, , | Name = Glucose-6-phosphate dehydrogenase | HGNCid = 4057 | Symbol = G6PD | AltSymbols =; G6PD1 | OMIM = 305900 | ECnumber = | Homologene = 37906 | MGIid = 105979 | GeneAtlas_image1 = PBB_GE_G6PD_202275_at_tn.png | Function = | Component = | Process = | Orthologs = }}Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme in the pentose phosphate pathway (see image), a metabolic pathway that supplies reducing energy to cells (most notably erythrocytes) by maintaining the level of the co-enzyme nicotinamide adenine dinucleotide phosphate (NADPH). The NADPH in turn maintains the level of glutathione in these cells that helps protect the red blood cells against oxidative damage. G6PD converts glucose-6-phosphate into 6-phosphoglucono-?-lactone and is the rate-limiting enzyme of the pentose phosphate pathway.450px|center|Mechanism of G6PD Glucose-6-phosphate dehydrogenase deficiency is very com