含铁离子的XO/HX体系对糖类分子氧化作用的ESR研究

用自旋俘获方法直接检测含铁的黄嘌呤氧化酶/次黄嘌呤体系中由糖产生的自由基,发现该体系中除了产生羟基自由基外,还产生烷(氧)基自由基,且糖的浓度越高,体系中产生的烷(氧)基自由基也越多.这表明含铁的黄嘌呤氧化酶/次黄嘌呤体系对糖类分子有氧化作用,且糖的浓度越高,氧化作用越强,对机体的损伤越大.应用含硒抗体酶可有效清除烷(氧)基自由基,显示出很强的抗氧化能力.

ESR Spin Trapping Studies on the Radicals Generated from Iron-containing System of Xathine Oxidase and Hypoxathine in the Presence of Saccharide Molecules

The free radicals generated from iron containing system of xathine oxidase and hypoxathine(Fe XO/HX) were directly detected by using spin trapping. It was found that not only O₂^-· and OH· but also alkyl or alkoxyl radicals(R· or RO·) were detected when saccharides such as glucose, fructose and sucrose were added into the Fe-XO/HXsystem. The amounts of R· or RO· were increased with the increase of saccharide-concentration added to the Fe-XO/HXsystem. The results showed that saccharide molecules were oxidized by the saccharide containing Fe-XO/HXsystem. R· or RO·has a long life time and they are liposoluble. Thus, they have more toxicity than hydrophilic O₂^-·and OH·because the active sites of biomolecules are closely related with lipophilic phase. It is worth mentioning that the results have provided an evidence for the hypothesis of "Eating excess sucrose facilitates aging".The R· or RO· radicals were effectively scavenged by selenium-containing abzyme, which displayed a powerful ability to antioxidize.