Catalyzes the interconversion of 2-phosphoglycerate and 3-phosphoglycerate. (2R)-2-phosphoglycerate = (2R)-3-phosphoglycerate Inhibited to approximately 20% by EDTA. Optimum pH is 8.0. Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 3/5. Homotetramer. Belongs to the BPG-independent phosphoglycerate mutase family. A-PGAM subfamily.