Coproporphyrinogen III oxidase

Last updated
CPOX
2aex.jpg
Available structures
PDB Ortholog search: PDBe RCSB
Identifiers
Aliases CPOX , CPO, CPX, HCP, coproporphyrinogen oxidase, COX, HARPO
External IDs OMIM: 612732 MGI: 104841 HomoloGene: 76 GeneCards: CPOX
EC number 1.3.3.3
Orthologs
SpeciesHumanMouse
Entrez

1371

12892

Ensembl

n/a

ENSMUSG00000022742

UniProt

P36551

P36552

RefSeq (mRNA)

NM_000097

NM_007757

RefSeq (protein)

NP_000088

NP_031783

Location (UCSC)n/a Chr 16: 58.49 – 58.54 Mb
PubMed search [2] [3]
Wikidata
View/Edit Human View/Edit Mouse
Coprogen_oxidas
PDB 1vju EBI.jpg
coproporphyrinogen iii oxidase from leishmania major
Identifiers
SymbolCoprogen_oxidas
Pfam PF01218
InterPro IPR001260
PROSITE PDOC00783

Coproporphyrinogen-III oxidase, mitochondrial (abbreviated as CPOX) is an enzyme that in humans is encoded by the CPOX gene. [4] [5] [6] A genetic defect in the enzyme results in a reduced production of heme in animals. The medical condition associated with this enzyme defect is called hereditary coproporphyria. [7] [8]

Contents

CPOX, the sixth enzyme of the haem biosynthetic pathway, converts coproporphyrinogen III to protoporphyrinogen IX through two sequential steps of oxidative decarboxylation. [9] The activity of the CPOX enzyme, located in the mitochondrial membrane, is measured in lymphocytes. [10]

Function

CPOX is an enzyme involved in the sixth step of porphyrin metabolism it catalyses the oxidative decarboxylation of coproporphyrinogen III to proto-porphyrinogen IX in the haem and chlorophyll biosynthetic pathways. [5] [11] The protein is a homodimer containing two internally bound iron atoms per molecule of native protein. [12] The enzyme is active in the presence of molecular oxygen that acts as an electron acceptor. The enzyme is widely distributed having been found in a variety of eukaryotic and prokaryotic sources.

Structure

Gene

Human CPOX is a mitochondrial enzyme encoded by a 14 kb CPOX gene containing seven exons located on chromosome 3 at q11.2. [6]

Protein

CPOX is expressed as a 40 kDa precursor and contains an amino terminal mitochondrial targeting signal. [13] After proteolytic processing, the protein is present as a mature form of a homodimer with a molecular mass of 37 kDa. [14]

Clinical significance

Hereditary coproporphyria (HCP) and harderoporphyria are two phenotypically separate disorders that concern partial deficiency of CPOX. Neurovisceral symptomatology predominates in HCP. Additionally, it may be associated with abdominal pain and/or skin photosensitivity. Hyper-excretion of coproporphyrin III in urine and faeces has been recorded in biochemical tests. [15] HCP is an autosomal dominant inherited disorder, whereas harderoporphyria is a rare erythropoietic variant form of HCP and is inherited in an autosomal recessive fashion. Clinically, it is characterized by neonatal haemolytic anaemia. Sometimes, the presence of skin lesions with marked faecal excretion of harderoporphyrin is also described in harderoporphyric patients. [16]

To date, over 50 CPOX mutations causing HCP have been described. [17] Most of these mutations result in substitution of amino acid residues within the structural framework of CPOX. [18] At least 32 of these mutations are considered to be disease-causing mutations. [19] In terms of the molecular basis of HCP and harderoporphyria, mutations of CPOX in patients with harderoporphyria were demonstrated in the region of exon 6, where mutations in those with HCP were also identified. [20] As only patients with mutation in this region (K404E) would develop harderoporphyria, this mutation led to diminishment of the second step of the decarboxylation reaction during the conversion of coproporphyrinogen to protoporphyrinogen, implying that the active site of the enzyme involved in the second step of decarboxylation is located in exon 6. [17]

Interactions

CPOX has been shown to interact with the atypical keto-isocoproporphyrin (KICP) in human subjects with mercury (Hg) exposure. [21]

Related Research Articles

<span class="mw-page-title-main">Hereditary coproporphyria</span> Medical condition

Hereditary coproporphyria (HCP) is a disorder of heme biosynthesis, classified as an acute hepatic porphyria. HCP is caused by a deficiency of the enzyme coproporphyrinogen oxidase, coded for by the CPOX gene, and is inherited in an autosomal dominant fashion, although homozygous individuals have been identified. Unlike acute intermittent porphyria, individuals with HCP can present with cutaneous findings similar to those found in porphyria cutanea tarda in addition to the acute attacks of abdominal pain, vomiting and neurological dysfunction characteristic of acute porphyrias. Like other porphyrias, attacks of HCP can be induced by certain drugs, environmental stressors or diet changes. Biochemical and molecular testing can be used to narrow down the diagnosis of a porphyria and identify the specific genetic defect. Overall, porphyrias are rare diseases. The combined incidence for all forms of the disease has been estimated at 1:20,000. The exact incidence of HCP is difficult to determine, due to its reduced penetrance.

<span class="mw-page-title-main">Acute intermittent porphyria</span> Medical condition

Acute intermittent porphyria (AIP) is a rare metabolic disorder affecting the production of heme resulting from a deficiency of the porphobilinogen deaminase. It is the most common of the acute porphyrias.

<span class="mw-page-title-main">Protoporphyrinogen oxidase</span>

Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the PPOX gene.

<span class="mw-page-title-main">Porphobilinogen deaminase</span>

Porphobilinogen deaminase (hydroxymethylbilane synthase, or uroporphyrinogen I synthase) is an enzyme (EC 2.5.1.61) that in humans is encoded by the HMBS gene. Porphobilinogen deaminase is involved in the third step of the heme biosynthetic pathway. It catalyzes the head to tail condensation of four porphobilinogen molecules into the linear hydroxymethylbilane while releasing four ammonia molecules:

<span class="mw-page-title-main">Ferrochelatase</span>

Protoporphyrin ferrochelatase (EC 4.98.1.1, formerly EC 4.99.1.1, or ferrochelatase; systematic name protoheme ferro-lyase (protoporphyrin-forming)) is an enzyme encoded by the FECH gene in humans. Ferrochelatase catalyses the eighth and terminal step in the biosynthesis of heme, converting protoporphyrin IX into heme B. It catalyses the reaction:

<span class="mw-page-title-main">POLG</span> Protein-coding gene in the species Homo sapiens

DNA polymerase subunit gamma is an enzyme that in humans is encoded by the POLG gene. Mitochondrial DNA polymerase is heterotrimeric, consisting of a homodimer of accessory subunits plus a catalytic subunit. The protein encoded by this gene is the catalytic subunit of mitochondrial DNA polymerase. Defects in this gene are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions 1 (PEOA1), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), Alpers-Huttenlocher syndrome (AHS), and mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE).

<span class="mw-page-title-main">Cytochrome c oxidase subunit I</span> Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase I (COX1) also known as mitochondrially encoded cytochrome c oxidase I (MT-CO1) is a protein that in humans is encoded by the MT-CO1 gene. In other eukaryotes, the gene is called COX1, CO1, or COI. Cytochrome c oxidase I is the main subunit of the cytochrome c oxidase complex. Mutations in MT-CO1 have been associated with Leber's hereditary optic neuropathy (LHON), acquired idiopathic sideroblastic anemia, Complex IV deficiency, colorectal cancer, sensorineural deafness, and recurrent myoglobinuria.

<span class="mw-page-title-main">Cytochrome c oxidase subunit III</span> Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase subunit III (COX3) is an enzyme that in humans is encoded by the MT-CO3 gene. It is one of main transmembrane subunits of cytochrome c oxidase. It is also one of the three mitochondrial DNA (mtDNA) encoded subunits of respiratory complex IV. Variants of it have been associated with isolated myopathy, severe encephalomyopathy, Leber hereditary optic neuropathy, mitochondrial complex IV deficiency, and recurrent myoglobinuria.

<span class="mw-page-title-main">PMM2</span>

Phosphomannomutase 2 is an enzyme that in humans is encoded by the PMM2 gene.

<span class="mw-page-title-main">Proline oxidase</span>

Proline dehydrogenase, mitochondrial is an enzyme that in humans is encoded by the PRODH gene.

<span class="mw-page-title-main">SURF1</span> Protein-coding gene in the species Homo sapiens

Surfeit locus protein 1 (SURF1) is a protein that in humans is encoded by the SURF1 gene. The protein encoded by SURF1 is a component of the mitochondrial translation regulation assembly intermediate of cytochrome c oxidase complex, which is involved in the regulation of cytochrome c oxidase assembly. Defects in this gene are a cause of Leigh syndrome, a severe neurological disorder that is commonly associated with systemic cytochrome c oxidase deficiency, and Charcot-Marie-Tooth disease 4K (CMT4K).

<span class="mw-page-title-main">COX4I1</span> Protein-coding gene in the species Homo sapiens

Cytochrome c oxidase subunit 4 isoform 1, mitochondrial (COX4I1) is an enzyme that in humans is encoded by the COX4I1 gene. COX4I1 is a nuclear-encoded isoform of cytochrome c oxidase (COX) subunit 4. Cytochrome c oxidase is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Antibodies against COX4 can be used to identify the inner membrane of mitochondria in immunfluorescence studies. Mutations in COX4I1 have been associated with COX deficiency and Fanconi anemia.

<span class="mw-page-title-main">COX6B1</span> Protein-coding gene in the species Homo sapiens

Cytochrome c oxidase subunit 6B1 is an enzyme that in humans is encoded by the COX6B1 gene. Cytochrome c oxidase 6B1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. Mutations of the COX6B1 gene are associated with severe infantile encephalomyopathy and mitochondrial complex IV deficiency (MT-C4D).

<span class="mw-page-title-main">COX10</span> Mammalian protein found in Homo sapiens

Protoheme IX farnesyltransferase, mitochondrial is an enzyme that in humans is encoded by the COX10 gene. Cytochrome c oxidase (COX), the terminal component of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. This component is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may function in the regulation and assembly of the complex. This nuclear gene, COX10, encodes heme A: farnesyltransferase, which is not a structural subunit but required for the expression of functional COX and functions in the maturation of the heme A prosthetic group of COX. A gene mutation, which results in the substitution of a lysine for an asparagine (N204K), is identified to be responsible for cytochrome c oxidase deficiency. In addition, this gene is disrupted in patients with CMT1A duplication and with HNPP deletion.

<span class="mw-page-title-main">COX6A1</span>

Cytochrome c oxidase subunit 6A1, mitochondrial is a protein that in humans is encoded by the COX6A1 gene. Cytochrome c oxidase 6A1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. A mutation of the COX6A1 gene is associated with a recessive axonal or mixed form of Charcot-Marie-Tooth disease.

<span class="mw-page-title-main">FOXRED1</span>

FAD-dependent oxidoreductase domain-containing protein 1 (FOXRED1), also known as H17, or FP634 is an enzyme that in humans is encoded by the FOXRED1 gene. FOXRED1 is an oxidoreductase and complex I-specific molecular chaperone involved in the assembly and stabilization of NADH dehydrogenase (ubiquinone) also known as complex I, which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in FOXRED1 have been associated with Leigh syndrome and infantile-onset mitochondrial encephalopathy.

<span class="mw-page-title-main">COX7B</span> Protein-coding gene in the species Homo sapiens

Cytochrome c oxidase subunit 7B, mitochondrial (COX7B) is an enzyme that in humans is encoded by the COX7B gene. COX7B is a nuclear-encoded subunit of cytochrome c oxidase (COX). Cytochrome c oxidase is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Work with Oryzias latices has linked disruptions in COX7B with microphthalmia with linear skin lesions (MLS), microcephaly, and mitochondrial disease. Clinically, mutations in COX7B have been associated with linear skin defects with multiple congenital anomalies.

<span class="mw-page-title-main">FARS2</span>

Phenylalanyl-tRNA synthetase, mitochondrial (FARS2) is an enzyme that in humans is encoded by the FARS2 gene. This protein encoded by FARS2 localizes to the mitochondrion and plays a role in mitochondrial protein translation. Mutations in this gene have been associated with combined oxidative phosphorylation deficiency 14, also known as Alpers encephalopathy, as well as spastic paraplegia 77 and infantile-onset epilepsy and cytochrome c oxidase deficiency.

<span class="mw-page-title-main">Harderoporphyria</span> Medical condition

Harderoporphyria is a rare disorder of heme biosynthesis, inherited in an autosomal recessive manner caused by specific mutations in the CPOX gene. Mutations in CPOX usually cause hereditary coproporphyria, an acute hepatic porphyria, however the K404E mutation in a homozygous or compound heterozygous state with a null allele cause the more severe harderoporphyria. Harderoporphyria is the first known metabolic disorder where the disease phenotype depended on the type and location of the mutations in a gene associated with multiple disorders.

<span class="mw-page-title-main">COA7</span> Protein-coding gene in the species Homo sapiens

Cytochrome c oxidase assembly factor 7 (putative) (COA7), also known as Beta-lactamase hap-like protein, Respiratory chain assembly factor 1 (RESA1), Sel1 repeat-containing protein 1 (SELRC1), or C1orf163 is a protein that in humans is encoded by the COA7 gene. The protein encoded by COA7 is an assembly factor important for the mitochondrial respiratory chain. Mutations in COA7 have been associated with cytochrome c oxidase deficiency resulting in spinocerebellar ataxia with axonal neuropathy type 3 and mitochondrial myopathy.

References

  1. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000022742 - Ensembl, May 2017
  2. ↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  3. ↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ↑ Lamoril J, Martasek P, Deybach JC, Da Silva V, Grandchamp B, Nordmann Y (February 1995). "A molecular defect in coproporphyrinogen oxidase gene causing harderoporphyria, a variant form of hereditary coproporphyria". Human Molecular Genetics. 4 (2): 275–8. doi:10.1093/hmg/4.2.275. PMID   7757079.
  5. 1 2 Kohno H, Furukawa T, Yoshinaga T, Tokunaga R, Taketani S (October 1993). "Coproporphyrinogen oxidase. Purification, molecular cloning, and induction of mRNA during erythroid differentiation". The Journal of Biological Chemistry. 268 (28): 21359–63. doi: 10.1016/S0021-9258(19)36931-5 . PMID   8407975.
  6. 1 2 "Entrez Gene: CPOX coproporphyrinogen oxidase".
  7. ↑ "Hereditary coproporphyria". Genetic and Rare Diseases Information Center. National Institutes of Health. Retrieved 8 August 2011.
  8. ↑ "CPOX". Genetics Home Reference. Retrieved 8 August 2011.
  9. ↑ Sano S, Granick S (April 1961). "Mitochondrial coproporphyrinogen oxidase and protoporphyrin formation". The Journal of Biological Chemistry. 236 (4): 1173–80. doi: 10.1016/S0021-9258(18)64262-0 . PMID   13746277.
  10. ↑ Guo R, Lim CK, Peters TJ (October 1988). "Accurate and specific HPLC assay of coproporphyrinogen III oxidase activity in human peripheral leucocytes". Clinica Chimica Acta; International Journal of Clinical Chemistry. 177 (3): 245–52. doi:10.1016/0009-8981(88)90069-1. PMID   3233772.
  11. ↑ Madsen O, Sandal L, Sandal NN, Marcker KA (October 1993). "A soybean coproporphyrinogen oxidase gene is highly expressed in root nodules". Plant Molecular Biology. 23 (1): 35–43. doi:10.1007/BF00021417. PMID   8219054. S2CID   23011457.
  12. ↑ Camadro JM, Chambon H, Jolles J, Labbe P (May 1986). "Purification and properties of coproporphyrinogen oxidase from the yeast Saccharomyces cerevisiae". European Journal of Biochemistry. 156 (3): 579–87. doi: 10.1111/j.1432-1033.1986.tb09617.x . PMID   3516695.
  13. ↑ Martasek P, Camadro JM, Delfau-Larue MH, Dumas JB, Montagne JJ, de Verneuil H, Labbe P, Grandchamp B (April 1994). "Molecular cloning, sequencing, and functional expression of a cDNA encoding human coproporphyrinogen oxidase". Proceedings of the National Academy of Sciences of the United States of America. 91 (8): 3024–8. Bibcode:1994PNAS...91.3024M. doi: 10.1073/pnas.91.8.3024 . PMC   43507 . PMID   8159699.
  14. ↑ Martasek P, Nordmann Y, Grandchamp B (March 1994). "Homozygous hereditary coproporphyria caused by an arginine to tryptophane substitution in coproporphyrinogen oxidase and common intragenic polymorphisms". Human Molecular Genetics. 3 (3): 477–80. doi:10.1093/hmg/3.3.477. PMID   8012360.
  15. ↑ Taketani S, Kohno H, Furukawa T, Yoshinaga T, Tokunaga R (January 1994). "Molecular cloning, sequencing and expression of cDNA encoding human coproporphyrinogen oxidase". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1183 (3): 547–9. doi:10.1016/0005-2728(94)90083-3. PMID   8286403.
  16. ↑ Kim DH, Hino R, Adachi Y, Kobori A, Taketani S (December 2013). "The enzyme engineering of mutant homodimer and heterodimer of coproporphyinogen oxidase contributes to new insight into hereditary coproporphyria and harderoporphyria". Journal of Biochemistry. 154 (6): 551–9. doi:10.1093/jb/mvt086. PMID   24078084.
  17. 1 2 Hasanoglu A, Balwani M, Kasapkara CS, Ezgü FS, Okur I, Tümer L, Cakmak A, Nazarenko I, Yu C, Clavero S, Bishop DF, Desnick RJ (February 2011). "Harderoporphyria due to homozygosity for coproporphyrinogen oxidase missense mutation H327R". Journal of Inherited Metabolic Disease. 34 (1): 225–31. doi:10.1007/s10545-010-9237-9. PMC   3091031 . PMID   21103937.
  18. ↑ Lee DS, Flachsová E, Bodnárová M, Demeler B, Martásek P, Raman CS (October 2005). "Structural basis of hereditary coproporphyria". Proceedings of the National Academy of Sciences of the United States of America. 102 (40): 14232–7. Bibcode:2005PNAS..10214232L. doi: 10.1073/pnas.0506557102 . PMC   1224704 . PMID   16176984.
  19. ↑ Šimčíková D, Heneberg P (December 2019). "Refinement of evolutionary medicine predictions based on clinical evidence for the manifestations of Mendelian diseases". Scientific Reports. 9 (1): 18577. Bibcode:2019NatSR...918577S. doi:10.1038/s41598-019-54976-4. PMC   6901466 . PMID   31819097.
  20. ↑ Schmitt C, Gouya L, Malonova E, Lamoril J, Camadro JM, Flamme M, Rose C, Lyoumi S, Da Silva V, Boileau C, Grandchamp B, Beaumont C, Deybach JC, Puy H (October 2005). "Mutations in human CPO gene predict clinical expression of either hepatic hereditary coproporphyria or erythropoietic harderoporphyria". Human Molecular Genetics. 14 (20): 3089–98. doi: 10.1093/hmg/ddi342 . PMID   16159891.
  21. ↑ Heyer NJ, Bittner AC, Echeverria D, Woods JS (February 2006). "A cascade analysis of the interaction of mercury and coproporphyrinogen oxidase (CPOX) polymorphism on the heme biosynthetic pathway and porphyrin production". Toxicology Letters. 161 (2): 159–66. doi:10.1016/j.toxlet.2005.09.005. PMID   16214298.

Further reading

Heme synthesis--note that some reactions occur in the cytoplasm and some in the mitochondrion (yellow) Heme synthesis.png
Heme synthesis—note that some reactions occur in the cytoplasm and some in the mitochondrion (yellow)
This article incorporates text from the public domain Pfam and InterPro: IPR001260

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