PPOX

Protoporphyrinogen oxidase is an is_associated_with::enzyme that in humans is encoded by the PPOX is_associated_with::gene.

PPOX (protoporphyrinogen oxidase) is a is_associated_with::human is_associated_with::gene that produces an is_associated_with::enzyme called is_associated_with::protoporphyrinogen oxidase. This enzyme is responsible for the seventh step in is_associated_with::heme production. Heme is the portion of hemoglobin that carries oxygen in the blood from the lungs to the rest of the body. Each of the steps in heme production is controlled by a separate gene (see below). Protoporphyrinogen oxidase removes is_associated_with::hydrogen atoms from is_associated_with::protoporphyrinogen IX (the product of the sixth step in the production of heme) to form is_associated_with::protoporphyrin IX. One additional enzyme must modify protoporphyrin IX before it becomes is_associated_with::heme.

The PPOX gene is located on the long (q) arm of chromosome 1 at position 22, from is_associated_with::base pair 157,949,266 to base pair 157,954,082.

The following genes are part of the chemical pathway for making heme.


 * is_associated_with::ALAD: aminolevulinate, delta-, dehydratase
 * is_associated_with::ALAS1: aminolevulinate, delta-, synthase 1
 * is_associated_with::ALAS2: aminolevulinate, delta-, synthase 2 (sideroblastic/hypochromic anemia)
 * CPOX: coproporphyrinogen oxidase
 * FECH: ferrochelatase (protoporphyria)
 * HMBS: hydroxymethylbilane synthase
 * PPOX: protoporphyrinogen oxidase
 * is_associated_with::UROD: uroporphyrinogen decarboxylase
 * is_associated_with::UROS: uroporphyrinogen III synthase (congenital erythropoietic porphyria)

Related conditions
is_associated_with::Variegate porphyria is caused by mutations in the PPOX gene. More than 100 mutations that can cause variegate porphyria have been identified in the PPOX gene. One mutation, a substitution of the is_associated_with::amino acid is_associated_with::tryptophan for is_associated_with::arginine at position 59 (also written as Arg59Trp or R59W), is found in about 95 percent of is_associated_with::South African families with variegate porphyria. Mutations in the PPOX gene reduce the activity of the enzyme made by the gene, allowing byproducts of heme production to build up in the body. This buildup, in combination with nongenetic factors (such as certain drugs, alcohol and dieting), causes this type of porphyria.