Cytochrome P-450 isozyme 1 from phenobarbital-induced rat liver: purification, characterization, and interactions with metyrapone and cytochrome b5.
Cytochrome P-450 isozyme 1 from phenobarbital-induced rat liver: purification, characterization, and interactions with metyrapone and cytochrome b5.
复制标题
来自苯巴比妥诱导的大鼠肝脏的细胞色素 P-450 同工酶 1：纯化、表征以及与美替拉酮和细胞色素 b5 的相互作用。
DOI：
10.1021/bi00289a035
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发表时间：
1983
期刊：
影响因子：
2.9
通讯作者：
Walsh,C
中科院分区：
文献类型：
--
作者：
Waxman,DJ;Walsh,C
David J.Waxman**和Christopher Walsh摘要：从苯巴比妥(PB)诱导的大鼠肝微粒体中纯化了细胞色素P-450同工酶1(PB-1)(Mr AT53000)，并测定了其光谱、结构、免疫化学和催化性质。在未诱导的大鼠肝微粒体中存在大量的PB-1，苯巴比妥可诱导PB-1的~2-4倍，而之前描述的主要PB同工酶的典型诱导是>；30倍。PB-1不同于PB诱导的主要同工酶PB-4和PB-5[Wax-man，DJ，&Walsh，C.(1982)J.Biol]。化学。257,10446-10457]由于缺乏Fe2+-甲替拉酮P446复合体，其独特的氨基末端序列和独特的肽图，缺乏对PB-4的免疫交叉反应，以及其特有的底物专一性。在重组系统[GB m(metyra-pone)200*TM]中，美替拉酮对PB-1催化的几个反应有饱和的促进作用，其大小随着亚肝微体细胞色素P-4501催化一系列亲脂底物的氧化代谢而变化，包括药物、杀虫剂和碳氢化合物污染物，以及内源性类固醇和脂肪酸(Lu&West，1978；Wislocki等，1980)。单个生物体进行这些氧化转化的能力可以通过暴露于数百种单加氧酶诱导剂中的任何一种来调节(Conney，1967)，其中几种已被证明可以诱导特定形式或同工酶的P-450的从头生物合成，每一种都显示出广泛且重叠的底物特异性图谱(Guengerich，1979；Lu&West，1980)。大鼠肝脏经苯巴比妥、3-甲基胆蒽和其他多环化合物诱导的主要P-450同工酶已被纯化并得到很好的鉴定(Guengerich，1977,1978；Masuda-Mikawa等人，1979；Ryan等人，1979；West等人，1979)，以及从兔肝中分离出的相应形式(Haugen&Coon，1976)。此外，从异黄樟素或某些氯化联苯诱导的大鼠肝微体(Ryan等人，1980；Fisher等人，1981；Goldstein等人，1982)以及合成类固醇(Elshourbagy&Guzelian，1980)诱导的微体中已经纯化了不同形式的P-450。尽管几种诱导形式的P-450已经被提纯并得到了很好的鉴定，但生化和免疫化学分析都表明存在其他尚未鉴定的P-450同工酶
David J. Waxman** and Christopher Walsh abstract: Cytochrome P-450 isozyme 1 (PB-1)(Mr at53 000) was purified to apparent homogeneity from pheno-barbital (PB)-induced rat liver microsomes, and its spectral, structural, immunochemical, and catalytic properties were determined. PB-1, present in significant amounts in uninduced rat liver microsomes, is induced~2-4-fold by phenobarbital, as compared to the> 30-fold induction typical of the major PB isozymes characterized previously. PB-1 was distinguished from the major PB-induced isozymes PB-4 and PB-5 [Wax-man, DJ, & Walsh, C.(1982) J. Biol. Chem. 257, 10446-10457] by theabsence of a Fe2+-metyrapone P446 complex, by its unique NH2-terminal sequence and distinct peptide maps, by the lack of immuno-cross-reactivity to PB-4, and by itscharacteristic substrate-specificity profile. Metyrapone effected a saturable enhancement of several PB-1-catalyzed reactions in the reconstituted system [£ m (metyra-pone) 200* tM], which varied in magnitude with the sub-Hepatic microsomal cytochrome P-4501 catalyzesthe ox-idative metabolism of a braod range of lipophilic substrates including drugs, insecticides, and hydrocarbon pollutants, as well as endogenous steroids and fatty acids (Lu & West, 1978; Wislocki et al., 1980). The capacity of an individual organism for these oxidative transformations can be modulated by ex-posure to any of several hundred monooxygenase inducers (Conney, 1967), several of which have been shown to induce the de novo biosynthesis of specific forms or isozymes of P-450, each of which displays broad and overlapping substrate-spe-cificity profiles (Guengerich, 1979; Lu & West, 1980). The major rat liver P-450isozymes induced by phenobarbital and by 3-methylcholanthrene and other polycyclics have been purified and are well characterized (Guengerich, 1977, 1978; Masuda-Mikawa et al., 1979; Ryan et al., 1979; West et al., 1979), as are corresponding forms isolated from rabbit liver (Haugen & Coon, 1976). Additional, distinct forms of P-450 have been purified from rat liver microsomes induced with isosafrole or certain chlorinated biphenyls (Ryan et al., 1980; Fisher et al., 1981; Goldstein et al., 1982), as well as from microsomes induced with synthetic steroids (Elshourbagy & Guzelian, 1980). Although several induced forms of P-450 have thus been purified and are well characterized, both biochemical and immunochemical analyses indicate the presence of additional, yet to be characterized P-450 isozymes