Studies on trypsin inhibitors. Part IV, Synthesis of the protected undecapeptide (sequence 25-35) of porcine pancreatic secretory trypsin inhibitor II (Kazal). |
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Authors: | A Guggi R Tomatis C A Benassi R Rocchi |
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Abstract: | Synthesis is described of the protected undecapeptide tert-butyloxycarbonylisoleucyl-threonyltyrosylserylasparaginyl-gamma-tert-butylglutamyl-S-acetamidomethylcysteinyl-valylleucyl-S-acetamidomethylcysteinylseriny hydrazide corresponding to positions 25-35 of the amino acid sequence of porcine pancreatic secretory trypsin inhibitor II (Kazal). The hepatapeptide free base methyl asparaginyl-gamma-tert-butylglutamyl-S-acetamidomethylcysteinylvalylleucyl-S-acetamidomethylcysteinylserinate (sequency 29-35) was acylated, by the azide procedure, with the tetrapeptide tert-butyloxycarbonl-isoleucylthreonyltyrosylserine hydrazide /sequence 25-28) and the resulting tert-butyloxycarbonylundecapeptide methyl ester was transformed into the corresponding hydrazide by hydrazinolysis. The stereochemical homogeneity of the final product was assessed, after partial deprotection with aqueous 90% trifuoroacetic acid, by digestion with papain and aminopeptidase M followed by quantitative amino acid analysis. |
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