The Effect of Palmityl Coenzyme A on Pigeon Liver Fatty Acid Synthetase

Abstract

Abstract Because of the rather widespread interest in palmityl coenzyme A as a possible physiological inhibitor of a large number of enzymes, we have further investigated the inhibition of pigeon liver fatty acid synthetase by palmityl-CoA initially reported in 1958 by Porter and Long (1). The inhibition of the fatty acid synthetase is dependent on the presence of a critical mixed micellar concentration of palmityl-CoA and, more importantly, on the molar ratio of the CoA ester to protein. The molar ratio requirement eliminates the possibility of a site-specific inhibition of the fatty acid synthetase. It is concluded, rather, that palmityl-CoA inhibits this enzyme by virtue of its detergent nature. In support of this conclusion, data are reported which show that sodium lauryl sulfate, another strong detergent, acts in a similar way on the fatty acid synthetase. It is suggested, from the above results, that the inhibiting effect of palmityl-CoA on a number of enzymes reported in the literature may be solely or largely attributed to its detergent action. However, examination of these enzymes with respect to a possible molar ratio requirement for palmityl-CoA inhibition will be necessary before a final conclusion can be drawn.