PARTICIPATION OF CYTOCHROME B5 IN ANESTHETIC METABOLISM

细胞色素 B5 参与麻醉代谢

基本信息

批准号：
3288451
负责人：
LUCY A WASKELL
金额：
$ 23.59万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
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

项目摘要

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.

该提案的长期目标是通过以下方式了解该机制：哪些药物代谢和微粒体生物合成反应调节一种其他。该过程通过两个微粒体的相互作用发生电子传递链，其中细胞色素 P-450 和细胞色素 b5 成分。有证据表明这种相互作用发生在微粒体中并且在使用纯化酶的重构系统中。我的实验室有证明细胞色素 b5 在微粒体和细胞中都是必需的纯化的重组细胞色素 P-450 系统用于代谢挥发性麻醉剂甲氧氟烷。我实验室的初步数据还表明甲氧氟烷抑制胆固醇的合成，已知需要细胞色素 b5 的物质，其未知但可能显着的体内后果。该项目的近期目标有三个。一、作用细胞色素 b5 在挥发性麻醉剂氟烷代谢中的作用将探索安氟醚和异氟醚。卤代酸代谢物挥发性麻醉剂将被衍生化；卤代酸衍生物将是通过气相色谱法与干扰物质分离并定量通过质谱分析。第二个目标是阐明化学物质蛋白质修饰剂使细胞色素b5失活的基础，焦碳酸二乙酯。实验的目的是首先确定哪些氨基酸被修饰，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 更容易抑制甲氧氟烷代谢苯巴比妥诱导的肝脏微粒体高于肺微粒体。细胞色素 b5 和来自肝脏和肺的细胞色素 P-450 LM2 将被纯化、表征并进行了比较。完成先前概述的实验将极大地有助于我们了解影响因素细胞色素 P-450 和细胞色素 b5 之间的相互作用。