Boradia Vishant Mahendra, Raje Manoj, Raje Chaaya Iyengar
*National Institute of Pharmaceutical Education and Research (NIPER), Phase X, Sector 67, SAS Nagar, Punjab 160062, India.
†Institute of Microbial Technology, Sector 39 A, Chandigarh 160036, India.
Biochem Soc Trans. 2014 Dec;42(6):1796-801. doi: 10.1042/BST20140220.
Iron is essential for the survival of both prokaryotic and eukaryotic organisms. It functions as a cofactor for several vital enzymes and iron deprivation is fatal to cells. However, at the same time, excess amounts of iron are also toxic to cells due to the formation of free radicals via the Fenton reaction. As a consequence of its double-edged behaviour, the uptake and regulation of iron involves an intricate balance of acquisition, trafficking, recycling and shuffling between various tissues and organs. This is accomplished by differential regulation of genes involving numerous proteins and enzymes. Several of the proteins identified in these processes, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), aconitase and lactoferrin (Lf), possess multiple functions within the cell. Such proteins are referred to as moonlighting or multifunctional proteins, whereby proteins initially thought to possess a single well-established function have subsequently been discovered to exhibit alternative functions. In many cases, these multiple functions are conserved across species.
铁对于原核生物和真核生物的生存至关重要。它作为几种重要酶的辅助因子发挥作用，缺铁对细胞是致命的。然而，与此同时，过量的铁由于通过芬顿反应形成自由基，对细胞也是有毒的。由于其双刃剑的特性，铁的摄取和调节涉及到在各种组织和器官之间获取、运输、循环和重新分配的复杂平衡。这是通过对涉及众多蛋白质和酶的基因进行差异调节来实现的。在这些过程中鉴定出的几种蛋白质，如甘油醛-3-磷酸脱氢酶（GAPDH）、乌头酸酶和乳铁蛋白（Lf），在细胞内具有多种功能。这类蛋白质被称为兼职或多功能蛋白质，即最初被认为具有单一明确功能的蛋白质后来被发现具有其他功能。在许多情况下，这些多种功能在物种间是保守的。
