α-methylacetoacetic acid

α-meth·yl·ac·e·to·ace·tic ac·id (meth″əl-ə-se″to-ə-seґtik) acetoacetic acid methylated at the second carbon; attached to coenzyme A, it is an intermediate in isoleucine degradation. It is excreted in excess in the urine in α-methylacetoaceticaciduria.