The overall objective of the proposed research is to elucidate the mechanisms controlling the oxidation and synthesis of amino acids in skeletal muscle. Since skeletal muscle is the primary site in the body for the degradation of the branched chain amino acids, the degradative pathways for these amino acids will be investigated. The goals for the current year were to purify the ketoacid dehydrogenase which is the rate controlling step in the oxidation of the branched chain amino acids (leucine, isoleucine, valine) and determine how its activity is controlled.