Multifunctional enzyme that, as well as its role in glycolysis, plays a part in various processes such as growth control, hypoxia tolerance and allergic responses. (2R)-2-phosphoglycerate = H2O + phosphoenolpyruvate Binds two Mg(2+) per subunit. Required for catalysis and for stabilizing the dimer. Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 4/5. Dimer. Causes an allergic reaction in human. Binds to IgE. Belongs to the enolase family.