ATP + pyruvate = ADP + H(+) + phosphoenolpyruvate Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 5/5. Homotetramer. In adults expressed predominantly in the thorax. Low levels in larvae and pupae, but increases in young adults, becoming relatively stable in two-day-old flies. Belongs to the pyruvate kinase family.