Department of Physiology, Medical Faculty, Selcuk University, Konya, Turkey.
Biol Trace Elem Res. 2018 May;183(1):22-31. doi: 10.1007/s12011-017-1119-7. Epub 2017 Aug 15.
Among the trace elements, zinc is one of the most used elements in biological systems. Zinc is found in the structure of more than 2700 enzymes, including hydrolases, transferases, oxyreductases, ligases, isomerases, and lyases. Not surprisingly, it is present in almost all body cells. Preserving the stability and integrity of biological membranes and ion channels, zinc is also an intracellular regulator and provides structural support to proteins during molecular interactions. It acts as a structural element in nucleic acids or other gene-regulating proteins. Metallothioneins, the low molecular weight protein family rich in cysteine groups, are involved significantly in numerous physiological and pathological processes including particularly oxidative stress. A critical role of metallothioneins (MT) is to bind zinc with high affinity and to serve as an intracellular zinc reservoir. By releasing free intracellular zinc when needed, MTs mediate the unique physiological roles of zinc. MT expression is induced by zinc elevation, and thus, zinc homeostasis is maintained. That MT mediates the effects of zinc, besides having strong radical scavenging effects, points to the critical part it plays in oxidative stress. The present review aims to give information on metallothioneins, which have critical importance in the metabolism and molecular pathways of zinc.
在微量元素中，锌是生物系统中使用最广泛的元素之一。锌存在于超过 2700 种酶的结构中，包括水解酶、转移酶、氧化还原酶、连接酶、异构酶和裂合酶。毫不奇怪，它几乎存在于所有的体细胞中。锌能保护生物膜和离子通道的稳定性和完整性，也是细胞内的调节剂，并在分子相互作用过程中为蛋白质提供结构支持。它在核酸或其他基因调节蛋白中充当结构元素。富含半胱氨酸的低分子量蛋白质家族——金属硫蛋白，在许多生理和病理过程中都有显著作用，包括特别的氧化应激。金属硫蛋白（MT）的一个关键作用是与锌高亲和力结合，并作为细胞内锌的储存库。当需要时，MT 通过释放游离的细胞内锌来介导锌的独特生理作用。MT 的表达受锌浓度升高的诱导，从而维持锌的体内平衡。MT 除了具有很强的自由基清除作用外，还介导锌的作用，这表明它在氧化应激中起着关键作用。本文综述旨在介绍金属硫蛋白在锌的代谢和分子途径中的重要作用。
