Collect. Czech. Chem. Commun. 1980, 45, 2131-2134

Isolation and characterization of a peptide derived from the active site of chicken pepsin

Helena Keilová, Vladimír Kostka and Miroslav Baudyš

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


A peptide was isolated from chicken pepsin which contains the aspartic acid residue reacting with diazoacetyl-D,L-norleucine methyl ester in the presence of Cu2+ -ions. The peptide is N-terminated with isoleucine and contains (besides isoleucine) valine, aspartic acid, two threonines, serine, and leucine. In concurrent experiments a peptide of the same composition was isolated from the thermolysin digest of chicken pepsin and its sequence determined as Ile-Val-Asp-Thr-Gly-Thr-Ser-Leu. Since both peptides have entirely identical amino acid composition and other characteristics, the sequenced peptide corresponds to the peptide isolated from the active site of the enzyme.