Saccoccia Fulvio, Angelucci Francesco, Boumis Giovanna, Desiato Gianni, Miele Adriana E, Bellelli Andrea
*Istituto Pasteur-Fondazione Cenci-Bolognetti and Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Rome, Italy.
†Dipartimento di Medicina clinica, sanità pubblica, scienze della vita e dell'ambiente, Piazzale Salvatore Tommasi 1, 67100 L'Aquila, Italy.
Biochem Soc Trans. 2014 Dec;42(6):1768-72. doi: 10.1042/BST20140212.
Peroxiredoxins (Prxs) and glutathione peroxidases (Gpxs) provide the majority of peroxides reducing activity in the cytoplasm. Both are peroxidases but differences in the chemical mechanism of reduction of oxidative agents, as well as in the reactivity of the catalytically active residues, confer peculiar features on them. Ultimately, Gpx should be regarded as an efficient peroxides scavenger having a high-reactive selenocysteine (Sec) residue. Prx, by having a low pKa cysteine, is less efficient than Gpx in reduction of peroxides under physiological conditions, but the chemistry of the sulfur together with the peculiar structural arrangement of the active site, in typical Prxs, make it suitable to sense a redox environment and to switch-in-function so as to exert holdase activity under redox-stress conditions. The complex macromolecular assembly would have evolved the chaperone holdase function and the moonlighting behaviour typical of many Prxs.
过氧化物酶（Prxs）和谷胱甘肽过氧化物酶（Gpxs）在细胞质中提供了大部分的过氧化物还原活性。它们都是过氧化物酶，但在氧化还原剂还原的化学机制以及催化活性残基的反应性方面存在差异，这赋予了它们独特的特性。最终，Gpx应被视为一种高效的过氧化物清除剂，具有高反应性的硒代半胱氨酸（Sec）残基。Prx由于其半胱氨酸的低pKa值，在生理条件下还原过氧化物的效率低于Gpx，但在典型的Prxs中，硫的化学性质以及活性位点的特殊结构排列使其适合感知氧化还原环境并切换功能，从而在氧化应激条件下发挥分子伴侣保留酶活性。这种复杂的大分子组装可能已经进化出了许多Prxs所特有的分子伴侣保留酶功能和兼职行为。
