: 137-152PubMed Google Scholar, B.F. Dunn J.R. Honn K.V. Science. 1981; 212: 1151-1153Crossref PubMed Scopus (323) Google Scholar, 29Recklies A.D. Poole A.R. Mort J.S. Biochem. J. 1982; 207: 633-636Crossref PubMed Scopus (42) Google Scholar, S. Gottesman M.M. J. Biol. Chem. 1986; Full Text PDF PubMed Google L.J. Gottesman M.M. Cancer Res. 1991; Google Scholar), we the that cathepsin Z could be expressed by human cancer cell lines and primary tumors from different To we first a Northern blot from different cancer cell lines and with the Z cDNA used for the be in a of the was in cancer cell the that cathepsin Z may be also by human In fact, a of different primary tumors for cathepsin Z demonstrated that this gene is widely expressed by tumors from diverse suggesting that cathepsin Z may be to the of proteolytic enzymes with the malignant of human In this we the of a novel human cysteine proteinase called cathepsin We also a structural and functional analysis of this novel enzyme and its of in normal and tumor Finally, we the chromosomal location of the cathepsin Z gene in the human with the that it maps to chromosome which is a unique location for human cysteine proteinase mapped to date. The of cathepsin Z was on a of the human for with to characterized cysteine proteinases. The identified were and used to cDNA from different human finally to the of a full-length cDNA for a protein with sequence to human cysteine proteinases of the papain which was tentatively called cathepsin The identified sequence for this novel enzyme exhibits the characteristic of cysteine proteinases, including a signal a and a for the proteolytic activity of these (26Berti P.J. Storer A.C. J. Mol. Biol. 1995; 246: 273-283Crossref PubMed Scopus (356) Google Scholar). also a series of to be important in the of these enzymes such as the active site residue which is peptide as well as the and which form the of cysteine proteinases J. J. Mol. Biol. PubMed Scopus Google Scholar, D. D. Turk D. I. R. Popovic T. Turk V. T. W. J. 1991; PubMed Scopus Google Scholar, R. J. R. Mort J.S. M. J. 1996; PubMed Scopus Google Scholar). However, a structural analysis of the sequence for cathepsin Z revealed some specific features for this novel this novel cysteine proteinase peptide insertions unique among all family The first of these insertions of the of the to the residue of the is also in the of cathepsin Z and C. and the short this residue from the active site of the cysteine proteinases of the papain family. it is to that it could or the substrate of cathepsin The other insertions of an peptide in the of the and a peptide in the of the but their structural and functional on cathepsin Z the of the sequence of cathepsin Z is its short with in other cysteine proteinases. is well that all cysteine proteinases are synthesized as precursors with an which as an of the proteolytic activity T. E. Mort J.S. Storer A.C. 1992; PubMed Scopus Google Scholar). The has also to be essential for of some cysteine proteinases and for their to in pH K. J. Arch. Biochem. Biophys. 1994; PubMed Scopus Google Scholar, E. E. C. S. Mort J.S. R. 1996; PubMed Scopus Google Scholar). The sequence among the of the different cysteine proteinases are but to structural features, be to groups Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, T. P.J. C. R. R. Storer A.C. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). The first cathepsin enzymes with amino in and called and The the cathepsins B from different and is characterized by a of amino the However, the of cathepsin Z be to of these groups because it is in and Furthermore, this sequence not contain the that in the of different cathepsins have been to as the for the mannose for intracellular of these K. W. J. Biol. Chem. 1995; Full Text Full Text PDF PubMed Scopus Google Scholar). together these structural data, it that the of cathepsin Z from of all characterized family suggesting that it could be a of a different subfamily of enzymes. with this chromosomal location of the cathepsin Z gene has revealed that it maps to chromosome differs from reported for the cysteine proteinase genes of the papain family G. A.C. Munger J.S. Chapman H.A. J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar, S. M. C. 1997; PubMed Scopus Google Scholar, I. Velasco G. López-Otı́n C. 1998; Google Scholar, D. R. Gottesman M.M. J. Biol. Chem. Full Text PDF PubMed Google Scholar, S.J. Steiner D.F. A. Cell Biol. PubMed Scopus Google Scholar, J.R. J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar, S.J. Y. Steiner D.F. Cell 1987; Scholar), additional to the structural that that this novel cysteine proteinase is not to the other of the papain family. In to its in the of of the human cysteine proteinases, of the chromosomal location of the cathepsin Z gene may be in for to in this as demonstrated for cathepsin K Shi G.P. Chapman H.A. R.J. Science. 1996; PubMed Scopus Google Scholar). In this we have also that cathepsin Z is expressed in all normal which a role of this protein as a proteolytic enzyme involved in the normal intracellular protein turnover taking place in all cell types. role of cathepsin Z in human be to that for cathepsins and but this enzyme from a series of cysteine proteinases which appear to play specific roles in in which are or is the of cathepsins and expressed in tissues, and and and to be involved in bone remodeling of activity and of the and processes (20Linnevers C. Smeekens S.P. Bromme D. FEBS Lett. 1997; 405: 253-259Crossref PubMed Scopus (98) Google Scholar, I Velasco G. Cazorla M. Fueyo A. Campo E. López-Otı́n C. Cancer Res. 1998; 58: 1624-1630PubMed Google Scholar, Shi G.P. Chapman H.A. R.J. Science. 1996; PubMed Scopus Google Scholar, R.J. Brömme D. Chapman H.A. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). The analysis of cathepsin Z also revealed a of this enzyme in a series of human cancer cell lines and primary tumors from different that cathepsin Z may be linked to the malignant of human cells as shown for other cysteine proteinases (8Sloane B.F. Semin. Cancer Biol. 1990; 1: 137-152PubMed Google Scholar, L.J. Gottesman M.M. Cancer Res. 1991; Google and a to the of this novel In to the of this human cathepsin Z is a novel of the papain family of cysteine proteinases that with the family characterized to date. The of a series of unique features in its including diverse peptide insertions and an short together with its chromosomal location at 20q13, this enzyme from other cysteine proteinases and that it may be the first representative of a cathepsin The of recombinant cathepsin Z and specific for this proteinase be in the functional of these structural as well as in the role of this novel enzyme in the protein processes in normal and pathological including We M. and J. for and S. for