Evidence that a 41,000 dalton brain phosphoprotein is pyruvate dehydrogenase

Phosphorylation of a brain protein of M_r=41,000, termed band F₂, is selectively regulated by effectors of pyruvate dehydrogenase kinase (pyruvate, dichloroacetate, NAD, NADH, CoA, and acetyl CoA). Subcellular fractionation studies indicate a mitochondrial localization of a phosphoprotein with this molecular weight. The phosphorylated α-subunit of purified bovine kidney pyruvate dehydrogenase comigrates with band F₂ on polyacrylamide gels and both appear as a doublet band of M_r=41,000−42,000. On the basis of similar regulatory properties, subcellular location and electrophoretic mobility, we propose that band F₂ is the α-subunit of the brain pyruvate dehydrogenase complex. Because band F₂ can be affected by physiological and behavioral treatments, our hypothesis suggests a potential regulatory role for pyruvate dehydrogenase in brain function.