Isolation and sequential studies of peptides from tryptic digest of trichloroacetic acid precipitate of partly autolyzed alkaline protease from Aspergillus flavus

Abstract

A partly autolyzed preparation of the alkaline protease from As. flavus, denatured by trichloroacetic acid, was resolved into the high and low molecular weight part; the amino acid composition of both parts was similar to that of the native protease. The high molecular weight part was subjected to tryptic digestion; the digest was fractionated by chromatography on a sulfonated ion exchange resin and by paper electrophoresis and paper chromatography techniques. The peptides isolated were characterized by amino acid analysis and terminal end group analysis. Peptides obtained in larger quantities were sequenced. The data on peptides obtained in this study are compared with the results of earlier work on nonradioactive peptides from a partial hydrolysate of the [32P]DIP-labeled enzyme.