血红素与马脾铁蛋白的结合及其对铁释放速率的影响。
Haem binding to horse spleen ferritin and its effect on the rate of iron release.
作者信息
Kadir F H, al-Massad F K, Moore G R
机构信息
Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences, University of East Anglia, Norwich, U.K.
出版信息
Biochem J. 1992 Mar 15;282 ( Pt 3)(Pt 3):867-70. doi: 10.1042/bj2820867.
Horse spleen ferritin is shown to bind haem to generate a haemoprotein, named herein haemoferritin. A total of 14-16 haem molecules are bound per 24 subunits of ferritin. The molecular mass of the non-haem-iron-free haemoferritin has been determined to be 420 +/- 40 kDa, indicating that haem binding does not lead to dissociation of the 24 subunits that comprise the ferritin molecule. The functional role of the bound haem has been investigated with respect to the release of iron from the non-haem iron core. The bound haem is shown to increase the rate of iron release in a reductive assay system. In the absence of haem the rate of iron release depends on the redox potential of the reductant, but in the presence of haem the rate is largely independent of the reductant and is faster than the rate for the haem-free ferritin. These data haem, but in the presence of haem electron transfer is not rate-limiting.
已证明马脾铁蛋白能结合血红素生成一种血红蛋白，在此命名为血铁蛋白。每24个铁蛋白亚基结合14 - 16个血红素分子。已确定无血红素铁的血铁蛋白的分子量为420±40 kDa，这表明血红素结合不会导致构成铁蛋白分子的24个亚基解离。已针对非血红素铁核心中铁的释放研究了结合血红素的功能作用。在还原测定系统中，结合的血红素显示会增加铁的释放速率。在没有血红素的情况下，铁的释放速率取决于还原剂的氧化还原电位，但在有血红素的情况下，该速率在很大程度上与还原剂无关，并且比无血红素铁蛋白的速率更快。这些数据表明，在有血红素的情况下，电子转移不是限速步骤。
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