(Integrates with Chapter 19.) On the basis of the following information, predict a reaction mechanism for the mammalian branchedchain -keto acid dehydrogenase complex (the BCKAD complex). This complex carries out the oxidative decarboxylation of the -keto acids derived from valine, leucine, and isoleucine. a. One form of maple syrup urine disease responds well to administration of thiamine. b. Lipoic acid is an essential coenzyme. c. The enzyme complex contains a flavoprotein.