Glutathione peroxidase 3

Glutathione peroxidase 3 (GPx-3), also known as plasma glutathione peroxidase (GPx-P) or extracellular glutathione peroxidase is an enzyme that in humans is encoded by the GPX3 gene.^[5][6][7]

GPX3
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2R37
Identifiers
Aliases	GPX3, GPx-P, GSHPx-3, GSHPx-P, glutathione peroxidase 3
External IDs	OMIM: 138321; MGI: 105102; HomoloGene: 20480; GeneCards: GPX3; OMA:GPX3 - orthologs
Gene location (Human) Chr. Chromosome 5 (human)[1] Band 5q33.1 Start 151,020,591 bp[1] End 151,028,988 bp[1]
Gene location (Mouse) Chr. Chromosome 11 (mouse)[2] Band 11|11 B1.3 Start 54,793,279 bp[2] End 54,801,203 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right lobe of thyroid gland right lung left lobe of thyroid gland gastric mucosa lower lobe of lung pericardium upper lobe of left lung human kidney cardiac muscle tissue of right atrium right auricle of heart Top expressed in right kidney gastrula human kidney decidua vestibular membrane of cochlear duct lactiferous gland stroma of bone marrow atrium ankle right lung More reference expression data BioGPS n/a
Gene ontology Molecular function oxidoreductase activity glutathione peroxidase activity selenium binding transcription factor binding protein binding peroxidase activity Cellular component extracellular region extracellular exosome extracellular space Biological process protein homotetramerization response to oxidative stress response to lipid hydroperoxide hydrogen peroxide catabolic process cellular oxidant detoxification cellular response to oxidative stress Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 2878 14778 Ensembl ENSG00000211445 ENSMUSG00000018339 UniProt P22352 P46412 RefSeq (mRNA) NM_002084 NM_001329790 NM_001083929 NM_008161 NM_001329860 RefSeq (protein) NP_001316719 NP_002075 NP_001316789 NP_032187 Location (UCSC) Chr 5: 151.02 – 151.03 Mb Chr 11: 54.79 – 54.8 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

GPx-3 belongs to the glutathione peroxidase family, which functions in the detoxification of hydrogen peroxide. It contains a selenocysteine (Sec) residue at its active site. The selenocysteine is encoded by the UGA codon, which normally signals translation termination. The 3' UTR of Sec-containing genes have a common stem-loop structure, the sec insertion sequence (SECIS), which is necessary for the recognition of UGA as a Sec codon rather than as a stop signal.^[5]

Thiol specificity

GPx-3 has a wide thiol specificity. The sources of reducing power for GPx-3 in vitro include GSH, cysteine, mercaptoethanol, and dithiothreitol.^[8] There is an evidence of effectiveness of homocysteine in reduction of GPx-3: GSH can be completely replaced by reduced homocysteine in vitro.^[9][10]

Changes during ontogeny

In the rat blood plasma, the GPx-3 activity is low during the first two weeks after birth and rapidly increasing during transition from milk nutrition to solid food. Aging is accompanied by decrease in GPx-3 activity: in the blood plasma of rats it occurs around 23-26 months of age.^[10]