Esterification of cholesterol in human small intestine: the importance of acyl-CoA:cholesterol acyltransferase.

Human intestinal mucosa contains acyl-CoA:cholesterol acyltransferase activity. The enzyme has been studied by using oleylcarnitine, CoA and carnitine palmitoyltransferase as an oleyl-CoA regenerating system. The enzyme was found in the particulate fraction of the cells, it had a pH optimum between 7.2 and 8.2, and was inhibited by taurocholate. The specific enzymic activity in biopsies from intestinal mucosa of normal men was found to be 3.6 +/- 1.37 nmol cholesteryl ester formed mg protein-1 h-1, an activity which can account for all cholesteryl esters in intestinal lymph. Low enzymic activity was found in biopsies from patients with small intestinal disorders. Two pancreatectomized patients had values within the normal range.