Amino acid sequence of penicillopepsin. II. Isolation and characterization of thermolytic peptides

The determination of the amino acid sequences of 70 peptides obtained from a thermolytic digest of penicillopepsin (EC 3.4.23.7) is described. Fifty-six unique sequences ranging from 2 to 13 amino acids were compiled. Among these was a heptapeptide whose sequence is nearly identical with that of the epoxide-reactive active site peptide of porcine pepsin (EC 3.4.23.1). Considering unrecognized overlaps, a minimum of 272 and a maximum of 293 unique amino acids have been obtained. They account for about 90% of the amino acids of the enzyme.