Enzymatic formation of cholesteryl ester from cholesterol by gallbladder mucosa

The formation of cholesteryl ester from cholesterol and acyl CoA catalyzed by the enzyme acyl CoA:cholesterol acyltransferase (EC 2.3.1.26) was studied in guinea pig gallbladder mucosa homogenate and the subcellular fractions. The enzymatic activity was enriched in the microsomal fraction. Highest activity was observed with palmitoyl, stearoyl or oleoyl CoA as substrate. Lowest activity was observed with linoleoyl CoA. These data elucidate one mechanism for the formation of cholesteryl ester from cholesterol by the gallbladder wall.