Do mammalian cells synthesize lipoic acid? Identification of a mouse cDNA encoding a lipoic acid synthase located in mitochondria

Lipoic acid is a coenzyme essential to the activity of enzymes such as pyru vate dehydrogenase, which play important roles in central metabolism. Howev er, neither the enzymes responsible for biosynthesis nor the biosynthetic e vent of lipoic acid has been reported in mammalian cells. Ine this study, a mouse mLIP1 cDNA for Lipoic acid synthase has been identified. We have sho wn that the cDNA encodes a lipoic acid synthase by its ability to complemen t a mutant of Escherichia coli defective in lipoic acid synthase and that m LIP1 is targeted into the mitochondria. These findings suggest that mammali an cells are able to synthesize lipoic acid in mitochondria. (C) 2001 Feder ation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.