MECHANISM OF ACTIVATION OF HOG PANCREATIC LIPASE BY SODIUM TAUROCHOLATE

A new preparation of hog pancreatic lipase is described which is evidently the most stable one of its kind. From the composition of the reaction mixtures after enzymatic hydrolysis with and without sodium taurocholate, it appears that the hydrolysis of triglyceride to diglyceride is facilitated and the hydrolysis of diglyceride to monoglyceride is depressed in the presence of taurocholate. The differences in the curves showing the rates of hydrolysis of triolein, monoolein, tributyrin, and monobutyrin in the presence and absence of taurocholate also indicate that the taurocholate acts to split the diglyceride–enzyme complex and thus increases the action of the enzyme on the triglyceride ester. The hydrolysis of the triglyceride is a fast reaction whereas the di- and mono-glycerides are hydrolyzed at much slower rates. The activation energy for the lipolysis of the triolein and tributyrin has been calculated in the presence and absence of taurocholate. This was possible because in spite of earlier reports that the lipolysis of triolein was not temperature dependent between 10 and 40 degrees, we found these reactions to be temperature dependent. The lesser activating effect at the highest taurocholate concentrations indicates this is not a simple emulsifying effect.