PEROXYGENASE METABOLISM OF N ACETYLBENZIDINE BY PROSTAGLANDIN H SYNTHASE

N‘-(3’-Monophospho-deoxyguanosin-8-yl)-N-acetylbenzidine(1A)是一个 联苯胺暴露的生物标记物，起始的最终产物，以及 会产生遗传毒性损伤。前列腺素H合成酶(PHS)激活 芳香胺类膀胱癌物质N-乙酰联苯胺(ABZ)的形成 1A.本报告探讨了ABZ的PHS代谢机制。 花生四烯酸(0.2 mM)与公羊精囊微球转化 ~3H-ABZ(0.06 mM)至4‘-硝基-4-乙酰氨基联苯(占总量的21% 新陈代谢用高效液相色谱测定)。与抗坏血酸，N‘-羟基-N-乙酰基联苯胺 (N‘Ha)是主要产物，经ESI/MS/MS鉴定。 用过氧化氢(0.3 mM)观察结果。氰化物(10毫米)，a 过氧化物酶抑制剂，阻止新陈代谢，但细胞色素P-450 缓蚀剂SKF-525A、呋喃茶碱或-萘黄酮(0.1 mM)起作用 不。DMPO的缺乏效果表明，自由基产品 未涉及电子转移所产生的影响。用双氧水，氧气 未检测到摄取。既不是羟基自由基也不是超氧化物 是氧结合的来源，因为甘露醇和超氧化物 歧化酶没有抑制作用。为了确定氧气的来源 加入到ABZ中，使用[18O]H_2O_2。18O-N‘Ha浓缩是 甲萘二酮与[18O]H_2O_2碱性氧化法的比较 18O-环氧化物。N‘Ha的富集度与环氧化物相似。因此，小灵通 通过过氧代谢代谢ABZ。N‘Ha可能在小灵通过程中形成1A ABZ的代谢。

N'-(3'-Monophospho-deoxyguanosin-8-yl)-N-acetylbenzidine (1A) is a biomarker of benzidine exposure, an endproduct of initiation, and produces genotoxic lesions. Prostaglandin H synthase (PHS) activates the aromatic amine bladder carcinogen N-acetylbenzidine (ABZ) to form 1A. This report examines the mechanism of PHS metabolism of ABZ. Arachidonic acid (0.2 mM) with ram seminal vesicle microsomes convert 3H-ABZ (0.06 mM) to 4'-nitro-4-acetylaminobiphenyl (21% of total metabolism by HPLC). With ascorbic acid, N'-hydroxy-N-acetylbenzidine (N'HA) was the major product and was identified by ESI/MS/MS. Similar results were observed with H2O2 (0.3 mM). Cyanide (10 mM), a peroxidase inhibitor, prevented metabolism, but cytochrome P-450 inhibitors SKF-525A, furafylline, or (-naphtho-flavone (0.1 mM) did not. The lack of effect of DMPO suggests that radical products generated by electron transfer were not involved. With H2O2, oxygen uptake was not detected. Neither h ydroxyl ra dicals nor superoxide are sources of oxygen incorporation, because mannitol and superoxide dismutase did not inhibit. To determine the source of oxygen incorporated into ABZ, [18O]H2O2 was used. 18O-N'HA enrichment was compared to [18O]H2O2 alkaline oxidation of menadione to its 18O-epoxide. N'HA enrichment was similar to the epoxide. Thus, PHS metabolizes ABZ by peroxygenation. N'HA may form 1A during PHS metabolism of ABZ.