Bovine pancreatic lipase. II. Stability and effect of activators and inhibitors

Purified bovine pancreatic lipase was highly unstable at and above refrigeration temperature. However, it could be stored frozen without loss of activity. Milk solids had some protective effect upon the enzyme against gamma-irradiation. Low concentrations of sodium, calcium, and magnesium salts stimulated lipolytic activity. However, heavy metal salts, such as ferric, cupric, and mercuric chlorides, were highly inhibitory. The bovine pancreatic lipase appeared to contain sulfhydryl groups which may be essential for the lipolytic activity since p-chloromercuribenzoate, N-ethylmaleimide, sodium arsenite, and iodoacetate inhibited the enzyme. A comparison of bovine pancreatic lipase and milk lipase revealed that the two enzymes were similar in thermal stability and effect of some of the activators and inhibitors on lipolytic activity.