Role of the phosphorylated imidazole group in phosphorylation and energy transfer reactions. In: Oxidative phosphorylation, 1963
Boyer, P.D.; Hultquist, D.E.; Peter, J.B.; Kreil, G.; Mitchell, R.A.; D.L.ca, M.; Hinkson, J.W.; Butler, L.G.; Moyer, R.W.
Federation Proceedings 22(4 Part 1): 1080-1087
Conditions governing the formation and disappearance of bound phosphohistidine in intact mitochondria and in a soluble enzyme system from bovine liver mitochondria are consistent with participation of the phosphorylated imidazole group as an intermediate in oxidative phosphorylation. The bound-phosphohistidine protein can be degraded by peptide-bond-splitting enzymes to yield free phosphohistidine, which is identical with 1 of the 2 synthetic isomers. Catalysis of the Pi[image] ATP and Pi[image] H2O exchange reactions by the soluble enzyme system give promise of unraveling the chemistry of the steps involved. The results suggest participation of an activated imidazole structure, possibly an acyl imidazole. This activated structure may react with Pi to give the phosphorylated imidazole or participate in energy-linked oxidation-reduction reactions at various steps in the electron transport chain. It would thus serve for energy transfers not involving adenine nucleotides. As a working hypothesis, all oxidative phosphorylation is considered to funnel through the formation of bound phosphohistidine.