Van Steveninck J, Boegheim J P, Dubbelman T M, Van der Zee J
Sylvius Laboratories, Department of Medical Biochemistry, Leiden, The Netherlands.
Biochem J. 1988 Feb 15;250(1):197-201. doi: 10.1042/bj2500197.
Uroporphyrin I, haematoporphyrin and haematoporphyrin derivative had no effect on O2-. generation during oxidation of hypoxanthine by xanthine oxidase and on the formation of hydroxyl radicals (OH.) in the hypoxanthine/xanthine oxidase/Fe3+-EDTA/deoxyribose system. On the other hand, these porphyrins strongly inhibited O2-. formation in a horseradish peroxidase/H2O2/NADPH mixture, whereas they augmented OH. generation in this system after addition of Fe3+-EDTA. Experimental evidence suggests that these observations should be ascribed to the formation of a porphyrin anion radical in the horseradish peroxidase/NADPH system. The formation of this anion radical was confirmed by e.s.r. spectroscopy. This radical is apparently unable to reduce cytochrome c, but it can replace O2-. in the OH.-generating Haber-Weiss reaction.
尿卟啉I、血卟啉及血卟啉衍生物对黄嘌呤氧化酶催化次黄嘌呤氧化过程中O2-的生成以及在次黄嘌呤/黄嘌呤氧化酶/Fe3+-乙二胺四乙酸/脱氧核糖体系中羟自由基（OH·）的形成均无影响。另一方面，这些卟啉在辣根过氧化物酶/H2O2/烟酰胺腺嘌呤二核苷酸磷酸（NADPH）混合物中强烈抑制O2-的形成，而在加入Fe3+-乙二胺四乙酸后，它们却增强了该体系中OH·的生成。实验证据表明，这些观察结果应归因于在辣根过氧化物酶/NADPH体系中形成了卟啉阴离子自由基。通过电子自旋共振光谱法证实了该阴离子自由基的形成。此自由基显然不能还原细胞色素c，但它可在产生OH·的哈伯-维伊斯反应中取代O2-。
