Phosphoglycerate mutase () (PGAM) and bisphosphoglycerate mutase () (BPGM) are structurally related enzymes that catalyse reactions involving the transfer of phospho groups between the three carbon atoms of phosphoglycerate [, , ]. Both enzymes can catalyse three different reactions with different specificities, the isomerization of 2-phosphoglycerate (2-PGA) to 3-phosphoglycerate (3-PGA) with 2,3-diphosphoglycerate (2,3-DPG) as the primer of the reaction, the synthesis of 2,3-DPG from 1,3-DPG with 3-PGA as a primer and the degradation of 2,3-DPG to 3-PGA (phosphatase activity).In mammals, PGAM is a dimeric protein with two isoforms, the M (muscle) and B (brain) forms. In yeast, PGAM is a tetrameric protein.BPGM is a dimeric protein and is found mainly in erythrocytes where it plays a major role in regulating haemoglobin oxygen affinity as a consequence of controlling 2,3-DPG concentration. The catalytic mechanism of both PGAM and BPGM involves the formation of a phosphohistidine intermediate [].A number of other proteins including, the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase []that catalyses both the synthesis and the degradation of fructose-2,6-bisphosphate and bacterial alpha-ribazole-5'-phosphate phosphatase, which is involved in cobalamin biosynthesis, belong to this family [].This entry contains the active site phosphohistidine residue.
