RECOMBINANT PREPARATION OF CALCITONIN FRAGMENTS AND USE THEREOF IN THE PREPARATION OF CALCITONIN AND RELATED ANALOGS

Abstract: A process for the recombinant preparation of a calcitonin fragment and the use of the fragment in the preparation of calcitonin and related analogs is provided. The process includes recombinantly forming a fusion protein which includes the calcitonin fragment linked to a carbonic anhydrase. The recombinantly formed fusion protein is subsequently cleaved to produce a polypeptide which includes the calcitonin fragment. A method for producing a calcitonin carba analog which includes condensing a desaminononapeptide with the recombinantly formed calcitonin fragment is also provided.

Description: RECOMBINANTPREPARATIONOFCALCITONINFRAGMENTS ANDUSETHEREOFINTHE PREPARATIONOFCALCITONINANDRELATEDANALOGS Calcitonins and related analogs, such as Elcatonin, are known polypeptides which can be employed for treating bone atrophy (see, e.g., U.S. Patent 4,086,221). Naturally occurring calcitonins, such as eel, salmon or human calcitonin, are C-terminal amidated polypeptides which consist of 32 amino acids, the first and the seventh amino acids in each case being L-cysteines whose mercapto groups are connected to each other by the formation of a disulfide bridge. The natural calcitonins can be obtained, for example, by extraction from the mammalian thyroid gland (see, e.g., U.S. Patent 5,428,129). Elcatonin is a modified synthetic "carba" analog of calcitonin whose activity is comparable with that of eel calcitonin (Morikawa et al., Experienta. 32. 1004, (1976)). In contrast to eel calcitonin, Elcatonin lacks an amino terminal end and the disulfide bridge of eel calcitonin has been replaced by a -(CH 2 ) 5 - "carbon bridge." Currently, a variety of processes are known for the preparation of Elcatonin using purely chemical methods. These chemical methods involve condensation ofthe corresponding amino acids or peptides (see, e.g., U.S. 4,086,221 and U.S. 5,428,129). The purely chemical methods, however, all suffer from the disadvantage that, due to the elaborate purification methods required, the Elcatonin is obtained in low yield and its preparation is consequently very expensive. It would accordingly be beneficial to be able to avoid the disadvantages ofthe purely chemical methods in the preparation of Elcatonin through the use of a approach which includes the recombinant preparation of a portion ofthe molecule. This could be achieved, for example, if a simple process for the recombinant preparation of a C-terminal polypeptide fragment was available. The recombinantly synthesized C-terminal fragment could then be used as a starting peptide for the preparation of calcitonin or carba analogs such as Elcatonin. A partially recombinant strategy would also facilitate the synthesis of peptides/peptide analogs of calcitonin, Elcatonin and related analogs or derivatives which could potentially include non-natural amino acids. SUMMARY OF THE INVENTION The present invention is directed to a process for the recombinant preparation of a calcitonin fragment and the use ofthe fragment in the preparation of calcitonin and related analogs including carba analogs (referred to hereinafter as "calcitonin carba analogs"), such as Elcatonin. The invention includes recombinantly forming a fusion protein which includes a target sequence linked to a carbonic anhydrase through a cleavage site. The target sequence includes a sequence of at least about 15 amino acids residues corresponding to a fragment from near the C-terminus of calcitonin or to a closely related analog of such a fragment. Typically, the target sequence includes an amino acid sequence corresponding to amino acids residues 10 through 32 of calcitonin or closely related analogs (collectively referred to hereinafter as a "10-32 fragment"). The recombinantly formed fusion protein is subsequently cleaved with a cleavage reagent to produce a polypeptide including the target sequence. The cleavage reaction may be carried out by contacting the fusion protein with either a chemical cleavage reagent or an enzymatic cleavage reagent. The choice of a suitable cleavage reagent and the corresponding cleavage site incoφorated into the fusion protein will depend on the particular target sequence and carbonic anhydrase sequence present in the fusion protein. Typically, the cleavage reagent and cleavage site are selected such that the amino acid sequence constituting the cleavage site does not appear in the amino acid sequence of either the target sequence or the carbonic anhydrase. For example, a cyanogen bromide cleavage at methionine would not be employed with a fusion protein which included the 10-32 fragment from porcine, bovine or sheep calcitonin. The cleavage site is typically present in a linker sequence which connects the carbonic anhydrase and the target sequence. Alternatively, the fusion protein may include a construct in which the C-terminus ofthe carbonic anhydrase is connected directly to the N-terminus ofthe target sequence. This may occur where the C-terminal residue(s) ofthe carbonic anhydrase and the N-terminal residue(s) ofthe target sequence constitute a cleavage site which allows cleavage ofthe peptide bond between the two fragments. In addition to a cleavage site present in a linker sequence, the carbonic anhydrase portion of the fusion protein may also include a different cleavage site which permits the fusion protein to be cleaved to form a "minifusion protein," i.e., a polypeptide having a C-terminal portion ofthe carbonic anhydrase still linked to the target sequence. One embodiment of the invention includes a method for the recombinant preparation of polypeptides corresponding to amino acids 10-32 of calcitonin or related analogs (" 10-32 fragments"). The method typically includes the recombinant preparation of a polypeptide fragment ("10-32 fragment-Xxx") ofthe formula: A 10 -A| 1 -A 12 -A 13 -A 14 -A I5 -A lo -A ιr A 18 -A 19 -A 2 o-A 2I -A 22 -A 23 -A 24 -A 25 -A 26 -A 27 -Gly- A 29 -A 30 -A 31 -Pro-Xxx (SEQ ID NO: 1) wherein A 10 is Gly or Ser, Ai , is Lys, Thr or Ala, A 12 is Leu or Tyr, A ]3 is Ser, Thr or Trp, A l4 is Gin, Lys or Arg, A )5 is Glu, Asp or Asn, A 16 is Leu or Phe, A 17 is His or Asn, A 18 is Lys or Asn, A, 9 is Leu, Tyr or Phe, A 20 is Gin or His, A 2J is Thr or Arg, A 22 is Tyr or Phe, A 23 is Pro or Ser, A 24 is Arg, Gly or Gin, A 25 is Thr or Met, A 26 is Asp, Ala, Gly, or Asn, A 27 is Val, Leu, He, Phe, or Thr, A 29 is Ala, Val, Pro or Ser, A 30 is Gly, Val or Glu, A 31 is Thr, Val or Ala. The C-terminal -Xxx group is typically a C-terminal carboxylic acid ("-OH"), a C-terminal carboxamide ("-NH 2 "), or group capable of being converted into a C-terminal carboxamide, such as an amino acid residue or a polypeptide group (typically having from 2 to about 10 amino acid residues). The 10-32 fragment represented by residues A 10 to A 32 (SEQ ID NO: 2) corresponds to residues 10 through 32 ofthe amino acid sequences for eel (SEQ ID NO:37), salmon I (SEQ ID NO:38), salmon II (SEQ ID NO:39), salmon III (SEQ ID NO:40), chicken (SEQ ID NO:41), human (SEQ ID NO:42), rabbit (SEQ ID NO:43), porcine (SEQ ID NO:44), bovine (SEQ ID NO:45) and sheep (SEQ ID NO:46) calcitonin or closely related analogs (see the calcitonin sequences shown in Figure 9). The present method may also be employed to recombinantly produce 10-32 fragments corresponding to modified calcitonin sequences. The modified calcitonin sequences may include one or more conservative amino acid substitutions in the natural amino acid sequence. The 10-32 fragment may be utilized in the preparation of calcitonin and related analogs. The preparation typically includes the condensation of an N-terminal fragment of the formula: wherein A 2 is Gly, Ser or Ala; A 3 is Asn or Ser; A g is Val or Met; R 2 is -(CH 2 ) - or -CH(NH 2 )CH 2 S-S-; and Y is OH, OR 1 , where -R 1 is a lower alkyl group; with a recombinantly-f ormed polypeptide of the formula: A 10 -A 11 -A 12 -A 13 -A| 4 -A,5-A, 6 -A 17 -A I8 -A 19 -A 20 -A 2r A 22 -A 23 -A 24 -A 25 -A 26 - A 27 -Gly-A 29 -A 30 -A 3 ,-Pro-Xxx (SEQ ID NO: 1 ) wherein a A 10 is Gly or Ser, A π is wherein A 10 is Gly or Ser, A n is Lys, Thr or Ala, A I2 is Leu or Tyr, A 13 is Ser, Thr or Trp, A ]4 is Gin, Lys or Arg, A, 5 is Glu, Asp or Asn, A )6 is Leu or Phe, A 17 is His or Asn, A, 8 is Lys or Asn, A, 9 is Leu, Tyr or Phe, A 20 is Gin or His, A 21 is Thr or Arg, A 22 is Tyr or Phe, A 23 is Pro or Ser, A 24 is Arg, Gly or Gin, A 25 is Thr or Met, A 26 is Asp, Ala, Gly, or Asn, A 27 is Val, Leu, He, Phe, or Thr, A 29 is Ala, Val, Pro or Ser, A 30 is Gly, Val or Glu, A 31 is Thr, Val or Ala, and -Xxx is -OH, -NH 2 , an amino acid residue or a polypeptide group; in the presence of a non-enzymatic coupling reagent to form a calcitonin- derivative having the formula: A 13 -A, 4 -A 15 -A 16 -A 17 -A 18 -A 19 -A 2 o-A 21 -A 22 -A 23 -A 24 -A 2 s-A 26 -A 27 -Gly-A 29 - A 30 -A 31 -Pro-Xxx. (SEQ ID NO:48) In one embodiment ofthe invention, the recombinantly-formed 10-32 fragment is condensed with a desaminononapeptide. The desaminononapeptide is a carba analog of an N-terminal calcitonin fragment and typically has the formula: C(O)-A 2 -A 3 -Leu-Ser-Thr-NH-CH-C(O)-Ag-Leu-Y CH 2 (CH 2 ) 3 — CH 2 (SEQ ID NO:3) wherein A 2 is Gly, Ser or Ala; A 3 is Asn or Ser; A g is Val or Met; and Y is OH, OR 1 , where -R 1 is a lower alkyl group (i.e., a C r C 6 alkyl group). The condensation reaction may be carried out using a chemical coupling reaction such as those described in U.S. 4,086,221 and U.S. 5,428,129, the disclosures of which are herein incoφorated by reference. Chemical coupling agents are well known to those skilled in the art. Suitable chemical coupling agents include carbodiimides and a variety of other non-enzymatic reagents capable of reacting with the α-carboxylic acid group of a peptide to form an activated carboxylic acid derivative α-carboxylic acid derivative with an N-terminal α-amino group of another amino acid or polypeptide. Chemical coupling reactions in which the C-terminal α-carboxylic acid ofthe desaminononapeptide has been converted to an acid azide, mixed acid anhydride, acid imidazole or active ester may be employed in the present invention. An especially effective method of coupling two peptide fragments is carried out in the presence of a carbodiimide and a reagent capable of forming an active ester, e.g., a mixture of dicyclohexylcarbodiimide ("DCC") and either N- hydroxysuccinimide ("HOSu") or 1-hydroxybenzotriazole ("HOBt"). The recombinantly-formed 10-32 fragment employed in the condensation preferably has the formula: A 10 -A n -Ai 2 -A 13 -A 14 -A 15 -A 16 -A 17 -A 18 -A 19 -A 20 -A 2r A 22 -A 23 -A 24 -A 25 -A 26 - A 27 -Gly-A 29 -A 30 -A 31 -Pro-Xxx (SEQ ID NO: 1) wherein A, 0 through A 31 and -Xxx are as defined herein. The product ofthe coupling reaction is typically a calcitonin carba analog having the formula: C^-A Aa-Leu-Ser-Thr-NH-CH-C^-Ag-Leu-A^-Aπ-A^- CH 2 (CH 2 ) 3 CH 2 A| 3 -A 14 -A 15 -A 16 -A I7 -A 18 -A 19 -A 20 -A 2r A 22 -A 23 -A 24 -A 25 -A 26 -A 27 -Gly-A 29 - A 30 -A 31 -Pro-Xxx (SEQ ID NO:4) wherein A ]0 through A 31 and -Xxx are the same as defined herein for the desaminononapeptide (SEQ ID NO:3) or the 10-32 fragment-Xxx (SEQ ID NO: 1 ). The coupling ofthe desaminononapeptide and the recombinantly-formed peptide is typically carried out in the presence of a non-enzymatic coupling reagent. A preferred embodiment ofthe invention provides a method for the recombinant preparation and amidation of a polypeptide fragment (referred to herein as the "ECF2- amide") having the formula: Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr- Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-NH 2 (SEQ ID NO:6) and for coupling the ECF2-amide to an amino terminal fragment of Elcatonin (referred to hereafter as "ECF1"), which has the formula: The present invention also provides a nucleic acid sequence which includes a sequence coding for amino acids 10-32 of calcitonin or a related analog. The nucleic acid sequence typically encodes a fusion protein which includes the 10-32 fragment linked to a carbonic anhydrase through a cleavage site. The portion ofthe gene encoding the 10-32 fragment is preferably designed using optimal codon usage for a targeted host cell, such as E. coli, S. cerevisiae or P. pastoris. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a map of plasmid pET31FlmhCAII. The plasmid includes the FI origin of replication from plasmid pEMBL8 introduced in the opposite orientation ofthe pSP65 origin of replication. Figure 2 shows a map of plasmid pABN. Plasmid pABN includes a nucleic acid sequence (SEQ ID NO:47 and SEQ ID NO:48) coding for a Linker peptide fragment (SEQ ID NO: 49) inserted into the plasmid near the carboxy terminal end ofthe gene sequence of human carbonic anhydrase II ("hCAH"). Figure 3 shows a map of plasmid pTBN. Plasmid pTBN is a tetracycline resistant expression vector derived from the insertion of a 1.5-kb fragment from pABN into plasmid pBR322. The 1.5-kb fragment includes the T7 promotor, hCAII, Linker and T7 terminator sequences from pABN. Figure 4A is a schematic illustration ofthe first step ofthe preparation using PCR methodology of a nucleotide sequence encoding ECF2-Ala and additional restriction sites to permit cloning the fragment into plasmids. This step was carried out by conducting a PCR reaction using Taq DNA polymerase on PCR MIX 1. Figure 4B is a schematic illustration ofthe second step ofthe preparation of a DNA sequence encoding ECF2-Ala. The PCR products derived from the extension of oligonucleotides 2 and 3 in PCR MIX 1 (2 Ext (SEQ ID NO:8) and 3 Ext (SEQ ID NO:50) respectively) have 20 bp of complementary sequence at their 3' ends. The second PCR reaction using Taq DNA polymerase creates a double stranded nucleotide fragment which includes a full length non-interrupted gene sequence encoding ECF2-Ala (SEQ ID NO:9). Figure 5 shows a map of plasmid pTBN26. Plasmid pTBN26 includes a gene sequence for the entire hCAII-Linker-ECF2-Ala ("hCA-ECF2-Ala") fusion protein construct. Figure 6A shows the nucleotide (SEQ ID NO: 11) and amino acid (SEQ ID NO: 12) sequences for the N-terminal methionine and hCAII residues 1 -162 ofthe hCAII- Linker-ECF2-Ala fusion protein construct. Figure 6B shows the nucleotide (SEQ ID NO: 11 ) and amino acid (SEQ ID NO: 12) sequences for hCAII residues 162-257, and the linker and ECF2-Ala fragments ofthe hCAII-Linker-ECF2-Ala fusion protein construct. Figure 7 shows a nucleotide sequence (SEQ ID NO:5) and the amino acid (SEQ ID NO:6) sequence for the 23 amino acid C-terminal fragment ("ECF2") of Elcatonin and eel calcitonin. The nucleotide sequence shown is the sequence encoding ECF2 present in the gene for the hCA-ECF2-Ala fusion protein incoφorated into plasmid pTBN26. Figure 8 shows a representative preparative HPLC trace (using a polysulfolethyl- aspartamide column) of a sample containing ECF2-amide (SEQ ID NO: 6). The peak for ECF2-amide appears between 14.5 and 16.3 minutes. Figure 9 A shows the amino acid sequences for residues 1-15 of calcitonin from a number of species. Figure 9B shows the amino acid sequences for residues 16-32 of calcitonin from a number of species. Figure 10 shows a double stranded DNA fragment (SEQ ID NO:9) synthesized from the 5 oligonucleotide described in example 1.1 via PCR methodology and the peptide sequence encoded by the double stranded DNA fragment (SEQ ID NO: 10). Figure 11 depicts the nucleotide sequence for oligonucleotide 2 (SEQ ID NO:8) produced during the PCR synthesis ofthe gene sequence encoding ECF2. Figure 12 depicts the nucleotide sequence for oligonucleotide 3 xt (SEQ ID NO:50) produced during the PCR synthesis ofthe gene sequence encoding ECF2. DETAILED DESCRIPTION OF THE INVENTION The recombinant preparation ofthe fusion protein according to the present invention includes the construction of a nucleic acid sequence coding for the target sequence linked to a carbonic anhydrase through a cleavage site ("FP nucleic acid sequence"). The FP nucleic acid sequence shown in Figure 6 is one example of a suitable nucleic acid sequence for use in the present method. The nucleic acid sequence shown in Figure 6 includes codons encoding residues 1-257 of human carbonic anhydrase II ("hCAII"). Inclusion of this amino acid sequence or other functionally active fragments of a carbonic anhydrase in the fusion protein greatly facilitates the isolation ofthe fusion protein from cell debris. As used herein, the term "carbonic anhydrase" includes naturally occurring carbonic anhydrase (and any allelic variants), functionally active carbonic anhydrase fragments or modified versions ("mutants") thereof. Herein "functionally active carbonic anhydrase fragments and mutants" means a fragment or modified version of a carbonic anhydrase which exhibits the enzyme inhibitor binding properties of hCAII. Fragments having such properties are capable of binding carbonic anhydrase inhibitors such as sulfanilamides extremely tightly. A functionally active fragment having such binding properties exhibits highly selective affinity binding to a low molecular weight ligand, e.g. a sulfanilamide, or a synthetic derivative thereof. The binding is strong so that, in general, the carbonic anhydrase/ligand conjugate will exhibit a solution dissociation constant (inverse ofthe binding constant) of no more than about 10 "7 M. Generally, the ligand is a reversible inhibitor for the carbonic anhydrase. Suitable carbonic anhydrase fragments may lack an N-terminal or C-terminal portion ofthe enzyme, so long as the fragments retain the functional inhibitor binding activity ofthe enzyme. Similarly, modified carbonic anhydrases which may be employed as binding proteins in the present fusion protein may be modified by one or more amino acid additions, deletions or insertions so long as the modified enzyme substantially exhibits the inhibitor binding activity described above. Typically, a carbonic anhydrase is modified by deleting or altering amino acid residues so that the modified enzyme does not contain the particular amino acid(s) to be employed as a cleavage site in the fusion protein. For example, where cyanogen bromide is to be utilized as a cleavage reagent, a carbonic anhydrase may be modified to remove or replace any methionine ("Met") residues normally present. The FP nucleic acid sequence includes a sequence encoding a 10-32 fragment, i.e., amino acid residues 10-32 of calcitonin or a closely related analog. The closely related analogs may be derived from conservative amino acid substitutions in a calcitonin 10-32 fragment. This portion ofthe nucleic acid sequence may be designed to optimize the expression ofthe fusion protein in a particular host cell. For example, where the expression ofthe fusion protein is to be carried out using an enterobacteria such as E. coli as the host organism, the nucleic acid sequences encoding the 10-32 fragment and the cleavage site are typically constructed based on the frequency of codon usage for the targeted host organism (see, e.g., discussion of frequency of codon usage in Gribskov et al., Nucl. Acids Res..12, 539-549 (1984)). The cleavage site may be a chemical cleavage site or an enzymatic cleavage site. Chemical and enzymatic cleavage sites and the corresponding agents used to effect cleavage of a peptide bond close to one of these sites are described in detail in PCT patent application WO 92/01707, the disclosure of which is herein incoφorated by reference. Examples of peptide sequences (and DNA gene sequences coding therefor) suitable for use as cleavage sites in the present invention and the corresponding cleavage enzymes or chemical cleavage conditions are shown in Table 1. The gene sequence indicated is one possibility coding for the corresponding peptide sequence. Other DNA sequences may be constructed to code for the same peptide sequence. Preferably, the nucleic acid sequence coding for the cleavage site is designed based on the more commonly used codons for each amino acid for the host cell to be employed in the expression ofthe fusion protein. For example, The nucleotide sequence may be based on optimum codon usage for an enterobacteria, such as E. coli (see, e.g., Gribskov et al., Nucl. Acids Res.. 12. 539-549 (1984)). The cleavage site may be present as part of a linker peptide which connects the carbonic anhydrase and the target sequence. For example, the amino acid sequence (SEQ ID NO: 12) for hCAII-linker-ECF2-Ala ("hCA-ECF2-AIa") depicted in Figure 6 includes a seven amino acid linker sequence (-Phe- Val- Asp- Asp- Asp- Asp- Asn-; (SEQ ID NO: 14)) which sets up a chemical cleavage site cleavable by hydroxylamine ("Asn-Gly") between the C-terminal asparagine residue ofthe linker and the N-terminal glycine residue ofthe target sequence. Table 1 Enzymes Peptide for Cleavage Sequence DNA Sequence Enterokinase (Asp) 4 Lys GACGACGACGATAAA (SEQ ID NO: 16) (SEQ ID NO: 15) Factor Xa IleGluGlyArg ATTGAAGGAAGA (SEQ ID NO: 18) (SEQ ID NO: 17) Thrombin GlyProArg or GGACCAAGA or GlyAlaArg GGAGCGAGA Ubiquitin Cleaving ArgGlyGly AGAGGAGGA Enzyme Renin HisProPheHisLeu- CATCCTTTTCATC- LeuValTyr TGCTGGTTTAT (SEQ ID NO:20) (SEQ ID NO: 19) Trypsin Lys or Arg AAA OR CGT Chymotrypsin Phe or Tyr or Tφ TTT or TAT or TGG Clostripain Arg CGT S. aureus V8 Glu GAA Chemical Peptide Cleavage Sequence DNA Seqence (at pH3) AspGly or AspPro GATGGA or GATCCA (Hydroxy lamine) AsnGly AATCCA (CNBr) Methionine ATG BNPS-skatole Tφ TGG 2-Nitro-5- Cys TGT thiocyanatobenzoate The fusion protein includes at least one copy and may include multiple copies of the target sequence. Where multiple copies ofthe target sequence are present, the copies may be tandemly linked together. Alternatively, the copies ofthe target sequence may be linked together by an innerconnecting linker peptide. The innerconnecting linker peptide may be the same as or different than the intraconnecting linker peptide which connects the carbonic anhydrase to the first copy ofthe target peptide. If the innerconnecting and intraconnecting linker peptides are the same or include the same cleavage site, the fusion protein may be cleaved directly to produce a number of fragments each containing a single copy ofthe target peptide. If, however, the innerconnecting and intraconnecting linker peptides contain different cleavage sites, it may be possible to initially cleave off the carbonic anhydrase fragment to form a intermediate polypeptide having more than one copy ofthe target peptide. Target sequences free of methionine residues may be produced using the present method from a multicopy construct having innerconnecting peptides which include a methionine residue. Where the methionine residue is directly linked to the C-terminus of the target sequence, the multicopy construct may be cleaved with cyanogen bromide. The resulting fragments may be transpeptidated using a carboxypeptidase, e.g., a serine carboxypeptidase such as carboxypeptidase Y, to replace the C-terminal homoserine residue with an α-amidated amino acid. The fragments may be also transamidated with the carboxypeptidase to replace the C-terminal homoserine residue with a 2- nitrobenzylamine compound. This produces a fragment having a C-terminal (2-nitrobenzyl)amido group which may be photochemically decomposed to produce an α-amidated peptide fragment minus the homoserine residue. One example of a fusion protein including multiple copies of a target sequence in a construct which includes hCA-(MetValAspAspAspAspAsn-ECF2) n -Xxx, where hCA, ECF2 and Xxx are as defined herein and n is an integer (typically 2 to 20). Such a construct may be treated with CNBr to form ValAspAspAspAspAsn-ECF2-Hse (SEQ ID NO:49) peptide fragments (where Hse is a homoserine residue produced by the reaction of CNBr with a Met residue). The peptide fragments may then be reacted with a nucleophile such as o-nitrophenylglycine amide ("ONPGA") in the presence of a peptidase such as carboxypeptidase Y resulting in the replacement ofthe Hse residue by ONPGA. Upon photolysis, the transpeptidation product is converted to a C-terminal carboxamide. The N-terminal tail sequence, ValAspAspAspAspAsn (SEQ ID NO:50), may be cleaved off the fragments by treatment with hydroxylamine. A preferred embodiment ofthe invention is directed to the preparation ofthe C-terminal eel calcitonin polypeptide fragment, ECF2-amide (SEQ ID NO:6). The preparation involves the initial genetic expression ofthe following protein construct: Met-hCAir-Met 240 -Val 24r hCAir , -Linker-ECF2-aa ("hCA-ECF2-aa") where aa is an amino acid residue and Met is the required N-terminal residue of any E. coli protein. The Met residue is added to the N-terminus ofthe first residue of hCAII' (a 239 amino acid N-terminal polypeptide segment of human carbonic anhydrase II), Met 240 - Val 24 ι is the only cyanogen bromide labile peptide bond in human carbonic anhydrase II ("hCAII"), hCAII" is a 16 amino acid fragment (SEQ ID NO:21) from near the C-terminal end of hCAII (residues 242-257). The C-terminal amino acid residue of ECF2-aa (SEQ ID NO:22), designated aa, provides an amidation signal to enable conversion to the Pro-amide that constitutes the C-terminus of Elcatonin (SEQ ID NO: 13). The aa residue is typically an amino acid residue, such as alanine, which is capable of being exchanged with a nucleophile via a transamidation reaction. The desired product, ECF2-aa (SEQ ID NO: 22), can be obtained from a hCA- ECF2-aa protein construct, in at least two ways. The first employs a cleavage of hCA- ECF2-aa at the Asn-Gly bond with hydroxylamine to yield ECF2-aa (SEQ ID NO:22) directly. Alternatively, cleavage with cyanogen bromide (CNBr) yields a minifusion protein which includes the hCAH" C-terminal fragment (SEQ ID NO:21) of hCAII linked to the ECF2-aa polypeptide (SEQ ID NO:22). The minifusion protein may subsequently be cleaved with hydroxylamine either before derivatization to provide ECF2-aa (SEQ ID NO:22) or, after derivatization ofthe minifusion protein side chain residues, e.g., where the Lys residues of ECF2-aa (SEQ ID NO:22) have been derivatized to form Lys residues having Z-protected side chain amino groups. In the case where derivatization reagents modify the side chain amino functions of Lys, then after cleavage of derivatized minifusion protein, the resulting protected ECF2-aa (SEQ ID NO:22) produced will only possess a single free amino function at the alpha position ofthe N-terminal glycine residue. The free N-terminal α-amino group can be used for subsequent specific chemical reactions, such as coupling to the C-terminal residue of ECF1 (SEQ ID NO:7) to provide Elcatonin (SEQ ID NO: 13). Coupling reactions of this type may be carried out after the ECF2-aa polypeptide (SEQ ID NO:22) has been converted to an ECF2 derivative having a C-terminal residue Pro-amide ("ECF2-amide"; (SEQ ID NO:6)), or may be employed to produce derivatized forms of Elcatonin (e.g., "Elcatonin-aa"; (SEQ ID NO:30)) for subsequent conversion to Elcatonin (SEQ ID NO: 13). A preferred sequence of ECF2-aa is: Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asp-Val- Gly-Ala-Gly-Thr-Pro-Ala ("ECF2-Ala"; SEQ ID NO:23) The ECF2-Ala peptide fragment may be derived from cleavage of a hCA-ECF2- Ala protein construct, e.g., by treatment with hydroxylamine. The hCA-ECF2-Ala protein construct may include the sequence: hCAir-Met-Val-Asp-Asn-Tφ-Arg-Pro-Ala-Gln-Pro-Leu-Lys-Asn-Arg-Gln-Ile- Lys-Ala-Phe-Val-Asp-Asp-Asp-Asp-Asn-Gly-Lys-Leu-Ser-Gln-Glu-Leu-His- Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala (SEQ ID NO: 12) Alternatively, the hCA~ECF2-Ala protein construct may be cleaved at a different bond to produce a pre-ECF2-Ala peptide, i.e., a minifusion protein. For example, the hCA-ECF2-Ala protein construct may be cleaved to produce a pre-ECF2-Ala peptide which includes a C-terminal fragment of hCAII or a modified version thereof linked to the N-terminus of ECF2-Ala (SEQ ID NO:23). In a preferred embodiment ofthe invention, the hCA-ECF2-Ala protein construct (SEQ ID NO: 12) may be cleaved with cyanogen bromide (CNBr) to yield a minifusion protein ("MFP") having the amino acid sequence: Val-Asp-Asn-Tφ-Arg-Pro-Ala-Gln-Pro-Leu-Lys-Asn-Arg-Glu-Ile-Lys-Ala-Phe- Val-Asp-Asp-Asp-Asp-Asn-Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln- Thr-Tyr-Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala (SEQ ID NO:24). The MFP includes the Val 241 -hCAII" fragment from the C-terminal end of hCAII: Val-Asp-Asn-Tφ-Arg-Pro-Ala-Gln-Pro-Leu-Lys-Asn-Arg-Glu-Ile-Lys-Ala (SEQ ID NO:25) and a Linker sequence having the formula: Phe-Val-Asp-Asp-Asp-Asp-Asn (SEQ ID NO: 14). The polypeptide segment hCAir-Met 24 o-Val 24 ]-hCAir of human carbonic anhydrase II (hCAII) has been reported in Biochemistry, 9_, 638 (1970) and can be used as the binding protein segment for purification of a carbonic anhydrase-ECF2-aa protein construct using procedures such as those described in (WO 92/01707). In accordance with WO 92/01707, carbonic anhydrase fragments or modified carbonic anhydrases can also be used as the binding protein segment. The amino acid sequences for a number of other carbonic anhydrases have also been reported (see, e.g., Hewett-Emmett et al., in The Carbonic Anhydrases. Dodgson et al. eds., Chapt. 2, pp. 15-32 (1991)). If the amino acid sequence of a particular carbonic anhydrase is known but no gene is available, a cDNA coding for the carbonic anhydrase may be isolated using procedures well known to those skilled in the art (see, e.g., Sambrook et al., Molecular Cloning. A Laboratory Manual. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. (1989), and Tanhauser et al., Gene. 1 17. 113-117 (1992)). This process typically includes constructing nucleic acids probes (e.g., about 20- 30 base pairs in length) coding for fragments ofthe carbonic anhydrase in question. Degenerate nucleotide probes based on the known amino acid sequence or related DNA sequence can be used to screen a cDNA library (see, e.g., Wallace et al., Nucleic Acids Res., 6_, 3543 (1979) and Wallace et al., Nucleic Acids Res.. 9_, 879 (1981)). In another embodiment ofthe invention, the target sequence may include an amino acid sequence in which at least one ofthe C-terminal residues of a 10-32 fragment has been replaced by one or more amino acid residues ("leaving unit"). The C-terminal end of the target sequence may be modified via a transpeptidation reaction, either before or after cleavage of me fusion protein to remove the carbonic anhydrase portion. The transpeptidation reaction typically results in the removal ofthe leaving unit from the C-terminal end ofthe target sequence and its replacement by the missing C-terminal residue (or residues) ofthe "10-32 fragment." For example, a recombinantly produced peptide having C-terminal leaving unit, such as eel(10-30)-Ala (amino acid residues 10-30 of eel calcitonin coupled to a C-terminal alanine), may be transpeptidated using S. aureus V8 to introduce a Thr-Pro-NH 2 dieptide after residue Glu 30 in place ofthe C-terminal Ala residue. In addition to being employed in the preparation of carba analogs of calcitonin. such as Elcatonin, the recombinantly synthesized 10-32 fragments ofthe present invention may be used in the synthesis of calcitonins. For example, a side chain protected derivative of ECF2-amide, e.g., where Ser, Thr and Glu residues are protected as benzyl ethers or esters and Lys residues are protected by a CBZ group, may be coupled using a non- enzymatic coupling reagent with the cyclic oxidized form of residues 1-9 of eel calcitonin. Examples of suitable non-enzymatic coupling reagents which may be used to carry out the coupling reaction include DCC, N-ethyl-N'-dimethylaminopropyl-carbodiimide ("EDAPC"), DCC/HOSu, DCC/HOBt and EDAPC/HOSu (see, e.g., U.S. 5,429,129, the disclosure of which is herein incoφorated by reference). I. Recombinant Formation of he Fusion Protein a. Vectors Expression vectors incoφorating the fusion protein gene are chosen to be compatible with the host cell. The vectors used have many features in common. These features include an origin of replication compatible with the host cell, regulatory DNA sequences for transcription and regulation of transcription (for inducible systems), an efficient ribosomal binding site (for prokaryotic hosts), a poly-A signal (for eukaryotic hosts). In addition, phenotype genes, regulatory regions and leader sequences may be included. Prokaryotic vectors such as those for expression in E. coli aie characterized by an origin of replication, a genetic marker (phenotype) for selection of transformed bacteria, and DNA regulation sequences that will direct the expression ofthe gene of interest. The regulation sequences typically will include a promoter to drive the transcription, an operator to control transcription (on/off switch), an efficient ribosome binding site to start translation, and a transcription termination signal. The start and stop codons are provided by the inserted (fusion protein) gene. Prokaryotic vectors in particular contain a suitable "expression cassette" which is based upon any of a number of available promoter/operator systems. Typical promoters for inclusion in the prokaryotic vector include lactose, tryptophan, T7, lipoprotein, alkaline phosphatase, lambda leftward or rightward promoter or a combination of these (hybrid promoters). The lactose and tryptophan operators, as well as temperature sensitive lambda promoters are typical on/off switches that can be included in the prokaryotic vector. Typical phenotypic markers for inclusion in the prokaryotic vector include genes for development of resistance to ampicillin, tetracycline, kanamycin, and chloramphenicol. Eukaryotic vectors such as those for expression in the yeast, Saccharomyces cerevisiae, typically are shuttle vectors which contain an origin of replication for E. coli and one for S. cerevisiae, a genetic marker for both cell types, and DNA regulation sequences that will direct the expression in yeast. The regulation sequences typically include a promoter, a regulatory sequence, and a transcription termination signal (including a polyadenylation signal). Optional signal sequences for direction of cellular secretion can also be inserted into the eukaryotic vector. Typical markers to be incoφorated provide positive selection by complementation of mutations in the genes necessary for production of uracil, leucine, histidine, adenine, tryptophan and the like. Promoter sequences which preferably can be incoφorated into the eukaryotic vector include alcohol dehydrogenase I or II, glyceraldehyde phosphate dehydrogenase, phosphoglycerokinase, galactose, tryptophan, mating factor alpha and the like. Depending on the nature ofthe vector selected, the ECF2-aa gene fragment can be expressed in a variety of organisms. Both vectors having a specific host range and vectors having a broad host range are suitable for use in the present invention. Examples of vectors having a specific host range, e.g. for E. coli, are pBR322 (Bolivar et al., Gene.2, 95-113, 1977), pUC 18/19 (Yanisch Perron et al., Cene, II, 103-119, 1985), pK18/19 (Pridmore, Gene. 5^, 309-312, 1987), pRK290X (Alvarez-Morales et al., Nucleic Acids Res..14, 4207-4227, 1986) and pRA95 (obtainable from Nycomed Pharm a AS, Huidove, Denmark). Other vectors that can be employed are "broad host range" vectors which are suitable for use in Gram negative bacteria. Examples of such "broad host range" vectors are pRK290 (Ditta et al, Proc.Nat.Acad.Sci.. ZZ, 7347-7351, 1980), pKT240 (Bagdasarian et al., Gene.26, 273-282, 1983), derivatives of pRK290, such as pLAFRl (Long et al., Nature. 2j_9_, 485-488, 1982), derivatives of pKT240, such as pMMB66EH (Furste et al., Gene. 48. 1 19-131, (1986)) or pGSS33 (Shaφe, Gene, 22, 93-102, (1984)). h rnnstmction of Plasmid PTBN An expression vector, pET 1FlmhCAII, containing the hCAII gene was obtained from Dr. P.J. Laipis at the University of Florida. The ampicillin resistant, T7 expression vector was constructed by the method described in Tanhauser et al., Gene. 1 17. 1 13-1 17 (1992) from the plasmid pET-3c (Studier et al., Methods Enzymol.. 185. 60-89 (1990)). The T7 expression cassette from the pET-3c vector was transferred to a truncated pSP65 plasmid. To enable the production of single stranded plasmid DNA, the FI origin from pEMBL8+ (Dente et al., Nucleic Acids Res., ϋ, 1645-1655 (1983)) was ligated into the Bgl II restriction site ofthe positive clones. The resulting plasmid was designated pET3 lFlm, where Flm indicates that the FI origin has the opposite orientation ofthe pSP65 origin of replication. Finally, human carbonic anhydrase II cDNA (hCAII cDNA) was cloned into the pET31Flm plasmid between the Nde± and BamH I sites to give a plasmid designated as pET31 F 1 mhCAII (see Figure 1 ). The Linker region ofthe plasmid was created by first synthesizing two complementary oligonucleotides at the DNA Synthesis Core Facility ofthe Interdisciplinary Center for Biotechnology at the University of Florida: 5'AGCTTTCGTTGACGACGACGATATCTT3' (SEQIDNO:26) 5'AGCTAAGATATCGTCGTCGTCAACGAA3' (SEQIDNO:27) The oligonucleotides were phosphorylated, annealed and ligated into the Hind III site near the carboxy terminal end ofthe gene sequence of hCAII. Plasmids containing the insert have a unique EcoR V site immediately following the fourth aspartic acid residue in the polypeptide fragment, Linker (SEQ ID NO: 14). The resulting plasmid is referred to as pABN (see Figure 2). The plasmids pABN and pBR322 (Bolivar et al. Gene. 2, 95-113 (1977) were used to construct a tetracycline resistant expression vector to be used for the production of ECF2-aa (SEQ ID NO:27), e.g., where aa is Ala. The 1.5-kb Ssp I/BspE I fragment from pABN was inserted into the Seal site of pBR322 resulting in pTBN (see Figure 3). c. Host Strains and Transformation Procedures for methods to restrict, ligate, transform, select, culture, and lyse according to the invention, generally follow standard methods known in the art. Literature providing the details for these methods include, Sambrook et al., Molecular Cloning. A Laboratory Manual. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. (1989), the disclosure of which is incoφorated herein by reference. In order to prepare the production strains for the fermentation, the DNA fragment encoding hCA-ECF2-aa is introduced into a host strain suitable for the expression of an hCA-ECF2 fusion protein. Examples of microorganisms which are suitable for expressing this gene typically include strains possessing a high tolerance of substrate and starting material, are enterobacteria, such as from the genus Escherichia. Microorganisms ofthe species E. coli are particularly prefened. The microorganisms can contain the hCA- ECF2-aa DNA fragment either on a vector molecule or integrated in their chromosomes. The selected microorganisms are transformed using methods well known to those skilled in the art (see, e.g. Sambrook et al., cited supra) with a vector containing the hCA-ECF2- aa DNA fragments. Examples of suitable production strains are E. coli JMl 09 (DE3) and E. coli BL21 (DE3), in each case containing a plasmid encoding the fusion protein, e.g., pTBN26. The eukaryotic cells may include unicellular organisms, such as yeast cells, as well as immortal cells from higher organisms, such as plant, insect or mammalian cells. Suitable eukaryotic host cells include Saccharomyces cerevisiae, Pichia pastoris, Aspergillus niger, Spodoptera frupiperda, and corn, tobacco or soybean plant cells. The higher organisms useful as hosts include higher order plants and animals having germ cells that are amenable to transformation. Included are plants such as tobacco, corn, soybean and fruit bearing plants, and invertebrate and vertebrate animals such as fish, birds and mammals, such as sheep, goats, cows, horses and pigs. The transformed host strains are typically isolated from a selective nutrient medium to which an antibiotic has been added against which the host strains are resistant due to a marker gene located on the vector. d. Fermentation The recombinant preparation of the hCA-ECF2-aa fusion protein is carried out using the microorganisms which contain the hCA~ECF2-aa DNA fragment and/or the vector plasmids (containing hCA~ECF2-aa fragment). The process may be carried out by methods which are known per se, for example, by the method described in WO 92/01707. In accordance with this, commercially available growth media, such as Luria broth, can be used. The fermentations are batch fed with oxygen and amino acid supplementation to provide high cell densities. After the fermentation is complete, the microorganisms may be disrupted as described in WO 92/01707 and the hCA-ECF2-aa fusion protein purified, e.g., using sulfanilamide affinity chromatography as described in WO 92/01707. II. Cleavage of the Fusion Protein to Yield ECF2-Ala A fusion protein having the sequence shown below may be cleaved between the amino acids Asn 7 (amino acid 7 ofthe linker sequence) and Gly A 10 (amino acid 1 of ECF2-Ala) as indicated by the "*" below. hCAir-Met-Val-Asp-Asn-Tφ-Arg-Pro-Ala-Gln-Pro-Leu-Lys-Asn-Arg-Gln-Ile- Lys-Ala-Ser-Phe-Val-Asp-Asp-Asp-Asp-Asn*-Gly-Lys-Leu-Ser-Gln-Glu-Leu- His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala (SEQ ID NO: 12) Specific cleavage at this site can be achieved by treatment with hydroxylamine. The resulting ECF2-Ala fragment (SEQ ID NO:23) may be purified by conventional procedures. III. Amidation of ECF2-aa fSEO ID NO:22 to Form ECF2- mide (SEO ID NO:6 The amidation of ECF2-aa (SEQ ID NO:22) may be carried out in accordance with WO 92/05271, by transamidating an ECF2-aa peptide such as ECF2-Ala (SEQ ID NO:23) with a nucleophilic amino compound in the presence of carboxypeptidase Y (see Scheme 1 below) to form a peptide intermediate capable of being reacted or decomposed to form ECF2-NH 2 (SEQ ID NO:6). Examples of suitable nucleophiles include o- nitrobenzylamines, such as o-nitrophenylglycine amide ("ONPGA"). The transamidation results in a replacement ofthe C-terminal -aa residue of ECF2-aa (SEQ ID NO:22) by the nucleophilic amine. Photolysis ofthe resulting photolabile intermediate, e.g., ECF2- ONPGA (SEQ ID NO:28), leads to cleavage ofthe nucleophile and the production of an ECF2 fragment having an amidated proline at the carboxy terminus ("ECF2-amide"; SEQ ID NO:6). The ECF2-amide may be purified by conventional methods. SCHEME 1 ECF2-aa + ONPGA ECF2-ONPGA (SEQ ID NO:22) CPD-Y (SE.Q ID NO:28) light ECF2-amide (SEQ ID NO:6) IV. Condensation of Elcatonin-Frayment 1 fECFI) and ECF2-Amide The N-terminal Elcatonin fragment ECFl (SEQ ID NO:7) and the Elcatonin related fragment ECF2-Xxx (SEQ ID NO: 1) may be coupled using standard peptide coupling reactions as described herein, e.g., in the presence of DCC/HOSu, EDAPC/HOSu or DCC/HOBt. If the coupling reaction is carried out using unprotected forms of ECFl and ECF2-amide, the C-terminal α-carboxylic acid ofthe ECFl fragment is typically converted into an activated ester prior to the addition ofthe ECF2 fragment. The Elcatonin (SEQ ID NO: 13) produced by the coupling reaction may be purified by conventional techniques, such as preparative HPLC methods. Carba-analogs of other calcitonins (e.g. salmon I calcitonin (SEQ ID NO:38)) and related calcitonin carba analogs may be prepared in a similar manner using ECF 1 (SEQ ID NO:7) and other 10-32 fragments, e.g., the salmon I calcitonin 10-32 fragment (SEQ ID NO:29). The present invention also allows the preparation of carba analogs through the combination ofthe C-terminal fragment of a calcitonin from one species with an N-terminal carba fragment corresponding to a calcitonin from a different species. SCHEME 2 C(O)-Ser-Asn-Leu-Ser-Thr-NHCHC(O)-Val-Leu-OH (CH 2 ) 5 (SEQ ID NO:7) + Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr- Tyr-Pro-Arg-Thr-Asp-V ent Elcatonin (SEQ ID NO: 13) V, Cleavage ofthe Fusion Protein hCA-ECF2-aa to Give the Minifusion Protein flVIFPV In another embodiment ofthe invention which employs a chemical coupling reaction in the formation of Elcatonin (SEQ ID NO: 13), the Met-hCAH'-Met 240 -Val 24 , - hCAH"-Linker-ECF2-Ala fusion protein (SEQ ID NO: 12) may be cleaved between the Met 240 and Val 241 residues via CNBr treatment to yield a 48 amino acid minifusion protein (Val 241 -hCAH"-Linker-ECF2-Ala, hereinafter "MFP" (SEQ ID NO:24)). The MFP is composed of 3 constituent fragments. The amino terminal portion ofthe minifusion protein essentially constitutes a 24 residue "biological blocking group" on the N-terminus ofthe ECF2-Ala fragment (SEQ ID NO:23). The MFP (SEQ ID NO:24) may be purified by conventional procedures and subsequently derivatized to protect amino acid side chain residues. VL Introduction of Protective Groups into a Minifusion Protein. When ECF2-aa (SEQ ID NO:22) is to be isolated in a chemically blocked form, a minifusion protein may be separated from the fusion protein following cleavage, and then subjected to chemical derivatization to block reactive side chain groups, such as epsilon amino functions of lysine residues, with various protecting groups ("R"). The N-terminal peptide segment functions as a blocking group to protect the α-amino group ofthe N- terminal Gly of ECF2-aa from derivatization by the chemical protecting reagent. The amino protective groups, R, which are customary in polypeptide chemistry, e.g. those described in Houben-Weyl (Methoden der organischen Chemie 15/1 and 15/2, Thieme Verlag Stuttgart 1974), are suitable for use as protective groups. Prefened amino protective groups include benzyloxycarbonyl- ("Z"); tert-butyloxycarbonyl- ("BOC"); fluorenylmethoxycarbonyl- ("FMOC"); or adamantyloxycarbonyl- ("ADOC"). Other reactive side chain groups may also be protected by a protective group, e.g., hydroxyl and carboxy groups may be protected as benzyl ethers and benzyl esters respectively. YJL Preparation of a Protected ECF2-Ala Fragment A protected 10-32 fragment may be formed by first treating the minifusion protein with an appropriate derivatizing agent ("R agent") where R is the amino protective group (where n conesponds to the number of lysine residues in the minifusion protein). The resulting protected minifusion protein ("IVMFP" (SEQ ID NO:24)) may then be cleaved to form a protected 10-32 fragment ("R n -ECF2-Ala" (SEQ ID NO:23)) in which only the free ε-amino groups of Lys residues are protected by the "R" group and the α-amino group is not protected (see Scheme 3 below). The cleavage can be affected chemically or enzymatically. For the chemical cleavage, hydroxylamine may be used to cleave the Asn-Gly bond (indicated by the arrow), e.g., according to the procedure described by Bornstein, Biochemistry, 12, 2408-2421, (1979) to produce R n -ECF2-Ala (SEQ ID NO:23). The resulting R n -ECF2-Ala fragments (SEQ ID NO:23) can subsequently be purified by customary chemical methods if desired. In one example of this embodiment of the invention, a BOC-protected Val 241 -hCAH"-Linker-ECF2-Ala ("BOC 4 -MFP" (SEQ ID NO:24)) may be formed by reacting the MFP with BOC-anhydride. The resulting BOC 4 -MFP (SEQ ID NO:24) may be cleaved between the Asn and Gly amino acids residues with hydroxylamine to yield BOC 2 -ECF2-Ala (SEQ ID NO:23). SCHEME 3 MFP Val-Asp-Asn-Tφ-Arg-Pro-Ala-Gln- (SEQ ID NO:24) Pro-Leu-Lys(R)-Asn-Arg-Glu-Ile- + > Lys(R)-Ala-Phe-Val-Asp-Asp-Asp-Asp- "R agent" Asn-Gly-Lys(R)-Leu-Ser-Gln-Glu-Leu- His-Lys(R)-Leu-Gln-Thr-Tyr-Pro-Arg- Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala "R 4 -MFP" (SEQ ID NO:24) NH 2 OH Gly-Lys(R)-Leu-Ser-Gln-Glu-Leu- ► His-Lys(R)-Leu-Gln-Thr-Tyr-Pro-Arg- Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala "R 2 -ECF2-Ala" (SEQ ID NO:23) 12 Coupling of the Protected R g ECFZ-aa to ECFl Fragment to Produce Non- Amidated Elcatonin. The present invention additionally relates to the use of ECF2-aa (SEQ ID NO:22) or modified forms thereof, such as R n -ECF2-aa, in the preparation of calcitonin analogs such as Elcatonin (SEQ ID NO: 13). In this embodiment, the free α-amino group of R n -ECF2-aa (SEQ ID NO:22) may first be condensed using a non-enzymatic coupling reagent, in a manner customary to the person skilled in the art, onto the free carboxyl group of a peptide fragment such as ECFl (SEQ ID NO:7) or a protected ECFl to produce an Elcatonin presursor, such as Elcatonin-Ala. I (CH 2 ) 5 , C(O)-Ser-Asn-Leu-Ser-Thr-NHCHC(O)-Val-Leu-Gly-Lys-Leu-Ser-Gln-GIu-Leu- His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala "Elcatonin-Ala" (SEQ ID NO:31) For example, the condensation used to produce the Elcatonin precursor may be carried out with starting materials in which the hydroxyl group ofthe Ser and Thr residues and the side chain amino groups ofthe Lys residues are protected as described above. This results in the formation of a side chain protected, amino acid extended, non-amidated form of Elcatonin ("R n -Elcatonin-Ala (SEQ ID NO:31)). The condensation may be carried out, in a known manner, by the carbodiimide or by the azide method. After the two fragment have been chemically condensed, the product may be deprotected using conventional techniques appropriate for the particular protecting group, e.g., by hydrogenolysis, hydrolytically, by acids, by reduction, or by hydrazinolysis as described (Houben Weyl, Meth. der Org. Chemie, J >, 1-2 Thieme Verlag, Stuttgart, 1974). Conversion of Elcatonin-Ala to Elcatonin The conversion of an amino acid extended Elcatonin precursor to Elcatonin ofthe formula: I (CH 2 ) 5 -, C(O)-Ser-Asn-Leu-Ser-Thr-NHCHC(O)-Val-Leu-Gly-Lys-Leu-Ser-Gln-Glu-Leu- His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-NH 2 (SEQ ID NO: 13) may be affected, in accordance with WO 92/05271, by reacting a precursor polypeptide, Elcatonin-aa (SEQ ID NO:30) with a nucleophilic compound (e.g., ONPGA) in the 24 presence of a carboxypeptidase to give a cleavable intermediate, which may then be cleaved by photolysis to give Elcatonin (which exists as a C-teπτιinal α-carboxamide). The abbreviations used herein for the amino acids are: Gly, glycine; Lys, L-lysine; Leu, L-leucine; Ser, L-Serine; Gin, L-glutamine; Glu, L-glutamic acid; His, L-histidine; Thr, L-threonine; Tyr, L-tyrosine; Pro, L-proline; Arg, L-arginine; Asp, L-aspartic acid; Val, L-valine; Ala, L-alanine; Met, L-methionine; Asn, L-asparagine; Tφ, L-tryptophan; He, L-isoleucine; and Phe, L-phenylalanine. EXAMPLES 1.1 Preparation of the Plasmid pTBN26 Containing DNA Encoding the hCA-ECF2-Ala Fusion Protein A gene encoding amino acids 10-32 of ECF2 was constructed using PCR methodology. The following five oligonucleotides were synthesized at the University of Florida: 1.5'GGATCCAAGCTTGTTA3' (SEQIDNO:32) 2.5'GTCGACGAATTCGATA3' (SEQIDNO:33) 3.5'GGATCCAAGCTTGTTAACGGTAAACTGTCTCAGGAGCTC CATAAACTG3' (SEQIDNO:34) 4.5'CTGACGTTGGTGCTGGTACCCCGGCTTAAGATATCGAAT TCGTCGAC3" (SEQIDNO:35) 5.5'GGTACCAGCACCAACGTCAGTACGCGGGTAAGTCTGCAG TTTATGGAGCTCCTGAGA3' (SEQIDNO:36) Oligonucleotides 2-5 were combined in one PCR reaction mixture, PCR MIX 1. The 3' end of oligonucleotide 3 is complementary to the 3' end of oligonucleotide 5, while oligonucleotide 2 is complementary to the 3' end of oligonucleotide 4. These four nucleotides annealed together as shown in Figure 4A. During PCR, Taq DNA polymerase was used to extend oligonucleotide 3 to the 5' end of oligonucleotide 5, oligonucleotide 5 was extended to the 5' end of oligonucleotide 3, and oligonucleotide 2 was extended to the 5 ' end of oligonucleotide 4, as indicated by the dotted lines in diagram A. A second PCR reaction was used to join the PCR products from PCR MIX 1 resulting in a double stranded nucleotide fragment (SEQ ID NO:9) containing the complete, non-interrupted Asn-ECF2-Ala gene sequence as well as restriction sites to facilitate cloning. The PCR extended products derived from oligonucleotides 2 (2 xt (SEQ ID NO:8) and 3 E t respectively (SEQ ID NO:50)) have 20 bp of complementary sequence at their 3' ends (see schematic illustration in Figure 4B). During the first few cycles ofthe reaction with PCR MIX 2, oligonucleotides 2 Ext (SEQ ID NO:8) and 3 Ext (SEQ ID NO:50) annealed where their sequences were complementary and extended to create the double stranded fragment including the full length non-interrupted gene sequence for ECF2 (SEQ ID NO: 10). Finally, oligonucleotides 1 and 2 were used to amplify the full length gene sequence. Figures 11 and 12 show the nucleic acid sequences for the complete, non- interrupted ECF2 gene sequence (SEQ ID NO: 10) and for oligonucleotides 2 Ext (SEQ ID NO:8) and 3*' (SEQ ID NO:50) respectively. The amplified PCR product was digested with Hpa I and EcoR V. This blunt- ended DNA fragment, that codes for the C-terminal amino acid (Asn) ofthe polypeptide fragment Linker as well as the entire polypeptide fragment ECF2, was inserted into the pABN plasmid at the unique EcoR V site. The plasmids were screened to insure the Asn- ECF2 gene was inserted in the corcect orientation. The resultant plasmid was designated pABN26. Finally, pABN26 was digested with Xba I and BspE I and the entire Met- hC H' -Met 2 0 -Val 24 j -hC AII"-Linker-ECF2-aa sequence was transferred to pTBN plasmid that had been digested with the same enzymes to create production plasmid pTBN26 (Figure 5). The DNA sequence ofthe final construct with the Met cyanogen bromide cleavage site underlined and the Asn-Gly (SEQ ID NO:l 1) and conesponding amino acid sequence (SEQ ID NO: 12) cleavage site indicated by the arrow is shown in Figure 6. 1.2 Transformation ofthe Plasmid pTBN26 (Vector Containing the hCA- ECF2-aa DNA Fragments The transformation was carried out in accordance with the procedures described in WO 92/01707. The host microorganisms used were E. coli HB 101 and E. coli BL21(DE3), both being described in van Heeke et al., Protein Expression and Purification. 4, 265-275, (1993). 1.3 Selection ofthe Vectors Containing hCA~ECF2-Ala DNA The selection was carried out using standard procedures such as those described in WO 92/01707. The selection was based on the introduction of tetracycline resistance into the host organism. 2. Fermentation of E. coli Containing Plasmid pTBN26 2.1 Growth of a Preculture for Inoculating the Fermentor The E. coli strain BL21(DE3) containing plasmid pTBN26 was grown in Luria broth (LB) medium containing tetracycline (15 mg/L) and glucose solution (50 mg/L) in a shaking flask at 37 °C until an optical density at 550 nm (OD550) of about 4 had been reached, about 14 hours. The composition ofthe Luria broth medium (LB medium) is: 1.0 g/L Tryptone, 1.0 g/L NaCl and 0.5 g/L yeast extract. 2.2 Fermentation Fermentation was performed in a New Brunswick MPP-80 fermentor. The fermentation media, containing 300 g yeast extract, 30 g NaCl and 1200 g casamino acids dissolved in 15 L of H O, was added to the fermentor followed by 30 L of distilled water. The fermentor was sterilized in place at 121 °C for 25 minutes. After the contents ofthe fermentor had cooled to 37°C, the following sterile solutions were added sequentially: 480 g glucose in 800 mL H 2 0, 120 g MgSO 4 .H 2 O in 250 mL H 2 0, 495 g K 2 PO 4 and 465 g KH 2 PO in 3.0 L of H 2 O, and 0.9 g tetracycline hydrochloride in a mixture of 30 mL of 95% EtOH and 20 mL H 2 O. Also, a sterile mineral mix containing 3.6 g FeSO 4 « 7 H 2 O, 3.6 g CaCl 2 • 2 H 2 O, 0.90 g MnSO 4 , 0.90 g A1C1 3 • 6 H 2 O, 0.09 g CuCl 2 • 2 H 2 O, 0.18 g molybdic acid, and 0.36 g CoCl 2 » 6 H 2 O dissolved in 490.0 mL H 2 O and 10.0 mL concentrated HCl was added. Reagent grade NH 4 OH (28%) was attached to the automatic pH feed pump ofthe fermentor and the pH was adjusted to 6.8. The pH ofthe fermentation liquid was monitored continuously using a calibrated electrode and maintained at pH 6.8 by the intermittent addition of NH 4 OH. Additionally, dissolved oxygen was monitored continuously using a calibrated oxygen monitor. Oxygen concentration was maintained by adjusting the stirring rate. Aeration was maintained at 40 L/min. When all systems were operating normally, inoculation was performed by adding 600 mL of inoculum by sterile procedures. Turbidity, dissolved oxygen, and glucose levels were monitored throughout fermentation. When the turbidity reached an OD(550) of 15 to 20, the medium was supplemented with 300 g of yeast extract and 1,200 g of casamino acids. When the agitation rate reached 500 φm, pure oxygen was supplemented into the air feed at a rate of 5 L/min and the aeration rate was reduced to 20 L/min to maintain dissolved oxygen at 40%. When the turbidity reached 30 OD 550 units, the fermentation medium was rendered 2 mM with respect to isopropylthiolgalactoside to induce the expression ofthe plasmid. In addition, enough ZnCl 2 was added to render the final concentration 100 μM, and a sterile amino acid solution containing 225 g of L-Ser and 75 g each of L-Tyr, L-Tφ, L-Phe, L-Pro, and L-His was added to the medium. Two hours after induction, cell samples were removed for analysis. Dry weights and SDS-PAGE protein analysis were performed on samples taken at induction and every 30 minutes thereafter. At the end ofthe fermentation, the medium was transfened under sterile conditions to a sterile holding tank and cooled to 8°C. The spent medium was separated from the cells by crossflow filtration using a Millipore Pro Stack equipped with a 200kD molecular weight cut-off membrane. The cells were concentrated to 5 L, then either processed immediately or packaged in 1 L aliquots in plastic freezer bags and stored at - 20°C for later processing. Concentrated cells (5 L) were diluted in 32 L of lysis buffer (50 mM Tris, 1 M EDTA, 0.5% Triton-XlOO, pH 7.8, containing 0.05 mM phenylmethanesulfonyl fluoride) and then passed two times through a Gaulin APV pilot scale homogenizer operated at 12,000 psi at 4-15°C. The solution was then made 1.3 μM with respect to lysozyme, incubated for 15 minutes (4- 15°C) then passed through a homogenizer a second time. Approximately 50% ofthe soluble E.coli protein represents hCA-ECF2-aa, assessed by measuring the enzymatic activity ofthe human carbonic anhydrase portion of the fusion protein in accordance with Veφoorte et al., J. Biol. Chem. 242. 4221-4229, 1967. 2.3 Purification of he hCA-ECF2-Ala Fusion Protein The lysate (32 L) obtained from Example 2.2 was diluted 1 : 1 with the lysis buffer without added phenylmethanesulfonyl fluoride and polyethylenimine was added to a final concentration of 0.35%. The whole was stined for 20 min. and then centrifuged at 10,000 x g to remove precipitated DNA, RNA, nonessential proteins, and membrane vesicles and then filtered using a Pall Profile Filter (1.0 μm). The soluble fusion protein was subsequently purified by affinity chromatography. The pH ofthe filtered protein solution was adjusted to 8.7 by adding Tris base and loaded onto a 1 L column of p-aminomethylbenzenesulphonamide affinity resin (van Heeke et al., Methods. Molec. BioL 3_6_, 245-260, 1994) at a flow rate of 200 mL/min. After loading, the column was washed with 5 column volumes of 0.1 M Tris-sulphate buffer pH 9.0, containing 0.2 M K 2 SO 4 and 0.5 mM EDTA. The resin was then washed with 5 column volumes of 0.1 M Tris-sulphate buffer, pH 7.0, containing 1 M NaCl. The recombinantly produced hCA~ECF2-Ala fusion protein was eluted from the affinity material with 5 column volumes of 0.1 M Tris-sulphate buffer, pH 6.8, containing 0.4 mM potassium thiocyanate and 0.5 mM EDTA. Fractions containing the hCA~ECF2-Ala fusion protein were combined and treated with acetic acid to pH 4.0 to precipitate the product, which was subsequently collected by centrifugation. The resulting paste was frozen and lyophilized The yield for this step was 85%. 3. Cleavage of the hCA-ECF2-Ala Fusion Protein to Give ECF2-Ala 3.1 Cleavage to the hCA-ECF2-Ala Fusion Protein Using Hvdroxvlamine The fusion protein was cleaved with hydroxylamine between Asn and Gly into an hCAII-containing fragment and the polypeptide fragment ECF2-Ala (SEQ ID NO:23). Cleavage was achieved by incubating 40 g of hCA-ECF2-Ala dissolved in 1 L of hydroxylamine buffer (2 M hydroxylamine hydrochloride, 5 M guanidine hydrochloride, 50 mM 3 -(cyclohexylamino)-2 -hydroxy- 1 -propanesulphonic acid, adjusted to pH 10 with lithium hydroxide) for 4 h. An aliquot was removed every hour, and the extent to which the fusion protein has been cleaved to ECF2-Ala was determined by HPLC analysis (Cl 8 Vydac, 4.6 x 300 mm), buffer A: 0.1% trifluoroacetic acid, 5% acetonitrile by volume, 95% by volume water; buffer B: 0.1% trifluoroacetic acid, 5% by volume water; 95% by volume acetonitrile; linear gradient of 5% buffer A to 68% buffer B; flow rate: 1 mL/min). The reaction was then diluted to 4 L with 15% acetic acid whereupon the resultant precipitated hCAII-containing fragment was removed by centrifugation at 10000 x G. The resulting supernatant from the centrifugation containing ECF2-Ala (SEQ ID NO:23) was then desalted by loading onto a preparative C8 column (5x5.1 cm) equilibrated with 10 mM acetic acid in 5% acetonitrile at a flow rate of 50 mL/min. Following loading, the column was washed with 10 mM acetic acid in 10% acetonitrile, and the ECF2-Ala eluted with 10 mM acetic acid in 45% acetonitrile. The fractions containing ECF2-Ala, identified by analytical HPLC as above, were pooled and lyophilized. In all 1.14g of ECF2-Ala (SEQ ID NO:23) was obtained, conesponding to a yield of 82%. 3.2 Purification of ECF2-Ala For the further purification of ECF2-Ala (SEQ ID NO:23), a semipreparative polysulphoethylaspartamide HPLC was used as described in detail in Section 5.3 with a yield of 85%. 4. Conversion of ECF2-Ala to ECF2-Amide The amidation of ECF2-Ala (SEQ ID NO:23) was carried out according to procedures described in WO 92/05271. ECF2-Ala (12.8 mg) was dissolved in 1 mL of 5 mM EDTA, 25 mM moφholinoethane-sulfonic acid, pH 7.0, and to this was added 72 mg of o-nitrophenylglycine amide (ONPGA). The pH was adjusted to 6.0 with 5 M NaOH and carboxypeptidase- Y (120 μg) was added. After stirring in the dark for about 48 h, acetonitrile (1 mL) was added and the ECF2-ONPGA (SEQ ID NO:28) product purified by Cl 8 reverse phase HPLC as in section 5.2 and the product lyophilized. The course of the amidation reaction was followed by extracting samples for analysis after 10, 60, 120 and 180 min by analytical Cl 8 HPLC as in WO 92/05271. For the subsequent photolysis, the freezed-dried ECF2-ONPGA (12 mg) was dissolved in 5 mL 50% ethanol. To this solution was added NaHSO 3 (26 mg) and sodium benzoate (7.2 mg) and the pH adjusted to 9.5 with 5 M NaOH. Nitrogen was then passed through the reaction mixture for 15 min. The subsequent photolysis, analysis ofthe course ofthe reaction, and identification ofthe resulting ECF2-amide (SEQ ID NO:6), were carried out in accordance with the procedures described in WO 92/05271. 5. Cleavage of he hCA~ECF2-Ala Fusion Protein to Produce the Minifusion Protein .I Chemical Cleavage ofthe hCA~ECF2-Ala Fusion Protein Using Cyanogen Bromide When chemical rather than enzymatic fragment coupling was employed, the MFP (SEQ ID NO :24) was first cleaved from the fusion protein (SEQ ID NO : 12) . To cleave the Met 2 0 -Val 2 1 linkage (24 amino acids in the sequence prior to the beginning of ECF2-Ala), 40mg/mL ofthe hCA-ECF2-Ala fusion protein (SEQ ID NO: 12) was treated with 0.02 M cyanogen bromide in 70% formic acid at room temperature for 6 h under an argon atmosphere in the dark. Methionine (0.03 M) was then added to a final concentration of 0.03 M to terminate the cleavage reaction and the resulting solution was stined for 30 min. Twice the reaction volume of a solution containing 10% acetic acid and 112 g/L of sodium sulphate was added to the reaction mixture to precipitate the hCAIF-containing fragment and the mixture was stined for 20 min. The precipitated material was removed by centrifugation (10 min at 10,000 x G). The minifusion protein (SEQ ID NO:24) remained soluble in the supernatant. A 58% recovery of MFP (SEQ ID NO:24) in relation to hCA-ECF2-Ala fusion protein (SEQ ID NO: 12) employed, was obtained. 5.2 Desalting the Minifusion Protein The supernatant from the acid precipitation (4.5g of mini fusion protein) was loaded onto a C8 Vydac semi-preparative column (22 x 250 mm), which had been equilibrated in 0.1% trifluoracetic acid and 5% acetonitrile. The protein was eluted using 0.1% trifluoracetic acid in 25% acetonitrile, and subsequently lyophilized. In all, 4.05 g of 85% pure mini fusion protein was obtained, conesponding to a yield of 90%. 5.3 Purification ofthe Minifusion Protein Using Polvsulphoethvlaspartamide HPLC Polysulphoethylaspartamide chromatography was used for purification ofthe minifusion protein (SEQ ID NO:24), ECF2-Ala (SEQ ID NO:23) and ECF2-amide (SEQ ID NO:6). The peptide was taken up in buffer A (25 mM acetic acid, 35% acetonitrile) such that the final concentration was 5 mg/mL and then loaded onto a polysulphoethylaspartamide HPLC column (2.2 x 25 cm) at a flow rate of 20 mL/min. It was subsequently possible to elute the protein, over a period of 30 min, using a linear gradient of 10% buffer B (25 mM acetic acid, 400 mM sodium acetate, 35% acetonitrile) to 47% buffer B. Yields typically were 50% or greater. Figure 8 shows a representative HLPC trace of a sample containing ECF2-amide (SEQ ID NO:6). The peak for ECF2- amide appears between 14.5 and 16.3 min. 5.4 Desalting Following Polvsulphoethvlaspartamide HPLC Following lyophilization, the protein was loaded, for desalting, onto a C8 column (5 x 20 cm, equilibrated with 95% ethanol). The column was then washed with 4 column volumes of water and with 4 column volumes of 5% ethanol containing 1% acetic acid. The peptide was then eluted with 2 column volumes of 90% ethanol. The fractions were analyzed by HPLC. Yields typically were 80% or greater. 6, Incorporation of Protective Groups into the Minifusion Protein General Strategy: The α-amino group ofthe ECF2 fragment (SEQ ID NO:6) within the recombinant MFP (SEQ ID NO:24) is biologically protected, i.e. protected by the presence ofthe N- terminal hCAH" fragment. The ε-amino groups ofthe Lys groups in MFP were protected with acyl donors, such as Z, BOC, ADOC or FMOC. The reaction ofthe arginine- guanido function with Z-OSU was prevented by salt formation with HCl. The reaction of the His nitrogen with Z-OSU was suppressed by adding agents such as N- hydroxy succinimide . Experimental Procedure: MFP (SEQ ID NO:24) (270 mg) was dissolved in water (20 mL), and dioxane (4 mL) and 680 μL of 0.1 N HCl (to ensure salt formation at the two arginine-guanidino functions) was added. Prior to reaction, 78 mg of N-hydroxysuccinimide and 104.7 μL of triethylamine were added to protect the His nitrogen, and either 169 mg of Z-OSU, 146 mg of BOC-OSU, 135 mg of ADOC fluoride or 229 mg of FMOC-OSU were then added to the whole, with cooling. The reaction mixture was then stirred at room temperature for 24 h and subsequently dried in vacuo. The resulting residue was carefully triturated with dichloromethane (twice) and then with acetonitrile (twice). The product was collected by filtration and dried in vacuo. The yields ofthe Z protected mini fusion protein was 300 mg and of BOC-protected protein 295 mg, and that of ADOC -protected and FMOC- protected protein was 310 mg. Checking for complete reaction of mini fusion protein with the respective protective groups was carried out by means of thin layer chromatography using protected and unprotected peptides. Complete reaction was verified on thin layer silica plates (eluent: phenol :H2O, 775:225). The yield for the Z-OSU reaction when 540 mg of MFP (SEQ ID NO:24) was used was 75% and was typical of that found for the other blocking agents. 2, Cleavage of a Protected Mini Fusion Protein to Produce a Protected ECF2- Ala Fragment 7.1 Cleavage Using Hvdroxvlamine In order to liberate the α-amino group which was biologically protected by amino acid sequence, the protected mini fusion protein was cleaved with hydroxylamine between Asn and Gly into a Z-protected ECF2-Ala fragment (SEQ ID NO:23) and the 24 amino acid- long Tφ-containing fragment. The composition ofthe hydroxylamine buffer was the same as in Section 3.1. Hydroxylamine buffer (26 mL) was added to 260 mg of Z-protected minifusion protein (SEQ ID NO:24), and the whole was then ultrasonicated (20 sec) and the pH adjusted to pH 10.0 with 4 M lithium hydroxide. The resulting mixture was incubated at 30 °C and pH 10.0 for up to 5 h. The pH was then adjusted to 6.0 using concentrated acetic acid. An aliquot was removed every hour, and the extent to which the Z-protected minifusion protein (SEQ ID NO:24) has been cleaved to the Z-protected ECF2-Ala fragment (SEQ ID NO:23) was determined by HPLC analysis (C18 Vydac column, 5 x 300 mm), buffer A: 0.1% trifluoroacetic acid; buffer B 0.1% trifluoroacetic acid, 5% by volume H2O, 95% acetonitrile; eluent: linear gradient of 5% buffer A to 68% buffer B; 1 mL/min). Termination ofthe hydroxylamine cleavage was as in 3.1. Fractions obtained from the C8 column were analyzed by HPLC using a Vydac C 18 column. The buffers for the HPLC were those previously described. The flow rate was 1 mL/min. The proteins were eluted by a linear gradient from 41% buffer A to 71% buffer B. Detection was at 210 nm. In all, 156 mg of Z-protected ECF2-Ala ("Z-ECF2- Ala" (SEQ ID NO:23)) were obtained, corresponding to a yield of 60%. 7.2 Purification of Z-ECF2-Ala Z-ECF2-Ala (SEQ ID NO:23) was purified by use of a semi-preparative C8 HPLC. Z-ECF2-Ala (160 mg) was dissolved in 5 M acetic acid (5 mL), and buffer A (100 mM acetic acid, 5% acetonitrile (5 mL) was subsequently added. The sample was then loaded onto a semi-preparative HPLC C8 column (details as in 3.2.). Following the hydroxylamine cleavage and the purification, 120 mg of Z-ECF2-Ala (SEQ ID NO:23) was obtained, corresponding to a yield of 75% for the C8 purification step. For the further purification of Z-ECF2-Ala (SEQ ID NO:23), a semi-preparative polysulphoethylaspartamide HPLC was used as described in Section 5.3 below. Using this method, 59 mg of 95-98% pure Z-ECF2-Ala was obtained, conesponding to a yield of 85.5%. 8. Condensation of ECF2-amide and ECFl -OMe Amidated ECF2 (SEQ ID NO:6) produced according to Example 4 and the cyclic Elcatonin-fragment ECFl (SEQ ID NO:7) may be coupled in the presence of a non- enzymatic coupling reagent. For example, dicyclohexylcarbodiimide (DCC) and N- hydroxysuccinimide (HOSu) may be added to a solution of ECF 1 (SEQ ID NO:3) having the side hydroxyl groups of Ser and Thr protected as a benzyl ether and ECF2-amide (SEQ ID NO:2) having the reactive side chain groups of Lys, Ser, Thr and/or Glu residues protected. The reaction is stirred at about 0°C for 8 hours. Fragment condensation during this time was followed by HPLC analysis. After termination ofthe reaction, the mixture may be diluted by adding 1% trifluoracetic acid. The product Elcatonin (SEQ ID NO: 13) may be purified by preparative HPLC. Unreacted ECF2-amide (SEQ ID NO:2) may be isolated and purified by HPLC and recycled. 9. Chemical Coupling of Z-ECF2 to ECFl The coupling ofthe free α-amino group ofthe Z-ECF2-Ala fragment (i.e., EFC2- Ala having the side chain amino groups protected with a carbobenzyloxy group) to the free C-terminal α-carboxyl group ofthe peptide fragment ECFl may carried out either by the carbodiimide or the azide methods (see, e.g., Greenstein et al., in Chemistry ofthe Amino Acids. Vol. 2, John Wiley, New York, pp 804ff, 1016ff, (1961)). The coupling reaction is typically carried out by adding the Z-ECF2-Ala fragment to an activated ester formed from the C-terminal α-carboxylic acid ofthe ECFl fragment. Removal ofthe Cbz protecting groups from the coupling product may be carried out via hydrogenolysis and the resulting product purified by preparative HPLC to yield Elcatonin-Ala (i.e., "ECF1- ECF2-Ala"; SEQ ID NO:31). 10. Conversion of Elcatonin-Ala to Elcatonin- Amide The Elcatonin-Ala (SEQ ID NO:31) peptide produced according to Section 9 may be amidated using the procedure described in Section 4. The amidated Elcatonin (SEQ ID NO: 13) may be purified and subsequently desalted using the procedures described in Sections 5.3 and 5.4. The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope ofthe invention. The publications refened to in this specification are indicative ofthe level of ordinary skill in the art to which this invention pertains and are herein incoφorated by reference to the same extent as if each individual publication was specifically and individually indicated by reference. SEQUENCE LISTING (1) GENERAL INFORMATION (i) APPLICANT: (A) NAME: BioNebraska, Inc. (B) STREET: 3820 Northwest 46th Street <C) CITY: Lincoln (D) STATE: Nebraska (E) POSTAL CODE (ZIP) : 68524 (F) COUNTRY: United States of America (ii) TITLE OF THE INVENTION: RECOMBINANT PREPARATION OF CALCITONIN FRAGMENTS AND USE THEREOF IN THE PREPARATION OF CALCITONIN AND RELATED ANALOGS (iii) NUMBER OF SEQUENCES: 50 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Merchant & Gould (B) STREET: 3100 Norwest Center, 90 S. 7th Street (C) CITY: Minneapolis (D) STATE: Minnesota (E) COUNTRY: United States of America (F) ZIP: 55402 (v) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Diskette (B) COMPUTER: IBM Compatible (C) OPERATING SYSTEM: DOS (D) SOFTWARE: FastSEQ Version 1.5 (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: Unknown (B) FILING DATE: 04-FEB-1997 (C) CLASSIFICATION: (vii) PRIOR APPLICATION DATA: (A) APPLICATION NUMBER: 08/595,868 (B) FILING DATE: 06-FEB-1996 (viii) ATTORNEY/AGENT INFORMATION: (A) NAME: CARTER, Charles G. / BRUESS, Steven C. (B) REGISTRATION NUMBER: 35,093 / 34,130 (C) REFERENCE/DOCKET NUMBER: 8648.59WO01 (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: 612/371-5278 / 612/336-4711 (B) TELEFAX: 612/336-4751 (C) TELEX: (2) INFORMATION FOR SEQ ID NO:1 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 24 (D) OTHER INFORMATION: /note=alpha-carboxyl with -OH, -NH2, Amino Acid or Polypeptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1 : Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa 1 5 10 15 Xaa Xaa Gly Xaa Xaa Xaa Pro Xaa 20 (2) INFORMATION FOR SEQ ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 23 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa 1 5 10 15 Xaa Xaa Gly Xaa Xaa Xaa Pro 20 (2) INFORMATION FOR SEQ ID NO:3 : (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 1...6 (D) OTHER INFORMATION: note=L-aminosuberic acid linkage between positions 1 and 6 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: Xaa Xaa Leu Ser Thr Xaa Xaa Leu 1 5 (2) INFORMATION FOR SEQ ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 31 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 1...6 (D) OTHER INFORMATION: note=L-aminosuberic acid linkage between positions 1 and 6 (A) NAME/KEY: Other (B) LOCATION: 31...31 (D) OTHER INFORMATION: note=alpha-carboxyl with -OH, -NH2, Amino Acid or Polypeptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4: Xaa Xaa Leu Ser Thr Xaa Xaa Leu Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa 1 5 10 15 Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Gly Xaa Xaa Xaa Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 69 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear ( ii ) MOLECULE TYPE : Genomic DNA ( iii ) HYPOTHETICAL : NO ( iv) ANTISENSE : NO (v) FRAGMENT TYPE : (vi ) ORIGINAL SOURCE : ( ix) FEATURE : (A) NAME/KEY: Coding Sequence (B) LOCATION: 1...69 (D) OTHER INFORMATION: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: GGT AAA CTG TCT CAG GAG CTC CAT AAA CTG CAG ACT TAC CCG CGT ACT 48 Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg Thr 1 5 10 15 GAC GTT GGT GCT GGT ACC CCG 69 Asp Val Gly Ala Gly Thr Pro 20 (2) INFORMATION FOR SEQ ID NO:6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 23 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg 1 5 10 15 Thr Asp Val Gly Ala Gly Thr Pro 20 (2) INFORMATION FOR SEQ ID NO:7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 1...6 (D) OTHER INFORMATION: note=L-aminosuberic acid linkage between positions 1 and 6 (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7 : Ser Asn Leu Ser Thr Xaa Val Leu 1 5 (2) INFORMATION FOR SEQ ID NO: 8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 47 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: GACGACGAAT TCGATATCTT AAGCCGGGGT ACCAGCACCA ACGTCAG 47 (2) INFORMATION FOR SEQ ID NO:9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 111 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Coding Sequence (B) LOCATION: 16...90 (D) OTHER INFORMATION: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9: GGATCCAAGC TTGTT AAC GGT AAA CTG TCT CAG GAG CTC CAT AAA CTG CAG 51 Asn Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin 1 5 10 ACT TAC CCG CGT ACT GAC GTT GGT GCT GGT ACC CCG GCT TAAGATATCG AAT 103 Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro Ala 15 20 25 TCGTCGAC HI (2) INFORMATION FOR SEQ ID NO:10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 25 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10: Asn Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg 1 5 10 15 Thr Asp Val Gly Ala Gly Thr Pro Ala 20 25 (2) INFORMATION FOR SEQ ID NO:11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 864 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (i ) FEATURE: (A) NAME/KEY: Coding Sequence (B) LOCATION: 1...864 (D) OTHER INFORMATION: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11: ATG TCC CAT CAC TGG GGG TAC GGC AAA CAC AAC GGA CCT GAG CAC TGG 48 Met Ser His His Trp Gly Tyr Gly Lys His Asn Gly Pro Glu His Trp 1 5 10 15 CAT AAG GAC TTC CCC ATT GCC AAG GGA GAG CGC CAG TCC CCT GTT GAC 96 His Lys Asp Phe Pro lie Ala Lys Gly Glu Arg Gin Ser Pro Val Asp 20 25 30 ATC GAC ACT CAT ACA GCC AAG TAT GAC CCT TCC CTG AAG CCC CTG TCT 144 lie Asp Thr His Thr Ala Lys Tyr Asp Pro Ser Leu Lys Pro Leu Ser 35 40 45 GTT TCC TAT GAT CAA GCA ACT TCC CTG AGG ATC CTC AAC AAT GGT CAT 192 Val Ser Tyr Asp Gin Ala Thr Ser Leu Arg lie Leu Asn Asn Gly His 50 55 60 GCT TTC AAC GTG GAG TTT GAT GAC TCT CAG GAC AAA GCA GTG CTC AAG 240 Ala Phe Asn Val Glu Phe Asp Asp Ser Gin Asp Lys Ala Val Leu Lys 65 70 75 80 GGA GGA CCC CTG GAT GGC ACT TAC AGA TTG ATT CAG TTT CAC TTT CAC 288 Gly Gly Pro Leu Asp Gly Thr Tyr Arg Leu lie Gin Phe His Phe His 85 90 95 TGG GGT TCA CTT GAT GGA CAA GGT TCA GAG CAT ACT GTG GAT AAA AAG 336 Trp Gly Ser Leu Asp Gly Gin Gly Ser Glu His Thr Val Asp Lys Lys 100 105 110 AAA TAT GCT GCA GAA CTT CAC TTG GTT CAC TGG AAC ACC AAA TAT GGG 384 Lys Tyr Ala Ala Glu Leu His Leu Val His Trp Asn Thr Lys Tyr Gly 115 120 125 GAT TTT GGG AAA GCT GTG CAG CAA CCT GAT GGA CTG GCC GTT CTA GGT 432 Asp Phe Gly Lys Ala Val Gin Gin Pro Asp Gly Leu Ala Val Leu Gly 130 135 140 ATT TTT TTG AAG GTT GGC AGC GCT AAA CCG GGC CTT CAG AAA GTT GTT 480 lie Phe Leu Lys Val Gly Ser Ala Lys Pro Gly Leu Gin Lys Val Val 145 150 155 160 GAT GTG CTG GAT TCC ATT AAA ACA AAG GGC AAG AGT GCT GAC TTC ACT 528 Asp Val Leu Asp Ser lie Lys Thr Lys Gly Lys Ser Ala Asp Phe Thr 165 170 175 AAC TTC GAT CCT CGT GGC CTC CTT CCT GAA TCC TTG GAT TAC TGG ACC 576 Asn Phe Asp Pro Arg Gly Leu Leu Pro Glu Ser Leu Asp Tyr Trp Thr 180 185 190 TAC CCA GGC TCA CTG ACC ACC CCT CCT CTT CTG GAA TGT GTG ACC TGG 624 Tyr Pro Gly Ser Leu Thr Thr Pro Pro Leu Leu Glu Cys Val Thr Trp 195 200 205 ATT GTG CTC AAG GAA CCC ATC AGC GTC AGC AGC GAG CAG GTG TTG AAA 672 lie Val Leu Lys Glu Pro lie Ser Val Ser Ser Glu Gin Val Leu Lys 210 215 220 TTC CGT AAA CTT AAC TTC AAT GGG GAG GGT GAA CCC GAA GAA CTG ATG 720 Phe Arg Lys Leu Asn Phe Asn Gly Glu Gly Glu Pro Glu Glu Leu Met 225 230 235 240 GTG GAC AAC TGG CGC CCA GCT CAG CCA CTG AAG AAC AGG CAA ATC AAA 768 Val Asp Asn Trp Arg Pro Ala Gin Pro Leu Lys Asn Arg Gin lie Lys 245 250 255 GCT TTC GTT GAC GAC GAC GAC AAC GGT AAA CTG TCT CAG GAG CTC CAT 816 Ala Phe Val Asp Asp Asp Asp Asn Gly Lys Leu Ser Gin Glu Leu His 260 265 270 AAA CTG CAG ACT TAC CCG CGT ACT GAC GTT GGT GCT GGT ACC CCG GCT 864 Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro Ala 275 280 285 (2) INFORMATION FOR SEQ ID NO:12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 288 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12: Met Ser His His Trp Gly Tyr Gly Lys His Asn Gly Pro Glu His Trp 1 5 10 15 His Lys Asp Phe Pro lie Ala Lys Gly Glu Arg Gin Ser Pro Val Asp 20 25 30 lie Asp Thr His Thr Ala Lys Tyr Asp Pro Ser Leu Lys Pro Leu Ser 35 40 45 Val Ser Tyr Asp Gin Ala Thr Ser Leu Arg lie Leu Asn Asn Gly His 50 55 60 Ala Phe Asn Val Glu Phe Asp Asp Ser Gin Asp Lys Ala Val Leu Lys 65 70 75 80 Gly Gly Pro Leu Asp Gly Thr Tyr Arg Leu lie Gin Phe His Phe His 85 90 95 Trp Gly Ser Leu Asp Gly Gin Gly Ser Glu His Thr Val Asp Lys Lys 100 105 110 Lys Tyr Ala Ala Glu Leu His Leu Val His Trp Asn Thr Lys Tyr Gly 115 120 125 Asp Phe Gly Lys Ala Val Gin Gin Pro Asp Gly Leu Ala Val Leu Gly 130 135 140 He Phe Leu Lys Val Gly Ser Ala Lys Pro Gly Leu Gin Lys Val Val 145 150 155 160 Asp Val Leu Asp Ser He Lys Thr Lys Gly Lys Ser Ala Asp Phe Thr 165 170 175 Asn Phe Asp Pro Arg Gly Leu Leu Pro Glu Ser Leu Asp Tyr Trp Thr 180 185 190 Tyr Pro Gly Ser Leu Thr Thr Pro Pro Leu Leu Glu Cys Val Thr Trp 195 200 205 He Val Leu Lys Glu Pro He Ser Val Ser Ser Glu Gin Val Leu Lys 210 215 220 Phe Arg Lys Leu Asn Phe Asn Gly Glu Gly Glu Pro Glu Glu Leu Met 225 230 235 240 Val Asp Asn Trp Arg Pro Ala Gin Pro Leu Lys Asn Arg Gin He Lys 245 250 255 Ala Phe Val Asp Asp Asp Asp Asn Gly Lys Leu Ser Gin Glu Leu His 260 265 270 Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro Ala 275 280 285 (2) INFORMATION FOR SEQ ID NO:13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 31 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 1...6 (D) OTHER INFORMATION: note=L-aminosuberic acid linkage between positions 1 and 6. (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13: Ser Asn Leu Ser Thr Xaa Val Leu Gly Lys Leu Ser Gin Glu Leu His 1 5 10 15 Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 7 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14: Phe Val Asp Asp Asp Asp Asn 1 5 (2) INFORMATION FOR SEQ ID NO:15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Coding Sequence (B) LOCATION: 1...15 (D) OTHER INFORMATION: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15: GAC GAC GAC GAT AAA 15 Asp Asp Asp Asp Lys 1 5 (2) INFORMATION FOR SEQ ID NO:16: (I) SEQUENCE CHARACTERISTICS: (A) LENGTH: 5 amino acids (B) TYPE, amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (II) MOLECULE TYPE: protein (ill) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (Xl) SEQUENCE DESCRIPTION: SEQ ID NO:16: Asp Asp Asp Asp Lys 1 5 (2) INFORMATION FOR SEQ ID NO:17- (I) SEQUENCE CHARACTERISTICS- (A) LENGTH. 12 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (II) MOLECULE TYPE: Genomic DNA (ill) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Coding Sequence (B) LOCATION: 1...12 (D) OTHER INFORMATION. (x ) SEQUENCE DESCRIPTION: SEQ ID NO: 17: ATT GAA GGA AGA 12 He Glu Gly Arg 1 (2) INFORMATION FOR SEQ ID NO:18: (I) SEQUENCE CHARACTERISTICS: (A) LENGTH: 4 ammo acids (B) TYPE: amino acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (II) MOLECULE TYPE: protein (lli) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE, internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18: He Glu Gly Arg 1 (2) INFORMATION FOR SEQ ID NO:19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Coding Sequence (B) LOCATION: 1...24 (D) OTHER INFORMATION: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19: CAT CCT TTT CAT CTG CTG GTT TAT 24 His Pro Phe His Leu Leu Val Tyr 1 5 (2) INFORMATION FOR SEQ ID NO:20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20: His Pro Phe His Leu Leu Val Tyr 1 5 (2) INFORMATION FOR SEQ ID NO:21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 16 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21: Asp Asn Trp Arg Pro Ala Gin Pro Leu Lys Asn Arg Glu He Lys Ala 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:22: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO-.22: Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg Thr 1 5 10 15 Asp Val Gly Ala Gly Thr Pro Xaa 20 (2) INFORMATION FOR SEQ ID NO:23: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23: Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg Thr 1 5 10 15 Asp Val Gly Ala Gly Thr Pro Ala 20 (2) INFORMATION FOR SEQ ID NO:24: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 48 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24: Val Asp Asn Trp Arg Pro Ala Gin Pro Leu Lys Asn Arg Glu He Lys 1 5 10 15 Ala Phe Val Asp Asp Asp Asp Asn Gly Lys Leu Ser Gin Glu Leu His 20 25 30 Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro Ala 35 40 45 (2) INFORMATION FOR SEQ ID NO:25: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 17 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25: Val Asp Asn Trp Arg Pro Ala Gin Pro Leu Lys Asn Arg Glu He Lys 1 5 10 15 Ala (2) INFORMATION FOR SEQ ID NO:26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 27 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26: AGCTTTCGTT GACGACGACG ATATCTT 27 (2) INFORMATION FOR SEQ ID NO:27: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 27 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:27: AGCTAAGATA TCGTCGTCGT CAACGAA 27 (2) INFORMATION FOR SEQ ID NO:28: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 24...24 (D) OTHER INFORMATION: /note=o-N02-phenyglycine amide (xi) SEQUENCE DESCRIPTION: SEQ ID N0:28: Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg Thr 1 5 10 15 Asp Val Gly Ala Gly Thr Pro Xaa 20 (2) INFORMATION FOR SEQ ID NO:29: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 23 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: C-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29: Gly Lys Leu Ser Gin Glu Leu His Lys Leu Gin Thr Tyr Pro Arg Thr 1 5 10 15 Asn Thr Gly Ser Gly Thr Pro 20 (2) INFORMATION FOR SEQ ID NO:30: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 1...6 (D) OTHER INFORMATION: /note=L-aminosuberic acid linkage between positions l and 6 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30: Ser Asn Leu Ser Thr Xaa Val Leu Gly Lys Leu Ser Gin Glu Leu His 5 10 15 Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro Xaa 20 25 30 (2) INFORMATION FOR SEQ ID NO: 31: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (ix) FEATURE: (A) NAME/KEY: Other (B) LOCATION: 1...6 (D) OTHER INFORMATION: /note=L-aminosuberic acid linkage between positions 1 and 6 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:31: Ser Asn Leu Ser Thr Xaa Val Leu Gly Lys Leu Ser Gin Glu Leu His 1 5 10 15 Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro Ala 20 25 30 (2) INFORMATION FOR SEQ ID NO:32: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 16 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:32: GGATCCAAGC TTGTTA 16 (2) INFORMATION FOR SEQ ID NO:33: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 16 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID N0:33: GTCGACGAAT TCGATA 16 (2) INFORMATION FOR SEQ ID NO:34: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 48 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:34: GGATCCAAGC TTGTTAACGG TAAACTGTCT CAGGAGCTCC ATAAACTG 48 (2) INFORMATION FOR SEQ ID NO:35: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 47 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:35: CTGACGTTGG TGCTGGTACC CCGGCTTAAG ATATCGAATT CGTCGAC 47 (2) INFORMATION FOR SEQ ID NO:36: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 57 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:36: GGTACCAGCA CCAACGTCAG TACGCGGGTA AGTCTGCAGT TTATGGAGCT CCTGAGA 57 (2) INFORMATION FOR SEQ ID NO:37: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:37: Cys Ser Asn Leu Ser Thr Cys Val Leu Gly Lys Leu Ser Gin Glu Leu 1 5 10 15 His Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:38: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:38: Cys Ser Asn Leu Ser Thr Cys Val Leu Gly Lys Leu Ser Gin Glu Leu 1 5 10 15 His Lys Leu Gin Thr Tyr Pro Arg Thr Asn Thr Gly Ser Gly Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:39: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:39: Cys Ser Asn Leu Ser Thr Cys Val Leu Gly Lys Leu Ser Gin Asp Leu 1 5 10 15 His Lys Leu Gin Thr Phe Pro Arg Thr Asn Thr Gly Ala Gly Val Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:40: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:40: Cys Ser Asn Leu Ser Thr Cys Met Leu Gly Lys Leu Ser Gin Asp Leu 1 5 10 15 His Lys Leu Gin Thr Phe Pro Arg Thr Asn Thr Gly Ala Gly Val Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:41: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:41: Cys Ala Ser Leu Ser Thr Cys Val Leu Gly Lys Leu Ser Gin Glu Leu 1 5 10 15 His Lys Leu Gin Thr Tyr Pro Arg Thr Asp Val Gly Ala Gly Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:42: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS : single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:42: Cys Gly Asn Leu Ser Thr Cys Met Leu Gly Thr Tyr Thr Gin Asp Phe 1 5 10 15 Asn Lys Phe His Thr Phe Pro Gin Thr Ala He Gly Val Gly Ala Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:43: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:43: Cys Gly Asn Leu Ser Thr Cys Met Leu Gly Thr Tyr Thr Gin Asp Leu 1 5 10 15 Asn Lys Phe His Thr Phe Pro Gin Thr Asp He Gly Val Val Ala Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:44: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:44: Cys Ser Asn Leu Ser Thr Cys Val Leu Ser Ala Tyr Trp Arg Asn Leu 1 5 10 15 Asn Asn Phe His Arg Phe Ser Gly Met Gly Phe Gly Pro Glu Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:45: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:45: Cys Ser Asn Leu Ser Thr Cys Val Leu Ser Ala Tyr Trp Lys Asp Leu 1 5 10 15 Asn Asn Tyr His Arg Phe Ser Gly Met Gly Phe Gly Pro Glu Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO:46: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 32 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: N-terminal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:46: Cys Ser Asn Leu Ser Thr Cys Val Leu Ser Ala Tyr Trp Lys Asp Leu 1 5 10 15 Asn Asn Tyr His Arg Tyr Ser Gly Met Gly Phe Gly Pro Glu Thr Pro 20 25 30 (2) INFORMATION FOR SEQ ID NO-.47: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 28 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7: AGCTTTCGTT GACGACGACG ATATCTTA 28 (2) INFORMATION FOR SEQ ID NO:48: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 27 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:48: AAGCAACTGC TGCTGCTATA GAATCGA 27 (2) INFORMATION FOR SEQ ID NO:49: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: Internal (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:49: Lys Ala Phe Val Asp Asp Asp Asp He Leu 1 5 10 (2) INFORMATION FOR SEQ ID NO:50: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 84 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: Genomic DNA (iii) HYPOTHETICAL: NO (iv) ANTISENSE: NO (v) FRAGMENT TYPE: (vi) ORIGINAL SOURCE: (xi) SEQUENCE DESCRIPTION: SEQ ID NO:50: GGCTCCAAGC TTGTTAACGG TAAACTGTCT CAGGAGCTCC ATAAACTGCA GACTTACCCG 60 CGTACTGACG TTGGTGCTGG TACC 84

Claims: What is claimed is: 1. A recombinant method of synthesizing a calcitonin fragment comprising: (a) recombinantly forming a fusion protein which includes a target sequence linked to a carbonic anhydrase through a cleavage site; and (b) cleaving the fusion protein with a cleavage reagent to produce a first polypeptide including the target sequence, wherein the target sequence includes an amino acid sequence ofthe formula: A 1 o-A ι r A I2 -A 13 -A| 4 -A 15 -A 16 -A 17 -A 18 -A, 9 -A 20 -A 2 ,-A 22 -A 23 -A 24 -A 25 -A 26 - A 27 -Gly-A 29 -A 30 -A 31 -Pro-Xxx(SEQ ID NO:l) wherein A, 0 is Gly or Ser, A,, is Lys, Thr or Ala, A 12 is Leu or Tyr, A 13 is Ser, Thr or Tφ, A 14 is Gin, Lys or Arg, A ] 5 is Glu, Asp or Asn, A ]6 is Leu or Phe, A 17 is His or Asn, A 18 is Lys or Asn, A )9 is Leu, Tyr or Phe, A 20 is Gin or His, A 21 is Thr or Arg, A 22 is Tyr or Phe, A 23 is Pro or Ser, A 2 is Arg, Gly or Gin, A 25 is Thr or Met, A 26 is Asp, Ala, Gly, or Asn, A 27 is Val, Leu, He, Phe, or Thr, A 29 is Ala, Val, Pro or Ser, A 30 is Gly, Val or Glu, A 3] is Thr, Val or Ala, and -Xxx is -OH, -NH 2 , an amino acid residue or a polypeptide group. 2. The method of claim 1 wherein -Xxx is amino acid residue having an α-C(O)NH 2 group. 3. The method of claim 1 wherein A ]0 is Gly; the cleavage site includes Asn-A 10 ; and the cleaving step includes contacting the fusion protein with hydroxyl amine. 4. The method of claim 1 wherein -Xxx is -OH; and further comprising reacting the first polypeptide with an amidating agent to form a second peptide wherein -Xxx is -NH2. 5. The method of claim 1 wherein -Xxx includes an amino acid residue; further comprising converting the Pro-XXX sequence to a C-terminal Pro-NH 2 residue. 6. The method of claim 5 wherein the converting step comprises transamidating the - Xxx with an o-nitrobenzylamine to form a third peptide; and photolyzing the third peptide to form a second peptide including an amino acid sequence ofthe formula: Aio-A|j-A 12 -A,3-A M -A 1 5-A 16 -A 17 -A 18 -A,9-A 2 o-A 2 i-A2 2 -A 23 -A 2 4-A 25 -A 26 - A 27 -Gly-A 29 -A 30 -A 31 -Pro-NH 2 . (SEQ ID NO:2) 7. The method of claim 1 wherein the A 10 -A π -A, 2 -A 13 -A l4 -A 15 -A, 6 -A 17 -A 18 -A 19 - A 20 -A 2r A 22 -A 23 -A 24 -A 25 -A 26 -A 27 -Gly-A 29 -A 3 o-A 3 ,-Pro-Xxx (SEQ ID NO:l) sequence is: Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr- Asp-Val-Gly-Ala-Gly-Thr-Pro-Xxx. (SEQ ID NO:6) 8. The method of claim 1 further comprising reacting the fusion protein with a protecting reagent to form a protected fusion protein which includes an amino acid residue having a protected amino, hydroxyl or carboxy reactive side chain group. 9. The method of claim 8 comprising reacting the fusion protein with a protecting reagent to form a protected fusion protein which includes a Lys residue having a protected side chain amino group. 10. The method of claim 1 wherein the cleaving step includes contacting the fusion protein with the cleavage agent to form a minifusion protein including an amino acid sequence having the formula: Linker Peptide-A, 0 -A, 1 -A ]2 -A 13 -A 14 -A 15 -A 16 -A 17 -A 18 -A 19 -A 20 -A 2I -A 22 - A 23 -A 24 -A 25 -A 26 -A 27 -Gly-A 29 -A 30 -A 31 -Pro-X x. 11. The method of claim 10 wherein the minifusion protein has the formula: Val-Asp-Asn-Tφ-Arg-Pro-Ala-Gln-Pro-Leu-Lys-Asn-Arg-Glu-Ile-Lys- Ala-Phe-Val-Asp-Asp-Asp-Asp-Asn-Gly-Lys-Leu-Ser-Gln-Glu-Leu-His- Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asp-Val-Gly-Ala-Gly-Thr-Pro-Ala- Pro-Ala. (SEQ ID NO:24) 12. The method of claim 11 wherein the carbonic anhydrase is human carbonic anhydrase II and the cleavage agent includes cyanogen bromide. 13. The method of claim 11 further comprising cleaving the minifusion protein with hydroxylamine to form a peptide including an amino acid sequence ofthe formula: Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr- Asp-Val-Gly-Ala-Gly-Thr-Pro-Xxx. (SEQ ID NO:6) 14. The method of claim 10 further comprising reacting the mimfusion protein with a protecting reagent to form a protected minifusion protein including an amino acid residue having a protected amino, hydroxyl or carboxy reactive side chain group. 15. The method of claim 1 wherein the carbonic anhydrase is human carbonic anhydrase II; the target sequence includes an amino acid sequence ofthe formula: Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr- Asp-Val-Gly-Ala-Gly-Thr-Pro-Alac (SEQ ID NO:23), wherein -Alac is a C-terminal residue; and further comprising transpeptidating the -Alac with an o- nitrophenylglycinamide to form a third peptide; and photolyzing the third peptide to form a second peptide including an amino acid sequence ofthe formula: Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr- Asp-Val-Gly-Ala-Gly-Thr-Pro-NH 2 (SEQ ID NO:6). 16. The method of claim 15 wherein the cleavage site includes Asn-A 10 ; and the cleaving step includes contacting the fusion protein with hydroxylamine. 17. A nucleic acid sequence comprising a sequence ofthe formula: GGTAAACTGTCTCAGGAGCTCCATAAACTGCAGACTTAC CCGCGTACTGACGTTGGTACCCCG (SEQIDNO:5) 18. A method for producing a calcitonin carba analog comprising condensing an N- terminal fragment ofthe formula: wherein A 2 is Gly, Ser or Ala; A 3 is Asn or Ser; A 8 is Val or Met; R 2 is -(CH 2 ) 4 - or -CH(NH 2 )CH 2 S-S-; and Y is OH, OR 1 , where -R 1 is a lower alkyl group; with a recombinantly-formed polypeptide ofthe formula: A,o-A 1 ,-A 12 -Ai 3 -A, 4 -A 1 s-A 16 -A 17 -A, 8 -A 19 -A 2 o-A 21 -A 22 -A 23 -A 2 4-A 25 -A 26 - A 27 -Gly-A 29 -A 3 o-A 3r Pro-Xxx (SEQ ID NO:l) wherein a A 10 is Gly or Ser, A, j is wherein A 10 is Gly or Ser, A] ( is Lys, Thr or Ala, A 12 is Leu or Tyr, A 13 is Ser, Thr or Tφ, A 14 is Gin, Lys or Arg, A ]5 is Glu, Asp or Asn, A 16 is Leu or Phe, A, 7 is His or Asn, A 18 is Lys or Asn, A 19 is Leu, Tyr or Phe, A 20 is Gin or His, A 21 is Thr or Arg, A 22 is Tyr or Phe, A 23 is Pro or Ser, A 24 is Arg, Gly or Gin, A 25 is Thr or Met, A 26 is Asp, Ala, Gly, or Asn, A 27 is Val, Leu, He, Phe, or Thr, A 29 is Ala, Val, Pro or Ser, A 30 is Gly. Val or Glu, A 3 l is Thr, Val or Ala, and -Xxx is -OH, -NH 2 , an amino acid residue or a polypeptide group; in the presence of a non-enzymatic coupling reagent to form a calcitonin- derivative having the formula: A I3 -A I4 -A 15 -Aι 6 -A 17 -A 18 -A 19 -A 2 o-A 2 i-A 22 -A 23 -A 24 -A 25 -A 26 -A 27 -Gly-A 29 - A 30 -A 31 -Pro-Xxx. (SEQ ID NO:48) 19. The method of claim 18 wherein the non-enzymatic coupling reagent includes N- hydroxysuccinimide, N-hydroxybenzotriazole or a carbodiimide. 20. The method of claim 18 wherein the non-enzymatic coupling reagent includes (i) N-hydroxysuccinimide and dicyclohexylcarbodiimide; (ii) N-hydroxysuccinimide and N-ethyl-N'-dimethylaminopropylcarbodiimide; or (iii) N- hydroxybenzotriazole and dicyclohexylcarbodiimide. 21. A method for producing calcitonin or a related analog comprising condensing a desaminononapeptide ofthe formula: C(O)-A 2 -A 3 -Leu-Ser-Thr-NH-CH-C(O)-A 8 -Leu-Y CH 2 (CH 2 ) 3 CH 2 (SEQ ID NO:3) wherein A 2 is Gly, Ser or Ala; A 3 is Asn or Ser; A 8 is Val or Met; Y is OH, OR , where -R is a lower alkyl group; with a recombinantly-formed polypeptide ofthe formula: A, 0 -A ι r A 12 -A 13 -A 14 -A 15 -A 16 -A 17 -A 18 -A 19 -A 20 -A 21 -A 22 -A 23 -A 24 -A 25 -A 26 - A 27 -Gly-A 29 -A 30 -A 3 , -Pro-Xxx (SEQ ID NO: 1 ) wherein a A 10 is Gly or Ser, A n is wherein A )0 is Gly or Ser, A, , is Lys, Thr or Ala, A 1 is Leu or Tyr, A 13 is Ser, Thr or Tφ, A 14 is Gin, Lys or Arg, A 15 is Glu, Asp or Asn, A )6 is Leu or Phe, A 17 is His or Asn, A !8 is Lys or Asn, A 19 is Leu, Tyr or Phe, A 20 is Gin or His, A 2 | is Thr or Arg, A 22 is Tyr or Phe, A 23 is Pro or Ser, A 24 is Arg, Gly or Gin, A 25 is Thr or Met, A 26 is Asp, Ala, Gly, or Asn, A 27 is Val, Leu, He, Phe, or Thr, A 29 is Ala, Val, Pro or Ser, A 30 is Gly, Val or Glu, A 31 is Thr, Val or Ala, and -Xxx is -OH, -NH 2 , an amino acid residue or a polypeptide group; in the presence of a non-enzymatic coupling reagent to form a calcitonin- derivative having the formula: C(O)-A 2 -A 3 -Leu-Ser-Thr-NH-CH-C(O)-A g -Leu-A 10 -A π -A 12 - CH 2 (CH 2 ) 3 CH 2 A 1 3-A 14 -A i 5 -Aι 6 -A 17 -A 18 -A 1 9-A 20 -A 21 -A 22 -A 2 3-A 24 -A 2 5-A 26 -A2 7 -Gly-A2 9 - A 30 -A 3I -Pro-Xxx. (SEQ ID NO:4)

Inventors: FRANK JULIE A, HENRIKSEN DENNIS B, HOLMQUIST BART, PARTRIDGE BRUCE E, STOUT JAY S, WAGNER FRED W, FRANK, JULIE, A., HENRIKSEN, DENNIS, B., HOLMQUIST, BART, PARTRIDGE, BRUCE, E., STOUT, JAY, S., WAGNER, FRED, W.
Applicants: BIONEBRASKA INC, BIONEBRASKA, INC.
Application year: 1997
Main classification: C07K14
IPC codes: C07K14, C12N9, C12N15