Cholesterol esterase (CE) is also known as cholesterol ester hydrolase. This enzyme catalyzes the following reaction: Sterol Ester --------> Sterol + Fatty Acid. Cholesterol esterase activity has been demonstrated in pancreas, intestine, liver and kidney. The enzyme is inactivated by proteolytic enzymes but stabilized by proteolytic enzyme inhibitors and by bile salts. CE from rat pancreas has a molecular weight of 65,000-69,000. In the presence of bile salts, it aggregates to a hexamer which is possibly the active form of the enzyme.