- a water-soluble liquid, C3H4O3, important in many metabolic and fermentative processes, having an odor resembling that of acetic acid, prepared by the dehydration of tartaric acid: used chiefly in biochemical research.
- a colourless pleasant-smelling liquid formed as an intermediate in the metabolism of proteins and carbohydrates, helping to release energy to the body; 2-oxopropanoic acid. Formula: CH 3 COCOOH