Solubilization of the 97-kDa native form of liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase

Anti-hyperlipidemic action of a newly synthesized benzoic acid derivative, S-2E

A newly synthesized benzoic acid derivative, (+)-(S)-p-[1-(p-tert-butylphenyl)-2-oxo-4-pyrrolidinyl]methoxybenzoic acid (S-2E), has the capacity to inhibit the biosynthesis of both sterol and fatty acids. Here, we report the mechanism by which S-2E lowers blood cholesterol and triglyceride levels. In the liver, S-2E was converted into its active metabolite, S-2E-CoA. S-2E-CoA noncompetitively inhibited the enzymatic activities of both 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase and acetyl-CoA carboxylase at K(i)=18.11 microM and K(i)=69.2 microM, respectively. Interestingly, pharmacokinetic experiments in rats showed that the concentration of S-2E-CoA in the liver was sufficient to inhibit the activities of HMG-CoA reductase and acetyl-CoA carboxylase, for example, when orally given to rats at 10 mg/kg. Indeed, S-2E (3-30 mg/kg) given orally suppressed the secretion rate of very-low-density lipoprotein (VLDL)-cholesterol and triglyceride in Triton WR-1339-injected rats. Furthermore, S-2E lowered the blood total cholesterol and triglyceride levels simultaneously in Zucker fatty rats. Collectively, S-2E may be useful in the treatment of familial hypercholesterolemia and mixed hyperlipidemia.