Factors which affect the activity of purified rat liver acyl-CoA oxidase

Abstract

The activity of the enzyme acyl-CoA oxidase (EC 1.3.99.3) is influenced by detergents. At concentrations above the critical micellar concentration, Triton X-100, Triton X-114 and Thesit stimulate oxidase activity. Lower concentrations of Triton X-100 and Triton X-114 render the acyl-CoA oxidase less sensitive towards substrate inhibition by palmitoyl-CoA or dec-4-cisenoyl-CoA. Other detergents inhibited the enzyme activity. CoA was found to be a relatively powerful competitive inhibitor of the enzyme, with a K(i,slope) value of 63 ± 3μM. This inhibition is dependent on an intact CoA molecule, as dephospho-CoA, dethio-CoA and acetyl-CoA are less potent inhibitors of the enzyme. Dec-2-trans-enoyl-CoA is a product-inhibitor of acyl-CoA oxidase, with a K(i,slope) value of 7 ± 1 μM.