Glycolysis by an extract from pea seeds

Abstract

A partially purified extract from pea seeds, when supplemented with cofactor levels of adenosine triphosphate, diphosphopyridine nucleotide and Mg++ ions, catalyzed the conversion of starch, hexoses, glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate and fructose 1,6-diphosphate into carbon dioxide and ethanol. m[image]-Iodoacetate and fluoride inhibited glycolysis by the pea extract. Approximately 93% of glucose 1-phosphate and 85-90% of fructose and fructose 1,6-diphosphate were converted into carbon dioxide and ethanol. Within experimental error the ratio carbon dioxide: ethanol was 1. The following intermediary glycolytic transformations were demonstrated: hexoses and hexose monophosphates to fructose 1,6-diphosphate; fructose 1,6-diphosphate to triose phosphate and to 3-phosphoglyceric acid; 3-phosphoglyceric acid and pyruvate to carbon dioxide. Evidence was obtained for the operation of cycles involving the oxido-reduction of diphosphopyridine nucleotide and the inter-conversion of adenosine triphosphate and adenosine diphosphate. The ratio of adenosine triphosphate formed to carbon dioxide produced was calculated from the experimental data. A value of 1.73, compared with a theoretical figure of 2, was obtained. Reversibility of the glycolytic process was demonstrated in 2 stages. Pyruvate was converted into 3-phosphoglyceric acid and 3-phosphoglyceric acid into glucose. Evidence indicated that a complete Embden-Meyerhof-Parnas glycolytic system was functioning. Alternative pathways of hexose degradation were not operating to a significant extent.