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Kielley 1951 J Biol Chem

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Publications in the MiPMap
Kielley WW, Kielley RK (1951) Myokinase and adenosinetriphosphatase in oxidative phosphorylation. J Biol Chem 191:485-500.

ยป PMID: 14861194 Open Access

Kielley WW, Kielley RK (1951) J Biol Chem

Abstract: A simplified procedure for preparing mitochondria suspensions from isotonic sucrose homogenates has been described. These preparations exhibit high rates of net 7 minute phosphorus formation from adenylic acid during the oxidation of ฮฑ-ketoglutarate in the absence of inhibitors such as fluoride, and show very low dephosphorylating activities.

It has been possible to study the complete phosphorylation of AMP in this system and to interpret the characteristics of this process on the basis of adenosinediphosphate as primary phosphate acceptor and the presence of a myokinase in mitochondria. The activity of this transphosphorylase has been directly determined and is of considerable magnitude. It has also been demonstrated that probably all of the myokinase is associated with the mitochondrial fraction.

The changes in the characteristics of oxidative phosphorylation and adenosinetriphosphatase activity as the result of incubation of the enzyme at 28ยฐ in the absence of substrates have been studied. The inactivation of the phosphorylation system by aging has been considered in two phases, an initial lag phase which is completely reversible in short aging experiments and a permanent reduction in activity observed with more severely aged mitochondria. The initial very low ATPase activity of the mitochondria was increased to appreciable magnitudes by aging. All the characteristics of aging were prevented to a large extent by AMP, ADP, or ATP. โ€ข Keywords: Myokinase, ATP, oxidative phosphorylation, AMP, ADP, phosphate acceptor


Labels: MiParea: Respiration 


Organism: Mouse  Tissue;cell: Liver  Preparation: Isolated mitochondria  Enzyme: Complex V;ATP synthase  Regulation: Coupling efficiency;uncoupling, Phosphate  Coupling state: OXPHOS 


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