PROSTAGLANDIN H SYNTHASE PEROXIDATIC FORMATION OF N HYDROXY N ACETYL BENZIDINE

前列腺素H合酶（PHS）激活芳香胺 膀胱癌原N-乙酰联苯胺（ABZ）形成 N '-（3'-单磷酸-脱氧鸟苷-8-基）-N-乙酰基联苯胺和 4 '-硝基-4-乙酰氨基联苯（4-硝基-ABZ）。 前加合物是 被认为会导致突变，最终可能导致肿瘤 阵 本报告评估了3 H-ABZ（0.06 mM）的作用机制 PHS对绵羊精囊微粒体的过氧化激活作用 通过HPLC分析。 抗坏血酸抑制4-硝基-ABZ的形成 并增加了通过ESI/MS/MS鉴定的新峰， N '-羟基-N-乙酰基联苯胺（N' HA）。 N 'HA被观察到是否 花生四烯酸（0.2mM）或H2 O2（0.5mM）用作底物。 当存在未标记的0.05 mM N 'HA时，3 H-4-硝基-ABZ的减少 ~ 3 H-N ′ HA也相应增加。 PHS 将N 'HA定量转化为4-硝基-ABZ。 氰化物（10 mM），a 过氧化物酶抑制剂，阻止代谢，但细胞色素P-450 抑制剂SKF-525 A、呋喃茶碱或β-萘酮（0.1 mM） 没有 PHS代谢保泰松，但不是ABZ，证明 摄氧量 因此，N 'HA是过氧化物酶中的中间体。 激活ABZ的PHS，并可能参与形成的 DNA加合物。 这是第一份报告，以证明形成一个 N-OH芳胺通过过氧化物途径。

Prostaglandin H synthase (PHS) activates the aromatic amine bladder carcinogen N-acetylbenzidine (ABZ) to form N'-(3'-monophospho-deoxyguanosin-8- yl)-N-acetylbenzidine and 4'-nitro-4-acetylaminobiphenyl (4-nitro-ABZ). The former adduct is thought to cause mutations that may eventually lead to tumor formation. This report assesses the mechanism of 3H-ABZ (0.06 mM) peroxidatic activation by PHS, using ram seminal vesicle microsomes with analysis by HPLC. Ascorbic acid inhibits 4-nitro-ABZ formation and increases a new peak identified by ESI/MS/MS as N'-hydroxy-N-acetylbenzidine (N'HA). N'HA was observed whether arachidonic acid (0.2 mM) or H2O2 (0.5 mM) were used as the substrate. When unlabeled 0.05 mM N'HA was present, a decrease in 3H-4-nitro-ABZ and corresponding increase in 3H-N'HA was observed. PHS quantitatively converted N'HA to 4-nitro-ABZ. Cyanide (10 mM), a peroxidase inhibitor, prevented metabolism, but cytochrome P-450 inhibitors SKF-525A, furafyl line, or ( -naphthoflavone (0.1 mM) did not. PHS metabolism of phenylbutazone, but not ABZ, demonstrated oxygen uptake. Thus, N'HA is an intermediate in the peroxidatic activation of ABZ by PHS and may participate in the formation of the DNA adduct. This is the first report to demonstrate formation of an N-OH arylamine by a peroxidatic pathway.