Catalyzes the interconversion of 2-phosphoglycerate and 3-phosphoglyceratea crucial step in glycolysis, by using 2,3-bisphosphoglycerate. Also catalyzes the interconversion of (2R)-2,3-bisphosphoglycerate and (2R)-3-phospho-glyceroyl phosphate. (2R)-2-phosphoglycerate = (2R)-3-phosphoglycerate (2R)-3-phospho-glyceroyl phosphate = (2R)-2,3-bisphosphoglycerate + H(+) Homodimer. Acetylated at Lys-253, Lys-253 and Lys-254 under high glucose condition. Acetylation increases catalytic activity. Under glucose restriction SIRT1 levels dramatically increase and it deacetylates the enzyme (By similarity). Belongs to the phosphoglycerate mutase family. BPG-dependent PGAM subfamily.