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 GPX3gene.[5][6][7]
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]
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]
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]
^Takahashi K, Avissar N, Whitin J, Cohen H (August 1987). "Purification and characterization of human plasma glutathione peroxidase: a selenoglycoprotein distinct from the known cellular enzyme". Archives of Biochemistry and Biophysics. 256 (2): 677–86. doi:10.1016/0003-9861(87)90624-2. PMID3619451.
^Chu FF (1994). "The human glutathione peroxidase genes GPX2, GPX3, and GPX4 map to chromosomes 14, 5, and 19, respectively". Cytogenetics and Cell Genetics. 66 (2): 96–8. doi:10.1159/000133675. PMID8287691.
^ abRazygraev AV, Petrosyan MA, Tumasova ZN, Taborskaya KI, Polyanskikh LS, Baziian EV, et al. (2019). "Changes in the Activity of Glutathione Peroxidase in the Blood Plasma and Serum of Rats during Postnatal Development and Aging". Advances in Gerontology. 9 (3): 283–288. doi:10.1134/s2079057019030147. S2CID202570586.
Lin JC, Kuo WR, Chiang FY, Hsiao PJ, Lee KW, Wu CW, et al. (May 2009). "Glutathione peroxidase 3 gene polymorphisms and risk of differentiated thyroid cancer". Surgery. 145 (5): 508–13. doi:10.1016/j.surg.2008.12.008. PMID19375609.
Holtzman JL (2002). "The role of low levels of the serum glutathione-dependent peroxidase and glutathione and high levels of serum homocysteine in the development of cardiovascular disease". Clinical Laboratory. 48 (3–4): 129–30. PMID11934214.
Iida R, Tsubota E, Yuasa I, Takeshita H, Yasuda T (April 2009). "Simultaneous genotyping of 11 non-synonymous SNPs in the 4 glutathione peroxidase genes using the multiplex single base extension method". Clinica Chimica Acta; International Journal of Clinical Chemistry. 402 (1–2): 79–82. doi:10.1016/j.cca.2008.12.027. PMID19161995.
Wang JY, Yang IP, Wu DC, Huang SW, Wu JY, Juo SH (October 2010). "Functional glutathione peroxidase 3 polymorphisms associated with increased risk of Taiwanese patients with gastric cancer". Clinica Chimica Acta; International Journal of Clinical Chemistry. 411 (19–20): 1432–6. doi:10.1016/j.cca.2010.05.026. PMID20576521.
Westphal K, Stangl V, Fähling M, Dreger H, Weller A, Baumann G, et al. (December 2009). "Human-specific induction of glutathione peroxidase-3 by proteasome inhibition in cardiovascular cells". Free Radical Biology & Medicine. 47 (11): 1652–60. doi:10.1016/j.freeradbiomed.2009.09.017. PMID19766714.
