Preparation of partially protected des-alanineB30-insulin-B-chain-disulphide and its use in semisynthesis.
The preparation of N alpha 1 N epsilon 29-bis-methylsulphonylethyloxycarbonyl-des-alanineB30-B-chain-disulphide-O gamma 13 O gamma 21-dimethyl ester is described. Starting with the di-S-sulphonate-B-chain it was prepared by i) removal of the C-terminal amino acid by digestion with carboxypeptidase A, ii) reduction and oxidation to form the cyclic disulphide, iii) esterification of the three carboxyl groups (alpha COOH = LysB29, gamma COOH - GluB13 and GluB21) followed by selective tryptic hydrolysis of the alpha-carboxyl ester, and iv) the protection of both amino groups (alpha NH2 = PheB1, epsilon NH2 = LysB29). This B-chain derivative was activated selectively at the C-terminal carboxyl group by formation of a mixed anhydride, and condensed with the dipeptide Thr-Arg. All protecting groups were removed by treatment with alkali. The human-B-chain C-terminal elongated with Arg was obtained in a yield of 30% based on the protected des-AlaB30-B-chain derivative.
D000818:Animals; D002417:Cattle; D007202:Indicators and Reagents; D007328:Insulin / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D010446:Peptide Fragments / Q000032:analysis; D014357:Trypsin
D007202:Indicators and Reagents; D007328:Insulin; D010446:Peptide Fragments; C036184:insulin, disulfide-des-Ala(B30)-; D014357:Trypsin