Recombinant cytochrome P450 2D18 metabolism of dopamine and arachidonic acid.
Recombinant cytochrome P450 2D18 metabolism of dopamine and arachidonic acid.
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发表时间：
2000-09
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通讯作者：
C. Thompson;J. Capdevila;H. Strobel
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作者：
C. Thompson;J. Capdevila;H. Strobel
细胞色素P450（P450）在哺乳动物脑中的功能尚未完全了解。为了进一步理解这一点，本研究确定了P450 2D 18的两种内源性底物。以前的报道表明，这种异构体在大鼠脑中表达，重组酶催化抗抑郁药丙咪嗪和地昔帕明的N-去甲基化。通过进一步检查P450 2D 18的底物谱，可以推断潜在的内源性P450底物。在这里，我们证明了代谢的中枢神经系统作用的化合物氯丙嗪和氯唑沙宗的营业额为1.8和0。9 nmol/min/nmol。由于上述四种药物底物通过与神经递质受体结合而起作用，因此进行结合测定和氧化反应以测试多巴胺是否是P450 2D 18的底物。这些数据表明K（S）值为678 μ M，P450 2D 18可以通过过氧化物分流机制支持多巴胺氧化为氨基铬。我们还报道了P450 2D 18介导的花生四烯酸的ω-羟基化和环氧化，主要导致形成8，9-、11，12-和14，15-环氧二十碳三烯酸，这些化合物已被证明在脑、肾和心脏组织中具有血管活性。本文提供的数据表明，P450参与膜和受体调节通过epoxyeicosatrienoic acid形成和潜在的参与多巴胺氧化为活性氧物质在异常的生理条件下，多巴胺的螯合变得妥协，如在帕金森氏病的可能作用。
The function of cytochrome P450 (P450) in the mammalian brain is not well understood. In an effort to further this understanding, this study identifies two endogenous substrates for P450 2D18. Previous reports have shown that this isoform is expressed in the rat brain, and the recombinant enzyme catalyzes the N-demethylation of the antidepressants imipramine and desipramine. By further examining the substrate profile of P450 2D18, inferences can be made as to potential endogenous P450 substrates. Herein we demonstrate the metabolism of the central nervous system-acting compounds chlorpromazine and chlorzoxazone with turnover numbers of 1.8 and 0. 9 nmol/min/nmol, respectively. Because the four aforementioned pharmaceutical substrates work by binding to neurotransmitter receptors, binding assays and oxidation reactions were performed to test whether dopamine is a substrate for P450 2D18. These data indicate a K(S) value of 678 microM and that P450 2D18 can support the oxidation of dopamine to aminochrome through a peroxide-shunt mechanism. We also report the P450 2D18-mediated omega-hydroxylation and epoxygenation of arachidonic acid, primarily leading to the formation of 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids, compounds that have been shown to have vasoactive properties in brain, kidney, and heart tissues. The data presented herein suggest a possible role for P450 involvement in membrane and receptor regulation via epoxyeicosatrienoic acid formation and a potential involvement of P450 in the oxidation of dopamine to reactive oxygen species under aberrant physiological conditions where the sequestering of dopamine becomes compromised, such as in Parkinson's disease.