Morgan E H
Biochim Biophys Acta. 1979 Oct 24;580(2):312-26. doi: 10.1016/0005-2795(79)90144-2.
Iron release from human, rabbit, rat and sheep transferrin, chicken conalbumin and human lactoferrin was measured by the change in absorbance of solutions of the iron-protein complexes or by the release of 59Fe from the protein conjugated to agarose. Several phosphatic compounds and iron chelators were able to mediate the process (ATP, GTP, 2,3-diphosphoglycerate, inositol hexaphosphate, pyridoxal 5-phosphate, cytidine 5-triphosphate, pyrophosphate, inorganic phosphate, citrate, EDTA, oxalate, nitrilotriacetate). The greatest rate of iron release was found with pyrophosphate and the least with inorganic phosphate. Different rates of iron release were obtained with the different proteins, greatest with human transferrin and least with lactoferrin. With each of the proteins and the mediators there was a linera relationship between the H+ concentration and the rate of iron release. At any given pH the rate of iron release increased to a maximal rate as the mediator concentration was raised. It is concluded that iron release from transferrin under the conditions of these experiments involves an initial interaction between H+ and the iron-transferrin complex followed by release of the iron under the action of the mediator.
通过测量铁 - 蛋白质复合物溶液吸光度的变化或通过从与琼脂糖结合的蛋白质中释放⁵⁹Fe，来测定人、兔、大鼠和绵羊转铁蛋白、鸡伴清蛋白和人乳铁蛋白中铁的释放情况。几种磷酸化合物和铁螯合剂能够介导这一过程（ATP、GTP、2,3 - 二磷酸甘油酸、肌醇六磷酸、磷酸吡哆醛、胞苷 - 5 - 三磷酸、焦磷酸、无机磷酸盐、柠檬酸盐、EDTA、草酸盐、次氮基三乙酸）。发现焦磷酸介导的铁释放速率最高，无机磷酸盐介导的速率最低。不同蛋白质的铁释放速率不同，人转铁蛋白的释放速率最高，乳铁蛋白的最低。对于每种蛋白质和介导剂，H⁺浓度与铁释放速率之间呈线性关系。在任何给定的pH值下，随着介导剂浓度的升高，铁释放速率增加至最大速率。得出的结论是，在这些实验条件下，转铁蛋白中铁的释放涉及H⁺与铁 - 转铁蛋白复合物之间的初始相互作用，随后在介导剂的作用下铁被释放。
