Rapid purification of bovine kidney branched-chain 2-oxoacid dehydrogenase complex containing endogenous kinase activity.

Branched-chain 2-oxoacid dehydrogenase complex has been purified to near homogeneity by a simple, rapid procedure. The final product contains endogenous kinase activity capable of phosphorylating and inactivating the complex. Phosphorylation continues after complete inactivation, indicating the possibility of several phosphorylatable sites.