Studies on acyl-CoA synthetase in rat arterial wall

The properties and characteristics of acyl-CoA synthetase from the arterial wall of rats were investigated. The enzyme is located mainly in the microsomes. Its activity was found to be maximal at pH 7.0-8.0, and to be completely dependent on ATP, CoASH and Mg2+. The Km values for these substances were the same as those of the enzyme in liver. The activity was affected by serum, divalent cations, albumin, lipoproteins and phospholipids. In rats, the activity was decreased in various pathological conditions, such as tocopherol deficiency, hypertension and diabetes mellitus and was increased in hypercholesterolemia. The physiological significance of this enzyme in free fatty acid metabolism is discussed on the basis of these results.