A flavoprotein enzyme that catalyzes the formation of acetolactate from 2 moles of PYRUVATE in the biosynthesis of VALINE and the formation of acetohydroxybutyrate from pyruvate and alpha-ketobutyrate in the biosynthesis of ISOLEUCINE. This enzyme was formerly listed as EC 4.1.3.18.

Synonyms: Synthase, Acetohydroxy Acid, Synthase, Acetolactate, Acid Synthase, Acetohydroxy, Acetohydroxy Acid Synthetase, Acetolactate Synthase, Synthase III, Acetoxyhydroxyacid, Acetohydroxy Acid Synthase, Acetohydroxyacid Synthetase I, Acetolactate pyruvate-lyase (carboxylating), Acetoxyhydroxyacid Synthase III, 0, Acetolactate Synthetase, Synthetase, Acetolactate, Synthetase, Acetohydroxy Acid, EC 2.2.1.6, Acid Synthetase, Acetohydroxy, Synthetase I, Acetohydroxyacid