The aerobic inhibition of glycolysis in pea-seed extracts and its possible relationship to the Pasteur effect

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Abstract
Glycolysis by crude and partially-purified pea-seed extracts was inhibited by aerobic conditions. This effect of O2 was consistent with definitions of the Pasteur effect. The concentration of yeast-nucleotide fraction (added to the partially-purified pea-seed extract to replace cofactors) determined the extent of the aerobic inhibition of glycolysis. When adenosine tri-phosphate and diphosphopyridine nucleotide were added as cofactors, the degree of inhibition depended on the diphosphopyridine nucleotide concentration provided that this was between 10 and 100[mu]M. With higher concentrations of diphosphopyridine nucleotide no aerobic inhibition of glycolysis was observed. The aerobic inhibition of glycolysis was reversed by removing O2 or by adding cysteine, reduced glutathione or additional diphosphopyridine nucleotide. Increase of O2 partial pressure increased the inhibition of glycolysis. The glycolysis of fructose 1:6-diphosphate and its precursors was inhibited in air, but the breakdown of 3-phosphoglyceric acid to CO2 was unaffected. Addition of excess of mammalian glyceraldehyde 3-phosphate dehydro-genase prevented the aerobic inhibition of glycolysis. Endogenous glycer aldehyde 3-phosphate dehydrogenase was rapidly inhibited when the pea-seed extracts were incubated in air. In aerobic enzyme digest glycolytic activity was directly related to the protein SH-group concentration. It is concluded that the aerobic inhibition of glycolysis in pea-seed extracts was due to reversible inactivation of glyceraldehyde 3-phosphate dehydrogenase. The possible significance of the observations in relation to the Pasteur effect is discussed.