1974 Volume 22 Issue 5 Pages 1087-1094
Five protected peptide subunits which cover the entire 58 amino acid residues of the bovine pancreatic basic trypsin inhibitor, i.e., Z-Arg (NO2)-Pro-Asp (OBzl)-Phe-Cys (Bzl)-Leu-Glu (OBzl)-Pro-Pro-Tyr-Thr-Gly-OH (I, positions 1-12), Z (OMe)-Pro-Cys (Bzl)-Lys (Z)-Ala-Arg (Tos)-Ile-Ile-Arg (Tos)-Tyr-Phe-Tyr-Asn-Ala-Lys (Z)-Ala-Gly-OH (II, positions 13-28), Z (OMe)-Leu-Cys (Bzl)-Gln-Thr-Phe-Val-Tyr-Gly-Gly-OH (III, positions 29-37), Z (OMe)-Cys (Bzl)-Arg (Tos)-Ala-Lys (Z)-Arg (Tos)-Asn-Asn-Phe-Lys (Z)-Ser-Ala-Glu (OBzl)-Cys (Bzl)-Met-Arg (Tos)-Thr-Cys (Bzl)-Gly-OH (IV, positions 38-56), Z (OMe)-Gly-Ala-OH (V, positions 57-58), were successively assembled on the polymer support by means of dicyclohexylcarbodiimide plus N-hydroxysuccinimide. In each step, the Z (OMe) group was deprotected by trifluoroacetic acid and the unreacted amino component on the resin was masked by acetylation. After deblocking of all protecting groups by HF and subsequent oxidation followed by affinity chromatographic purification, a highly active peptide, specific activity 82%, indistinguishable from the natural bovine pancreatic basic trypsin inhibitor, was isolated.