Lipoic acid (LA), also known as α-lipoic acid and alpha lipoic acid (ALA) is an organosulfur compound derived from octanoic acid.
Inhibition of Glycine Conjugation
Lipoic acid was found to impair glycine conjugation of benzoic acid and decrease renal excretion of benzoylglycine in rats. Lipoic acid depleted hepatic CoA, carnitine, and glutathione, but not ATP. It increased the hepatic concentration of glycine.
In vitro using isolated and solubilized rat liver mitochondria, lipoic acid inhibited benzoyl-CoA synthetase (IC50 approximately 1.5 mM) and benzoyl-CoA:glycine N-acyltransferase (IC50 approximately 0.3 mM). Depletion of CoA and inhibition of the pertinent enzymes were assumed to be responsible for impairment of glycine conjugation of benzoic acid by lipoic acid.