Otto-von-Guericke-Universität and MOLISA GmbH, Magdeburg, Germany.
Antioxid Redox Signal. 2011 Aug 1;15(3):763-80. doi: 10.1089/ars.2010.3397. Epub 2010 Nov 1.
Thiol peroxidases comprise glutathione peroxidases (GPx) and peroxiredoxins (Prx). The enzymes of both families reduce hydroperoxides with thiols by enzyme-substitution mechanisms. H(2)O(2) and organic hydroperoxides are reduced by all thiol peroxidases, most efficiently by SecGPxs, whereas fast peroxynitrite reduction is more common in Prxs. Reduction of lipid hydroperoxides is the domain of monomeric GPx4-type enzymes and of some Prxs. The catalysis starts with oxidation of an active-site selenocysteine (U(P)) or cysteine (C(P)). Activation of Cys (Sec) for hydroperoxide reduction in the GPx family is achieved by a typical tetrad composed of Cys (Sec), Asn, Gln, and Trp, whereas a triad of Cys Thr (or Ser) and Arg is the signature of Prx. In many of the CysGPxs and Prxs, a second Cys (C(R)) is required. In these 2-CysGPxs and 2-CysPrxs, the C(P) oxidized to a sulfenic acid forms an intra- or intermolecular disulfide (typical 2-CysPrx) with C(R), before a stepwise regeneration of ground-state enzyme by redoxin-type proteins can proceed. In SecGPxs and sporadically in Prxs, GSH is used as the reductant. Diversity combined with structural variability predestines thiol peroxidases for redox regulation via ROOH sensing and direct or indirect transduction of oxidant signals to specific protein targets.
硫氧还蛋白过氧化物酶包括谷胱甘肽过氧化物酶 (GPx) 和过氧化物酶 (Prx)。这两个家族的酶通过酶取代机制用硫醇还原过氧化物。所有的硫氧还蛋白过氧化物酶都能还原 H(2)O(2) 和有机过氧化物，SecGPx 还原效率最高，而过氧化物酶更常见于快速还原过亚硝酸根。脂类过氧化物的还原是单体 GPx4 型酶和一些过氧化物酶的领域。催化作用始于活性部位硒代半胱氨酸 (U(P)) 或半胱氨酸 (C(P)) 的氧化。GPx 家族中 Cys (Sec) 用于过氧化物还原的激活是通过典型的四联体组成的，包括 Cys (Sec)、Asn、Gln 和 Trp，而过氧化物酶的特征是三联体 Cys Thr (或 Ser) 和 Arg。在许多 CysGPxs 和 Prxs 中，需要第二个 Cys (C(R))。在这些 2-CysGPxs 和 2-CysPrxs 中，氧化为亚磺酸的 C(P) 与 C(R) 形成分子内或分子间二硫键（典型的 2-CysPrx），然后由 redoxin 型蛋白进行逐步再生，才能恢复到基础状态的酶。在 SecGPxs 和偶尔在 Prxs 中，GSH 用作还原剂。多样性与结构变异性相结合，使硫氧还蛋白过氧化物酶成为通过 ROOH 感应和直接或间接将氧化剂信号转导到特定蛋白质靶标进行氧化还原调节的理想选择。
