Coenzyme-A-Dependent Esterification of Cholesterol in Intestinal Mucosa from Guinea-Pig. Influence of Diet on the Enzyme Activity

Abstract

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 K_m for the CoA in the combined enzyme reaction is 3.3 X 10⁻⁵M. 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.

Key-words:

• Acyl-CoA:cholesterol acyltransferase (ACAT)
• cholesterol
• cholesteryl ester
• Coenzyme A (CoA)
• guinea-pig
• intestine
• mucosal cell