Oxidative phosphorylation coupled with the oxidation of alpha-ketoglutarate by heart-muscle sarcosomes.

Ochoa (1944) showed that inorganic phosphate was esterified when a-ketoglutarate was oxidized to succinate by particulate preparations obtained from heart muscle. These particles have been identified with the sarcosomes, the granules in muscle which correspond to mitochondria in other tissues (Cleland & Slater, 1953a, b; see also Harman & Feigelson, 1952). A recent paper (Slater, 1953b) described a procedure for measuring the yield of oxidative phosphorylation, in which adenosine diphosphate (ADP), glucose and yeast hexokinase were added to the reaction mixture, and the hexose monophosphate (HMP) formed was determined in the deproteinized mixture by a sensitive enzymic method (Slater, 1953a). The reactions occurring may be written as follows, in which ATP = adenosine triphosphate: