Carbonyl groups associated with mitochondrial ATP synthesis

Abstract

In an attempt to define the chemical pathway responsible for ATP formation in mitochondria via oxidative phosphorylation, rat liver mitochondria were incubated with chemical compounds that are known to react with carbonyl groups. The effects of the compounds on P i-ATP exchange, ATPase and DNP-stimulated ATPase activity were determined. Hydroxylamine, semicarbazide, and cyanide were found to inhibit P i-ATP exchange activity and DNP-stimulated ATPase activity. Semicarbazide, labeled with carbon 14, was found to bind to mitochondria and the amount bound was dependent on the mitochondrial pretreatment procedure. Our results indicate that there is a functional carbonyl group(s) associated with mitochondrial ATP synthesis and with the reversal of electron transport by ATP.