This enzyme participates in both the breakdown and synthesis of glucose. alpha-D-glucose 1-phosphate = alpha-D-glucose 6-phosphate Binds 1 Mg(2+) ion per subunit. Mostly expressed in roots and coleoptiles, and, to a lower extent, in leaves, pollen and developing seeds. Expressed throughout embryo development, with a slight decrease during endosperm development, and fades out during aleurone development. Repressed in O(2) deprivated (hypoxia/anoxia) conditions. Autophosphorylated. Belongs to the phosphohexose mutase family.