Scavengers for Peroxynitrite: Inhibition of Tyrosine Nitration and Oxidation with Tryptamine Derivatives, .ALPHA.-Lipoic Acid and Synthetic Compounds.
作者:Hidehiko NAKAGAWA、Erika SUMIKI、Mitsuko TAKUSAGAWA、Nobuo IKOTA、Yoshikazu MATSUSHIMA、Toshihiko OZAWA
DOI:10.1248/cpb.48.261
日期:——
The inhibitory effects of various endogenous and synthetic compounds on the nitration and oxidation of L-tyrosine by peroxynitrite were examined. Nitrating and oxidizing activities were monitored by the formation of 3-nitrotyrosine and dityrosine with a HPLC-UV-fluorescence detector system, respectively. Glutathione, seroninand synthetis sulfur- and selenium-containing compounds inhibited both the nitration and oxidation reaction of L-tyrosine effectively. However, 5-methosytryptamine, melatonin and α-lipoic acid only inhibited the nitration reaction, and enhanced the formation of an oxidation product. This is important evidence that there are different intermediates in the nitrating and oxidizing reactions of L-tyrosine by peroxynitrite. It was suggested that 5-methoxytryptamine, melatonin and α-lipoic acid reacted only with the nitrating intermediate of peroxynitrite and inhibited nitration of L-tyrosine. Actually, the DNA stand breakage, which is believed to be a typical reaction of hydroxyl radical-like species, caused by peroxynitrite was not effectively ionhibited by 5-methoxytryptamine. 5-Methoxytryptamine, melatonin and α-lipoic acid were viewed as useful reagents for investigating the mechanisms of damage by peroxynitrite in vitro.
研究了各种内源性和合成化合物对过氧亚硝酸盐硝化和氧化 L-酪氨酸的抑制作用。使用 HPLC-UV-荧光检测器系统分别通过 3-硝基酪氨酸和二酪氨酸的形成来监测硝化和氧化活性。谷胱甘肽、血清素以及合成的含硫、硒化合物均能有效抑制L-酪氨酸的硝化和氧化反应。然而,5-甲基色胺、褪黑激素和α-硫辛酸仅抑制硝化反应,并增强氧化产物的形成。这是证明过亚硝酸盐对L-酪氨酸的硝化和氧化反应中存在不同中间体的重要证据。表明5-甲氧基色胺、褪黑激素和α-硫辛酸仅与过氧亚硝酸盐的硝化中间体发生反应,并抑制L-酪氨酸的硝化。实际上,由过氧亚硝酸盐引起的DNA断裂被认为是类羟基自由基物质的典型反应,但5-甲氧基色胺并不能有效地离子抑制。 5-甲氧基色胺、褪黑激素和α-硫辛酸被认为是研究体外过氧亚硝酸盐损伤机制的有用试剂。