coproporphyrinogen

coproporphyrinogen

 [kop″ro-por″fĭ-rin´o-jen]
a porphyrinogen formed from uroporphyrinogen. Two isomers exist naturally, types I and III; the latter is a functional intermediate in heme biosynthesis while the former is produced in an abortive side reaction.

por·phy·rin·o·gens

(pōr'fi-rin'ō-jenz),
Intermediates in the biosynthesis of heme, as follows: four porphobilinogens condense to form uroporphyrinogens I and III (giving rise to side products uroporphyrins I and III) that are decarboxylated to form coproporphyrinogens I and III (giving rise to side products coproporphyrins I and III); coproporphyrinogen III is oxidized to protoporphyrinogen III (IX), which is then oxidized to form protoporphyrin III (IX) (this last intermediate adds ferrous iron to yield heme); certain porphyrinogens are elevated in certain porphyrias.

coproporphyrinogen

/cop·ro·por·phy·rin·o·gen/ (-por″fĭ-rin´o-jen) a porphyrinogen (q.v.) formed from uroporphyrinogen and existing naturally as two isomers, types I and III.

coproporphyrinogen

the fully reduced, colorless compound giving rise to coproporphyrin by oxidation.
References in periodicals archive ?
Pb inhibits the three enzymes responsible for heme synthesis; the heme: D-aminolevulinic acid dehydratase (ALAD), the coproporphyrinogen decarboxylase and the ferrochelatase [19].
We showed that this probably results from the competitive inhibition of hydroxymethylbilane synthase by coproporphyrinogen and protoporphyrinogen, substrates which accumulate in VP and HCP.
The association between a genetic polymorphism of coproporphyrinogen oxidase, dental mercury exposure and neurobehavioral response in humans.
The steps in the heme synthesis pathway that are most vulnerable to heavy metal inhibition are those that involve the enzymes uroporphyrin decarboxylase (UROD) and coproporphyrinogen oxidase (CPOX).
1991) showing that precoproporphyrin is formed as a consequence of Hg inhibition of uroporphyrinogen decarboxylase in the kidney during prolonged exposure, producing excess pentacarboxylporphyrinogen, which then competes with coproporphyrinogen as a substrate for coproporphyrinogen oxidase as the basis of precoproporphyrin formation (Woods et al.
Important biochemical features of VP include the increased biliary excretion of coproporphyrinogen and protoporphyrinogen and their corresponding porphyrins (4), which are commonly measured by fecal porphyrin analysis.
Lead is a potent inhibitor of [delta]-aminolevulinic acid dehydratase (ALAD), coproporphyrinogen oxidase, and ferrochelatase, enzymes that catalyze the second, sixth, and final steps, respectively, in the biosynthesis of heme (Onalaja and Claudio 2000; Warren et al.
Her uroporphyrinogen III synthase activity was not measured, and the coproporphyrinogen oxidase activity was increased threefold during a psychotic period, suggesting secondary porphyrinuria.
Pb depresses coproporphyrinogen oxidase, resulting in increased coproporphyrin activity.
Coproporphyrinogen oxidase, protoporphyrinogen oxidase, and ferrochelatase activities were assayed using lymphocytes, according to the methods reported previously (13-15).