α;2‐Macroglobulin Inhibition of Endogenous Proteases in Fish Muscle

Abstract

ABSTRACTKinetic parameters for α;2‐macroglobulin inhibition of selected proteases (collagenase, cathepsin D, trypsin and chymotrypsin) were determined along with the extent of inhibition of the corresponding fish muscle proteases. Protease inhibition by α;2‐macroglobulin occurred in the presence of large macromolecular substrates but not in the presence of synthetic substrates. The inhibitor remained active at refrigerated temperatures (4–7°C). The α;2‐macroglobulin did not have any inhibitory effects on proteases in intact fish muscle tissue possibly due to lack of penetration of the tissues, but showed various levels of inhibition of proteases in tissue homogenates. Inhibitor concentration of 0.1% per weight of tissue homogenate resulted in about 17% loss of proteolytic activity while 0.4% inhibitor concentration caused complete loss of protease activity.