Acid proteases from chicken liver.Cooperative hydrolysis of proteins

Abstract

Purified preparations of cathepsin D, BANA-hydrolase activity and dipeptidil aminopeptidase I from chicken liver, show a cooperative effect in the protein hydrolysis (acid-denatured haemoglobin and bovine serum albumin and native bovine serum albumin) at pH 5.0.The nature of the protein substrates determines their sensitivity to enzymatic digestion.The action of cathepsin D on proteins, in contrast which the BANA-hydrolase activity, releases polypeptides with high molecular weight, with scant–NH2 groups which can be valued by the ninhydrin method.These peptide fragments can then be further degraded by the protease BANA-hydrolase and the dipeptidil aminopeptidase I which is not active towards intact proteins.