二硫苏糖醇和氧自由基还原马脾铁蛋白释放铁的研究

用光谱法研究了二硫苏糖醇(DTT)还原马脾铁蛋白(HSF)释放铁的动力学．在空气(21％02)和反应时间为2h条件下，HSF释放铁的量比厌氧条件下高出126．9％一150．6％，释放速率快2—3倍．加入甘露醇和SOD均有明显抑制释放铁的速率，这一现象说明氧自由基的存在对释放铁起关键作用．在空气条件下DTT还原HsF释放铁的途径，可能同时存在DTT通过HsF蛋白壳上的8个横跨蛋白壳的亲水通道进入铁核的还原释放途径和HSF分子内产生的氧自由基对铁核的还原释放途径．

A Study on Reduction and Release of Iron from Horse Spleen Ferritin by Dithiothreitol and Oxygen Radicals

The kinetics of iron released from the ferric core of horse spleen ferritin (HSF) by dithiothreitol(DTT) was determined by electronic spectroscopy method. The amount of iron released from HSF ferric core under aerobic condition was 126.9% to 150.6% higher than that under anaerobic condition, and the releasing rate of iron is 2-3 times higher. The amount of released iron decreased greatly when manitol and superoxide dismutase were added, which demonstrated that the presence of oxygen radicals played a key role in the iron releasing. It was possible that the iron released from HSF by DTT under aerobic condition possessed two pathways, one was DTT getting through the channels into the cavity and reducing the ferric core directly, the other was iron released from HSF by oxygen radicals which were produced within the HSF molecule.