Transients in glycolytic metabolism following electrical activity in electrophorus

The cyclic increases and decreases of fluorescence emission of slices of the main organ of Electrophorus electricus which have been interpreted as DPN⁺ reduction at the glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) site are here correlated with assays of essential intermediates of glycolysis. Large increases of fructose 1,6-diphosphate, glyceraldehyde 3-phosphate, 3-phosphoglyceric acid and 2-phospholgyceric acid are found to occur at the time of the maximum increases of fluorescence and to have subsided as the flourescence increase subsides. Measurements of increased DPN concentration and glyceraldehyde 3-phosphate concentration identify the fluorescence increase with DPN⁺ reduction at glyceraldehyde-3-phosphate dehydrogenase. The activation of glycolysis appears to be due to a concentrated effect of increased ADP and creased ATP concentration upon phosphofructokinase (EC 2.7.1.11), 1,3-diphosphojlycerate kinase (EC 2.7.2.3) and glyceraldehyde-3-phosphate dehydrogenase. The possibility of other activators of phosphofructokinase is also to be considered.