Catalyzes the interconversion of 2-phosphoglycerate and 3-phosphoglycerate. (2R)-2-phosphoglycerate = (2R)-3-phosphoglycerate Optimum pH is 7.1. Optimum temperature is 60 degrees Celsius. Does not lose activity after 120 minutes at 60 degrees Celsius at pH7 with 50 uM of manganese chloride and 5 mM of magnesium chloride. Carbohydrate degradation; glycolysis; pyruvate from D-glyceraldehyde 3-phosphate: step 3/5. Monomer. Belongs to the BPG-independent phosphoglycerate mutase family. A-PGAM subfamily.