该基因编码的蛋白属于谷胱甘肽过氧化物酶家族，其成员通过谷胱甘肽催化有机过氧化氢和过氧化氢（H2O2）的还原，从而保护细胞免受氧化损伤。其他研究表明，H2O2对于生长因子介导的信号转导、线粒体功能和巯基氧化还原平衡的维持也是必不可少的，因此，通过限制H2O2积累，谷胱甘肽过氧化物酶也参与调节这些过程。在脊椎动物中存在多种基因家族的同工酶，它们在细胞位置和底物特异性方面有所不同。这种同工酶是最丰富的，是无处不在表达和定位在细胞质中，其首选底物是过氧化氢。它也是一种硒蛋白，其活性部位含有稀有氨基酸硒代半胱氨酸（SEC）。sec由uga密码子编码，通常表示翻译终止。硒蛋白mRNAs的3’UTRs包含一个保守的茎环结构，被指定为Sec插入序列（Sec is）元素，这是将UGA识别为Sec密码子而不是停止信号所必需的该基因在编码区含有一个框架内GCG三核苷酸重复序列，在人类群体中发现了3个重复序列为4、5或6的等位基因具有4个gcg重复序列的等位基因与绝经前妇女乳腺癌风险显著相关。另外，已经发现该基因的剪接转录变体。在X染色体和21染色体上已鉴定出该位点的假基因[由RefSeq提供，2017年8月]
The protein encoded by this gene belongs to the glutathione peroxidase family, members of which catalyze the reduction of organic hydroperoxides and hydrogen peroxide (H2O2) by glutathione, and thereby protect cells against oxidative damage. Other studies indicate that H2O2 is also essential for growth-factor mediated signal transduction, mitochondrial function, and maintenance of thiol redox-balance; therefore, by limiting H2O2 accumulation, glutathione peroxidases are also involved in modulating these processes. Several isozymes of this gene family exist in vertebrates, which vary in cellular location and substrate specificity. This isozyme is the most abundant, is ubiquitously expressed and localized in the cytoplasm, and whose preferred substrate is hydrogen peroxide. It is also a selenoprotein, containing the rare amino acid selenocysteine (Sec) at its active site. Sec is encoded by the UGA codon, which normally signals translation termination. The 3' UTRs of selenoprotein mRNAs contain a conserved stem-loop structure, designated the Sec insertion sequence (SECIS) element, that is necessary for the recognition of UGA as a Sec codon, rather than as a stop signal. This gene contains an in-frame GCG trinucleotide repeat in the coding region, and three alleles with 4, 5 or 6 repeats have been found in the human population. The allele with 4 GCG repeats has been significantly associated with breast cancer risk in premenopausal women. Alternatively spliced transcript variants have been found for this gene. Pseudogenes of this locus have been identified on chromosomes X and 21. [provided by RefSeq, Aug 2017]