Glucose-6-phosphate dehydrogenase

Glucose-6-phosphate dehydrogenase (G6PD or G6PDH) is a is_associated_with::cytosolic  is_associated_with::enzyme that catalyzes the is_associated_with::chemical reaction
 * D-glucose 6-phosphate + NADP+ $$\rightleftharpoons$$ 6-phospho-D-glucono-1,5-lactone + NADPH + H+

This enzyme is in the is_associated_with::pentose phosphate pathway (see image), a is_associated_with::metabolic pathway that supplies reducing energy to cells (such as is_associated_with::erythrocytes) by maintaining the level of the is_associated_with::co-enzyme nicotinamide adenine dinucleotide phosphate (NADPH). The NADPH in turn maintains the level of is_associated_with::glutathione in these cells that helps protect the red blood cells against oxidative damage. Of greater quantitative importance is the production of NADPH for tissues actively engaged in biosynthesis of fatty acids and/or isoprenoids, such as the liver, mammary glands, adipose tissue, and the adrenal glands. G6PD reduces nicotinamide adenine dinucleotide phosphate (NADP) to NADPH while oxidizing glucose-6-phosphate.

It is notable in humans when there is a genetic deficiency of G6PD which predisposes to non-immune mutation_results_in::hemolytic anemia.

Species distribution
G6PD is widely distributed in many species from is_associated_with::bacteria to is_associated_with::humans. In higher plants, several is_associated_with::isoforms of G6PDH have been reported, which are localized in the is_associated_with::cytosol, the is_associated_with::plastidic stroma, and is_associated_with::peroxisomes. Among humans, G6PD is common in certain insular groups, such as is_associated_with::Parsis.

Regulation
Glucose-6-phosphate dehydrogenase is stimulated by its substrate Glucose 6 Phosphate. The usual ratio of NADPH/NADP+ in the cytosol of tissues engaged in biosyntheses is about 100/1. Increased utilization of NADPH for fatty acid biosynthesis will dramatically increase the level of NADP+, thus stimulating G6PD to produce more NADPH.

G6PD converts is_associated_with::glucose-6-phosphate into is_associated_with::6-phosphoglucono-δ-lactone and is the rate-limiting enzyme of the pentose phosphate pathway.

G6PD is one of a number of glycolytic enzymes activated by the is_associated_with::transcription factor Hypoxia-inducible factor 1 (HIF1).

Clinical significance
G6PD is remarkable for its genetic diversity. Many variants of G6PD, mostly produced from is_associated_with::missense mutations, have been described with wide ranging levels of is_associated_with::enzyme activity and associated clinical symptoms. Two transcript variants encoding different is_associated_with::isoforms have been found for this gene.

is_associated_with::Glucose-6-phosphate dehydrogenase deficiency is very common worldwide, and causes acute is_associated_with::hemolytic anemia in the presence of simple infection, ingestion of is_associated_with::fava beans, or reaction with certain medicines, antibiotics, antipyretics, and antimalarials.



Cell growth and proliferation are affected by G6PD. G6PD inhibitors are under investigation to treat cancers and other conditions. is_associated_with::DHEA is a G6PD inhibitor.

List of medicines which cause lysis in G6PD
Note that this list doesn't contain all the medicines which cause is_associated_with::hemolysis:


 * is_associated_with::Antipyretics
 * is_associated_with::Acetamilide
 * is_associated_with::Acetophenetidin
 * is_associated_with::Antipyrine
 * is_associated_with::Aspirin
 * is_associated_with::Antimalarials
 * is_associated_with::Chloroquine
 * is_associated_with::Primaquine
 * is_associated_with::Pamaquine
 * is_associated_with::Quinocide
 * is_associated_with::Plasmoquine
 * is_associated_with::Sulfonamides
 * is_associated_with::Sulfamilamide
 * is_associated_with::SulfaCetamide
 * is_associated_with::Sulfapyridine
 * is_associated_with::Salicyayo sulfapyridine
 * is_associated_with::N2 acetyl sulfanilamide
 * is_associated_with::Nitrofurantoin
 * is_associated_with::Furaltadone
 * is_associated_with::Furazolidone
 * is_associated_with::Nitrofurazone
 * is_associated_with::Sulfuae
 * is_associated_with::Sulfoxone
 * is_associated_with::Thiazolsulfone
 * is_associated_with::Dapsone
 * is_associated_with::Dimercaprol
 * is_associated_with::Orianse
 * is_associated_with::Neo salvarsan
 * is_associated_with::Qulndene