May be used by cells under conditions in which the level of glycolytic flux is very low. ATP + pyruvate = ADP + H(+) + phosphoenolpyruvate Not activated by fructose-1,6-bisphosphate. Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 5/5. Homotetramer. Present with 2130 molecules/cell in log phase SD medium. Belongs to the pyruvate kinase family.