Ketopantoic acid is the organic compound with the formula HOCH<sub>2</sub>(CH<sub>3</sub>)<sub>2</sub>CC(O)CO<sub>2</sub>H. At physiological conditions, ketopantoic acid exists as its conjugate base, ketopantoate (HOCH<sub>2</sub>(CH<sub>3</sub>)<sub>2</sub>CC(O)CO<sub>2</sub><sup>âÂÂ</sup>).
Its biosynthesis proceeds from ketoisovalerate by hydroxymethylation:
This conversion is catalyzed by ketopantoate hydroxymethyltransferase, which gives ketopantoate.
Ketopantoate is substrate for 2-dehydropantoate 2-reductase, which produces (R)-pantoic acid, a precursor to pantothenic acid, a common prosthetic group.