论文部分内容阅读
本文利用高强度的同步辐射X光源及荧光探测技术研究铁蛋白中铁K吸收边的XANES,较准确地测定FeSO_4及Fe(NO_3)_3溶液中水合铁离子的K吸收边,其1s到5t_(1u)、7t_(1u)和连续态跃迁的化学位移之差值分别为1.3、4.5和6.2eV,以这两种价态的铁吸收边谱为标准,对同时含有二价和三价铁的样品的X光吸收近边谱进行数值拟合,定量地研究铁价态的变化,实验结果表明在铁蛋白重组过程中,低的pH值和高的铁浓度相应于慢的氧化速度,能够结合到蛋白壳上的锌等对氧化有很大的阻碍作用。能量色散EXAFS技术考察铁蛋白在还原过程中结构和Fe~(3+)的浓度变化,结果表明天然铁蛋白比重组铁蛋白要稳定得多。在铰蛋白重组过程中,吸收边的边前结构趋于明显,铁由正常六氧八面体配位过渡到与蛋白结合的不对称配位状态,同时吸收边后的肩峰逐渐突起,说明铁氧原子簇的长大,由单核变为多核,形成铁蛋白中的含铁中心。
In this paper, the high-intensity synchrotron X-ray source and fluorescence detection techniques were used to study the XANES of ferritin in the absorption side of iron K. The more accurate determination of the K absorption edge of the hydrated iron ions in FeSO_4 and Fe (NO_3) _3 solutions was carried out for 1s to 5t_ ), 7t_ (1u) and the chemical shifts of the continuous transitions are 1.3, 4.5 and 6.2eV, respectively. Based on the iron absorption edge spectra of these two valence states, the samples containing both divalent and ferric iron The results show that during the process of ferritin recombination, the low pH value and high iron concentration correspond to the slow oxidation rate, which can be combined with Zinc on the protein shell has a great impediment to oxidation. The energy dispersive EXAFS technology examines the ferritin structure and Fe ~ (3 +) concentration changes during the reduction process, the results show that natural ferritin than recombinant ferritin to be much more stable. In the process of reorganization of the hinge, the edge structure of the absorption side tends to be obvious. The transition of the iron from the normal hexaoctahedral coordination to the asymmetric coordination of the protein binding, and the gradual rise of the acromion behind the absorption side, Oxygen cluster growth, from mononuclear into multi-core, ferritin in the formation of iron center.