Puppo A, Halliwell B
Department of Biochemistry, University of London King's College, U.K.
Biochem J. 1988 Jan 1;249(1):185-90. doi: 10.1042/bj2490185.
The ability of oxyhaemoglobin and methaemoglobin to generate hydroxyl radicals (OH.) from H2O2 has been investigated using deoxyribose and phenylalanine as 'detector molecules' for OH.. An excess of H2O2 degrades methaemoglobin, releasing iron ions that react with H2O2 to form a species that appears to be OH.. Oxyhaemoglobin reacts with low concentrations of H2O2 to form a 'reactive species' that degrades deoxyribose but does not hydroxylate phenylalanine. This 'reactive species' is less amenable to scavenging by certain scavengers (salicylate, phenylalanine, arginine) than is OH., but it appears more reactive than OH. is to others (Hepes, urea). The ability of haemoglobin to generate not only this 'reactive species', but also OH. in the presence of H2O2 may account for the damaging effects of free haemoglobin in the brain, the eye, and at sites of inflammation.
利用脱氧核糖和苯丙氨酸作为羟基自由基（OH.）的“检测分子”，研究了氧合血红蛋白和高铁血红蛋白从过氧化氢（H2O2）生成羟基自由基的能力。过量的H2O2会降解高铁血红蛋白，释放出铁离子，这些铁离子与H2O2反应形成一种似乎是OH.的物质。氧合血红蛋白与低浓度的H2O2反应形成一种“反应性物质”，该物质会降解脱氧核糖，但不会使苯丙氨酸羟基化。这种“反应性物质”比OH.更难被某些清除剂（水杨酸盐、苯丙氨酸、精氨酸）清除，但它对其他物质（羟乙基哌嗪乙磺酸、尿素）的反应性似乎比OH.更强。血红蛋白不仅能够在H2O2存在的情况下生成这种“反应性物质”，还能生成OH.，这可能解释了游离血红蛋白在大脑、眼睛和炎症部位造成的损伤作用。
