辐射产生的血清白蛋白自由基对血红蛋白的损伤。

Puchała M, Szweda-Lewandowska Z

Department of Molecular Biophysics, University of Lódź, Poland.

Free Radic Biol Med. 1999 May;26(9-10):1284-91. doi: 10.1016/s0891-5849(98)00336-0.

We have studied the effects of the interaction of radiation generated human serum albumin radicals (HSA*) with human hemoglobin molecules (Hb). Diluted Hb aqueous solutions were irradiated under N2O or argon without HSA and in the presence of HSA. Analysis of Hb absorbance spectra in the visible range, cross-linking of HSA* radicals with Hb molecules and functional properties of Hb were investigated. The degree of Hb destruction estimated on the basis of changes in the absorption spectra indicated that the effectiveness of HSA* radicals generated under N2O for Hb destruction was approximately equal to that of OH radicals. In this case mainly OH radicals formed the secondary HSA radicals. However, during the irradiation Hb + HSA under argon the presence of equivalent amounts of oxidizing and reducing products of water radiolysis lowers the degree of Hb destruction. Some reactions of HSA radicals with Hb molecules lead to the formation of covalent bonds between the molecules of both proteins. The following types of hybrids could be distinguished: Hb monomer-HSA, Hb dimer-HSA and higher aggregates. Structural changes of Hb by HSA* radicals were reflected by alterations in the oxygen affinity (increase) and cooperativity (decrease) of Hb. The results obtained indicate that in the experimental systems studied, the HSA* radical reactions with Hb molecules are favoured over recombination reactions of HSA* radicals. On this basis one can suggest that in the studied systems Hb plays the role of an acceptor of radical energy located on HSA.

我们研究了辐射产生的人血清白蛋白自由基（HSA*）与人血红蛋白分子（Hb）相互作用的影响。在无HSA以及有HSA存在的情况下，分别在N₂O或氩气氛围下对稀释的Hb水溶液进行辐照。研究了可见范围内Hb吸收光谱、HSA自由基与Hb分子的交联以及Hb的功能特性。基于吸收光谱变化估算的Hb破坏程度表明，N₂O氛围下产生的HSA自由基对Hb破坏的有效性与OH自由基大致相当。在这种情况下，主要是OH自由基形成了次级HSA自由基。然而，在氩气氛围下辐照Hb + HSA时，水辐射分解产生的等量氧化产物和还原产物的存在降低了Hb的破坏程度。HSA自由基与Hb分子的一些反应导致两种蛋白质分子之间形成共价键。可区分出以下几种类型的杂合物：Hb单体 - HSA、Hb二聚体 - HSA以及更高聚集体。HSA自由基引起的Hb结构变化表现为Hb的氧亲和力（增加）和协同性（降低）的改变。所得结果表明，在所研究的实验体系中，HSA自由基与Hb分子的反应比HSA*自由基的重组反应更占优势。基于此可以推测，在所研究的体系中，Hb起到了位于HSA上的自由基能量受体的作用。