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Gamma-glutamyl carboxylase

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(Redirected from GGCX)
GGCX
Identifiers
AliasesGGCX, VKCFD1, gamma-glutamyl carboxylase, Gamma-glutamyl carboxylase; GGCX
External IDsOMIM: 137167; MGI: 1927655; GeneCards: GGCX
Enzyme activity
EC #BRENDAExPASyKEGGMetaCyc
4.1.1.90↗↗↗↗
Orthologs
DatabasesNCBI: entry; OMA: entry
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000821
NM_001142269
NM_001311312

NM_019802

RefSeq (protein)

NP_000812
NP_001135741
NP_001298241

NP_062776

Location (UCSC)Chr 2: 85.54 – 85.56 Mbn/a
PubMed search[2][3]
Wikidata
View/Edit HumanView/Edit Mouse

Gamma-glutamyl carboxylase is an enzyme that in humans is encoded by the GGCX gene, located on chromosome 2 at 2p12.[4]

Function

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Gamma-glutamyl carboxylase is an enzyme that catalyzes the posttranslational modification of vitamin K-dependent proteins. Many of these vitamin K-dependent proteins are involved in coagulation so the function of the encoded enzyme is essential for hemostasis.[5] Most gla domain-containing proteins depend on this carboxylation reaction for posttranslational modification.[6] In humans, the gamma-glutamyl carboxylase enzyme is most highly expressed in the liver.

Catalytic reaction

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Gamma-glutamyl carboxylase oxidizes vitamin K hydroquinone to Vitamin K-2,3-epoxide, while simultaneously adding CO2 to protein-bound glutamic acid (abbreviation = Glu) to form gamma-carboxyglutamic acid (also called gamma-carboxyglutamate, abbreviation = Gla). Presence of two carboxylate groups causes chelation of Ca2+, resulting in change in tertiary structure of protein and its activation. The carboxylation reaction will only proceed if the carboxylase enzyme is able to oxidize vitamin K hydroquinone to vitamin K epoxide at the same time; the carboxylation and epoxidation reactions are said to be coupled reactions.[7][8]

a [protein]-α-L-glutamate (Glu) + phylloquinol (KH
2
) + CO
2
+ oxygen → a [protein] 4-carboxy-L-glutamate (Gla) + vitamin K 2,3-epoxide (KO) + H+
+ H
2
O

No experimental structure is known for GGCX, limiting understanding of its reaction mechanism. Based on the fact that the two reactions are coupled, a computational study is able to propose how the reactants interact with each other to form the products.[9] Lys228 has been shown to be the residue responsible for starting the reaction.[10] How the enzyme holds the reactants in place to have them interact with each other remains poorly shown. 491-507 and 395-401 are probably responsible for propeptide and glutamate binding respectively.[11]

Clinical significance

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Mutations in this gene are associated with vitamin K-dependent coagulation defect and PXE-like disorder with multiple coagulation factor deficiency.[5][12]

See also

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References

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  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000115486 – 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. ↑ Wu SM, Cheung WF, Frazier D, Stafford DW (December 1991). "Cloning and expression of the cDNA for human gamma-glutamyl carboxylase". Science. 254 (5038). New York, N.Y.: 1634–1636. Bibcode:1991Sci...254.1634W. doi:10.1126/science.1749935. PMID 1749935.
  5. 1 2 "Entrez Gene: GGCX".
  6. ↑ Brenner B, Tavori S, Zivelin A, Keller CB, Suttie JW, Tatarsky I, et al. (August 1990). "Hereditary deficiency of all vitamin K-dependent procoagulants and anticoagulants". British Journal of Haematology. 75 (4): 537–542. doi:10.1111/j.1365-2141.1990.tb07795.x. PMID 2145029. S2CID 24679257.
  7. ↑ Suttie JW (1985). "Vitamin K-dependent carboxylase". Annual Review of Biochemistry. 54 (1): 459–477. doi:10.1146/annurev.bi.54.070185.002331. PMID 3896125.
  8. ↑ Presnell SR, Stafford DW (2002). "The vitamin K-dependent carboxylase". Thrombosis and Haemostasis. 87 (6): 937–946. doi:10.1055/s-0037-1613115. PMID 12083499. S2CID 27634025.
  9. ↑ Silva PJ, Ramos MJ (2007). "Reaction mechanism of the vitamin K-dependent glutamate carboxylase: a computational study". The Journal of Physical Chemistry B. 111 (44): 12883–12887. doi:10.1021/jp0738208. PMID 17935315.
  10. ↑ Rishavy MA, Hallgren KW, Yakubenko AV, Shtofman RL, Runge KW, Berkner KL (November 2006). "Brønsted analysis reveals Lys218 as the carboxylase active site base that deprotonates vitamin K hydroquinone to initiate vitamin K-dependent protein carboxylation". Biochemistry. 45 (44): 13239–13248. doi:10.1021/bi0609523. PMID 17073445.
  11. ↑ Parker CH, Morgan CR, Rand KD, Engen JR, Jorgenson JW, Stafford DW (March 2014). "A conformational investigation of propeptide binding to the integral membrane protein γ-glutamyl carboxylase using nanodisc hydrogen exchange mass spectrometry". Biochemistry. 53 (9): 1511–1520. doi:10.1021/bi401536m. PMC 3970815. PMID 24512177.
  12. ↑ Vanakker OM, Martin L, Gheduzzi D, Leroy BP, Loeys BL, Guerci VI, et al. (March 2007). "Pseudoxanthoma elasticum-like phenotype with cutis laxa and multiple coagulation factor deficiency represents a separate genetic entity". The Journal of Investigative Dermatology. 127 (3): 581–587. doi:10.1038/sj.jid.5700610. hdl:11380/23189. PMID 17110937.

Further reading

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This article incorporates text from the United States National Library of Medicine, which is in the public domain.