PARTICIPATION OF CYTOCHROME B5 IN ANESTHETIC METABOLISM

细胞色素 B5 参与麻醉代谢

• 批准号: 3288457
• 负责人: LUCY A WASKELL
• 金额: $ 19.86万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-07-01 至 1993-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3288457
• 关键词: NAD(P)H dehydrogenase; NADPH cytochrome c2 reductase; anesthetics; cholesterol; cyclic compound; cytochrome P450; cytochrome b; cytochrome b5 reductase; drug metabolism; electron transport; enflurane; gas chromatography; halothane; isoflurane; laboratory rabbit; lysine; mass spectrometry; methoxyflurane; microsomes; physical chemical interaction; unspecific monooxygenase

The long term objective of this proposal is to understand the mechanism by which drug metabolism and microsomal biosynthetic reactions modulate one another. The process occurs via an interaction of the two microsomal electron transport chains of which cytochrome P-450 and cytochrome b5 are components. Evidence exists that such interaction occurs in microsomes and in a reconstituted system employing purified enzymes. My laboratory has demonstrated that cytochrome b5 is required both in microsomes and in a purified reconstituted cytochrome P-450 system for the metabolism of the volatile anesthetic methoxyflurane. Preliminary data from my laboratory also indicate that methoxyflurane inhibits the synthesis of cholesterol, a substance which is known to require cytochrome b5 with unknown but possibly substantial in vivo consequences. The immediate goals of this project are three-fold. First, the role of cytochrome b5 in the metabolism of the volatile anesthetics, halothane, enflurane and isoflurane will be explored. The haloacid metabolites of the volatile anesthetics will be derivatized; the haloacid derivatives will be separated from interfering substances by gas chromatography and quantitated by mass spectrometry. The second objective is to elucidate the chemical basis of the inactivation of cytochrome b5 by the protein modifying agent, diethylpyrocarbonate. The experiments will be designed to first determine which amino acid(s) is modified and then determine the exact location of the amino acid in the protein. Our third and final short term aim is to determine the molecular basis for our observation that antibodies to cytochrome b5 inhibit methoxyflurane metabolism much more readily in phenobarbital induced liver than in lung microsomes. Cytochrome b5 and cytochrome P-450 LM2 from liver and lung will be purified, characterized and compared. Completion of the previously outlined experiments will significantly contribute to our knowledge of the factors which govern the interactions between cytochrome P-450 and cytochrome b5.

这项建议的长期目标是通过 药物代谢和微生物体生物合成反应中的哪一种 又一个。这一过程通过两个微体的相互作用发生。 细胞色素P-450和细胞色素b5是其电子传递链 组件。有证据表明，这种相互作用发生在微生物体和 在使用纯化酶的重组系统中。我的实验室有 证明了细胞色素b5在微生物体和 纯化重组细胞色素P-450系统对细胞色素P-450的代谢 挥发性麻醉剂甲氧氟烷。来自我的实验室的初步数据 还表明甲氧基氟烷抑制胆固醇的合成，a 已知需要细胞色素b5的物质，未知但可能 在活体内产生重大后果。 这个项目的近期目标有三个方面。第一，政府的角色 细胞色素b5在挥发性麻醉剂氟烷的代谢中， 将探索安氟醚和异氟醚。其卤代谢物 挥发性麻醉剂将被衍生化；卤素酸衍生物将被 气相色谱从干扰物质中分离并定量 通过质谱分析。第二个目标是阐明这种化学物质 根据蛋白质修饰剂使细胞色素b5失活的基础， 焦碳酸二乙酯。这些实验将首先被设计成确定 哪个氨基酸(S)被修饰，然后确定其确切位置 蛋白质中的氨基酸。我们的第三个也是最后一个短期目标是 确定我们观察到的抗体的分子基础 细胞色素b5更容易抑制甲氧基氟烷的代谢 苯巴比妥对肝脏的诱导作用大于对肺微粒体的诱导作用。细胞色素b5和 将从肝脏和肺中提纯细胞色素P-450 LM2，并对其进行鉴定 并进行了比较。完成前面概述的实验将 极大地促进了我们对支配 细胞色素P-450与细胞色素b5的相互作用。