Okada S, Rossmann M D, Brown E B
Biochim Biophys Acta. 1978 Sep 21;543(1):72-81. doi: 10.1016/0304-4165(78)90455-5.
The effect of acid pH and citrate on the exchange of iron between binding sites of rat transferrin has been studied. In the absence of citrate, diferric transferrin shows stepwise loss of iron atoms with the first atom of iron released at approximately pH 5.2. Citrate at physiologic concentrations (1.10(-3) M) or greater allows random iron removal at pH 6.5 or less. Iron dissociation from monoferric transferrin at acid pH, with or without citrate, is a random process. At pH 7.4, randomization of iron on transferrin takes from 3 to 6 h in the presence of millimolar concentrations of citrate. We conclude that at acid pH and in the presence of citrate concentrations likely to occur in vivo in the rat there is little scrambling of iron bound to transferrin.
研究了酸性pH值和柠檬酸盐对大鼠转铁蛋白结合位点间铁交换的影响。在没有柠檬酸盐的情况下，双铁转铁蛋白显示出铁原子的逐步丢失，第一个铁原子在大约pH 5.2时释放。生理浓度（1.10(-3) M）或更高的柠檬酸盐允许在pH 6.5或更低时随机去除铁。在酸性pH值下，无论有无柠檬酸盐，单铁转铁蛋白的铁解离都是一个随机过程。在pH 7.4时，在毫摩尔浓度的柠檬酸盐存在下，转铁蛋白上铁的随机化需要3到6小时。我们得出结论，在酸性pH值以及大鼠体内可能出现的柠檬酸盐浓度存在的情况下，与转铁蛋白结合的铁很少发生混乱。
