Acetolactate synthase
（重定向自Acetohydroxy acid synthase）
![](/Images/godic/202412/14/Acetolactase_Synthase0220.png")
![](/Images/godic/202412/14/Acetolactate_synthase0220.png")
![](/Images/godic/202412/14/Aminosäuresynthese0220.png")
The acetolactate synthase (ALS) enzyme (also known as acetohydroxy acid synthase, or AHAS) is a protein found in plants and micro-organisms. ALS catalyzes the first step in the synthesis of the branched-chain amino acids (valine, leucine, and isoleucine).