Further characterization of a muscle factor which activates hepatic branched-chain ketoacid dehydrogenase

A skeletal muscle factor which activates hepatic branched-chain keto acid dehydrogenase has been described. Since this factor is labile, the present study was designed to stabilize and characterize this factor. The muscle factor was stabilized by the addition of KCl and the protease inhibitor, antipain. Muscle factor activity was localized to the 100,000 g pellet fraction of muscle homogenate. The muscle factor was inactivated following trypsin or phospholipase A2 digestion.