Lipoic acid (α-lipoic, or thioctic, acid) - 6,8-dithioooctanoic acid.
CH 2 · CH 2 · CH (CH 2 ) 4 · COOH
S - S
Opened as an oxidation factor for α-keto acids in various microorganisms. Lipoic acid crystals are yellow plates, t ° pl 47.5 °, [α] 25 D = 96.7 °. Lipoic acid is stable in dry form, it polymerizes in solutions in the light, it is poorly soluble in water, and it is good in solutions of alkalis and organic solvents.
The biological role of lipoic acid is to participate in the oxidative decarboxylation of α-keto acids (pyruvic and α-ketoglutaric). In enzymatic reactions, lipoic acid is involved, which is bound to the protein through a peptide bond, which is formed between the lysine NH 2 group and the lipoic acid carboxyl group.
The introduction of lipoic acid into the body contributes to increased consumption of pyruvic and α-ketoglutaric acids, which accumulate in certain pathological conditions.