STUDY OF MECHANISM OF LIPOLYSIS INHIBITION BY BOVINE-MILK PROTEOSE-PEPTONE COMPONENT-3

Milk component 3 was an inhibitor of lipoprotein lipase activity respo nsible for spontaneous lipolysis occurring in milk stored at 4-degrees -C. Experiments using a pH-stat apparatus and emulsified tributyrin sh owed that component 3 inhibited porcine pancreatic lipase. The lipolyt ic activity was fully restored by addition of sodium taurodeoxycholate and colipase to the emulsion containing component 3. Inhibition did n ot seem to be the result of a direct interaction between component 3 a nd the enzyme. Component 3 had a strong adsorption power superior to t hat of pancreatic lipase, as shown by tensiometric measurements at an n-tetradecane-water interface. Lipase inhibition by component 3 could be the consequence of a rapid diffusion and preferential adsorption of component 3 at the oil-water interface provoking an important decreas e of interfacial tension and avoiding the adsorption of lipase.