Radi R, Rubbo H, Thomson L, Prodanov E
Department of Biochemistry, Faculty of Medicine, University of the Republic, Montevideo, Uruguay.
Free Radic Biol Med. 1990;8(2):121-6. doi: 10.1016/0891-5849(90)90084-v.
Luminol chemiluminescence induced by the xanthine or hypoxanthine-O2-xanthine oxidase system is analyzed and compared. Characteristics of the light emission curves were examined considering the conventional reaction scheme for the oxidation of both substrates in the presence of xanthine oxidase. The ratio of the areas of the rate of superoxide production during substrate oxidation to uric acid. The O2-. to uric acid ratio for each substrate can account for differences in xanthine and hypoxanthine-supported light emission, since uric acid is a strong inhibitor of O2-.-dependent luminol chemiluminescence. These results are consistent with a free radical scavenging role for uric acid. A similar but weaker scavenging effect of xanthine may also contribute to the observed differences in chemiluminescent yields between both substrates.
对由黄嘌呤或次黄嘌呤 - O₂ - 黄嘌呤氧化酶系统诱导的鲁米诺化学发光进行了分析和比较。考虑到在黄嘌呤氧化酶存在下两种底物氧化的传统反应方案，研究了发光曲线的特征。底物氧化过程中超氧化物产生速率与尿酸的面积比。每种底物的O₂⁻与尿酸的比率可以解释黄嘌呤和次黄嘌呤支持的发光差异，因为尿酸是O₂⁻依赖性鲁米诺化学发光的强抑制剂。这些结果与尿酸的自由基清除作用一致。黄嘌呤类似但较弱的清除作用也可能导致两种底物之间观察到的化学发光产率差异。
