Acylated Bovine Serum Albumin -- A New Substrate for Determining Cathepsin D Activity.

Abstract : Partially purified cathepsin D obtained from bovine uterus catalyzes the proteolysis of acylated bovine serum albumin (Ac-BSA). A sensitive method for measuring cathepsin D activity based on the use of Ac-BSA as the substrate is reported. In addition, the effect of pH and substrate concentration on the rate of proteolysis has been studied. The apparent Michaelis constant (Km) at pH 3.2 for the cathepsin D Ac-BSA complex was evaluated as 3.1 mg/ml.