Glycerol 3-phosphate dehydrogenase of boar spermatozoa: inhibition by alpha-bromohydrin phosphate

Boar spermatozoa incubated with glycerol 3-phosphate as substrate produced CO2 and an accumulation of dihydroxyacetone phosphate and fructose-1,6-bisphosphate. The rate of oxidation of glycerol 3-phosphate was decreased, as was the production of CO2 and the two glycolytic intermediates, in the presence of (R,S)-alpha-bromohydrin phosphate. In the presence of inhibitors of stage two of the glycolytic pathway, CO2 production was prevented, there was a marked increase in the concentration of the glycolytic intermediates but the rate of metabolism of the substrate was unaffected. Oxygen consumption by spermatoza incubated with glycerol 3-phosphate was unaffected in the presence of rotenone, whereas it was decreased when lactate was offered as the substrate. The results reported here confirm that in boar spermatozoa glycerol 3-phosphate dehydrogenase is an FAD-linked enzyme that is inhibited by (R,S)-alpha-bromohydrin phosphate in, possibly, a competitive manner.