Sterol Specificity of Pancreatic Cholesterol Esterase. ∗

Abstract

Summary

Pancreatic cholesterol esterase catalyzes the esterincation and hydrolysis of a number of different sterols and sterol esters. The order of activity observed in the esterifying system with oleic acid was as follows: dihydrocholesterol † cholesterol † β-sitosterol † sitosterol † stigmasterol † ergosterol. Of these sterols, only dihydrocholesterol and cholesterol were esterified with butyric acid. In the hydrolytic system all of the sterol butyrates tested were split very rapidly, with the exception of ergosterol butyrate. the order of splitting of the oleates in the first 4 hours was: cholesterol oleate † sitosterol oleate † stigmasterol oleate † ergosterol oleate. The relation of enzyme activity to sterol structure is discussed.