Glycolysis in Haemonchus contortus larvae and rat liver

1. 1. The glycogen content of third-stage inefective Haemonchus contortus larvae was found to average 9·2 per cent on a dry weight basis 2. 2. The enzymes of the Embden-Meyerhof pathway of glycolysis were investigated in H. contortus and their activities compared with those of the corresponding enzymes in rat liver. 3. 3. Following enzymes were found to be present in H. contortus and possessed reaction rates very similar to the respective enzymes in rat liver; hexokinase, phosphoglucomutase, glucose-6-phosphate dehydrogenase, glucose-phsophate isomerase, mannosephosphate isomerase, phosphofructokinase, aldolase, triosephosphate isomerase, glyceraldehydephsophate dehydrogenase, phophoglycerate kinase, phosphoglyceromutse and phosphophyruvate hydratase. 4. 4. Under the assay conditions employed no pyruvate kinase could be detected in H. contortus. 5. 5. Lactate dehydrogenase requiring NAD as cofactor was present in H. contortus but its activity was extremely low compared to that of rat liver. 6. 6. Negligible glucose-6-phosphatase activity was detected in H. contortus in contrast with the considerable activity in rat liver. 7. 7. It appears that it is only in the steps involving the metabolism of phosphoenolpyruvate that glycolysis in the nematode differs markedly from that in vertebrate tissue.