EFFECT OF PANCREATIC COLIPASE ON THE LIPASE ACTIVITY OF MAMMALS AND MOLDS - COMPARATIVE-STUDY

In order to better characterize the specificity of pancreatic colipase interaction with lipase, we studied the effect of the coprotein on the lipase activity of mammals and of the molds Rhizopus arrhizus and Geotrichum candidum. Bile salts activity dependence curves against emulsified triolein showed that lipases from microorganisms were inhibited by bile salts in the same concentration range as pancreatic lipases. However, colipase did not restore enzymatic activity. Experiments carried out with Rhizopus lipase, acting on emulsified tributyrin in the presence of bile salts or non-ionic detergents, also demonstrated that pancreatic colipase failed to reactivate the enzyme. Kinetic studies of the hydrolysis of emulsified tributyrin, performed in the absence of detergent, showed that pancreatic and mold enzymes both inactivate upon denaturation at the tributyrin/water interface. When colipase was added to the system, pancreatic lipase was fully protected against surface denaturation. In contrast, colipase had no effect on the activity of mold lipases. From the results, it can be concluded that colipase specifically interacts with lipase synthesized by the same organ.