Coenzyme-A-dependent esterification of cholesterol in intestinal mucosa from guinea-pig. Influence of diet on the enzyme activity.

Guinea-pig intestinal mucosa contains a microsomal enzyme which catalyses the esterification of cholesterol. The enzyme is CoA-dependent and probably an acyl-CoA-cholesterol acyltransferase (ACAT) (E.C. 2.3.1.26). The apparent Km for the CoA in the combined enzyme reaction is 3.3 x 10(-5)M. The specific activity of cholesterol esterification is about five times higher in young suckling animals than in ordinary fed adult animals. Feeding fat and fat/cholesterol diets increases the activity two- to five-fold. Concomitantly the fat/cholesterol fed animals get a marked accumulation of free and esterified cholesterol in mucosal cells.