Mitochondial enzymes regulated by reversible phosphorylation. Catalyzes the oxidative decarboxylation of the branched-chain a-keto acids derived from the essential amino acids, leucine, isoleucine and valine. Purified preparations undergo phosphorylation because endogenous kinase is tightly associated with the complex.
Specific Activity:
~8-10 mmol of NADH formed per min per mg of protein with a-ketoisovalerate as substrate.
Molecular Weight:
3200kD by sedimentation equilibrium centrifugation. Subunit apparent MW: 52kD (E2), 46kD (E1a), 35kD (E1b)
Storage and Stability:
Aliquot to avoid repeated freezing and thawing and store at -70 degrees C. Aliquots are stable for 6 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.