A dimeric (a large and a small chain) or tetrameric (two large and two small chains) enzyme complex. Catalyzes the formation of acetolactate from pyruvate. [ http://www.ncbi.nlm.nih.gov/pubmed/8756689 GOC:jl http://www.ncbi.nlm.nih.gov/pubmed/16458324 ]
Synonyms: acetohydroxyacid synthase complex