lipoic acid(redirected from protogen A)
Also found in: Dictionary, Encyclopedia.
li·po·ic ac·id(li-pō'ik as'id),
A bacterial growth factor present in yeast and liver extracts; may be useful in the treatment of mushroom poisoning. Functions as the amide (lipoamide) cofactor in the disulfide (-S-S-) form in the transfer of "active aldehyde" (acetyl), the two-carbon fragment resulting from decarboxylation of pyruvate from α-hydroxyethylthiamin pyrophosphate to acetyl-CoA, itself being reduced to the dithiol form (that is, dihydrolipoic acid) in the process. Lipoic acid is also an essential component of other α-keto acid dehydrogenase complexes.
An organic acid, C8H14S2O2, that is essential for decarboxylation of pyruvate to acetyl coenzyme A during aerobic metabolism. It is also used as a dietary supplement for its antioxidant properties.