Purification of branched chain alpha-ketoacid dehydrogenase complex from rat liver.

A new method using hydrophobic interaction chromatography on phenyl-Sepharose was developed to purify branched chain alpha-ketoacid dehydrogenase complex from commercially available frozen rat liver. Yields of greater than 50% were routinely achieved. The purified enzyme, composed of E1 alpha, E1 beta, and E2 subunits, appeared homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and contained endogenous kinase activity for phosphorylation and inactivation of the complex.