Structural gene products of the Ah locus. Genetic and immunochemical evidence for two forms of mouse liver cytochrome P-450 induced by 3-methylcholanthrene.
Structural gene products of the Ah locus. Genetic and immunochemical evidence for two forms of mouse liver cytochrome P-450 induced by 3-methylcholanthrene.
复制标题
Ah 基因座的结构基因产物。
DOI：
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发表时间：
1979
影响因子：
4.8
通讯作者：
D. Nebert
中科院分区：
文献类型：
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作者：
M. Negishi;D. Nebert
用异种对照（HS）小鼠，发现肝微粒体3-甲基胆蒽诱导的芳烃（苯并芘）羟化酶（EC 1.14.14.2）活性差异大于g倍，3-甲基胆蒽诱导的乙酰苯胺4-羟化酶活性差异至少4倍。这些数据有力地表明，已知与小鼠Ah位点相关的两种诱导细胞色素p -450介导的单加氧酶活性具有独立的遗传控制。本文描述了从经3-甲基胆蒽处理的C57BL/6N中分离两种部分分离的P-450的诱导形式的方法，并开发了针对这两种形式的抗体。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳，估计这两种部分分离的血红蛋白的分子量约为55,000。有限的蛋白质水解揭示了这两种细胞色素在肽组成上的差异。在苯并[a]芘存在的情况下，PI-450与多环芳香族化合物诱导的芳烃羟化酶活性和NADPH氧化密切相关，而P-448与多环芳香族化合物诱导的乙酰苯胺4-羟化酶活性和乙酰苯胺存在的NADPH氧化密切相关。PI-450和P-448的还原血红蛋白*CO复合物的Soret峰分别约为449.3 nm和448.0 nm。山羊抗pi -450免疫球蛋白抑制3-甲基胆蒽诱导的芳烃羟化酶活性，而不影响3-甲基胆蒽诱导的乙酰苯胺4-羟化酶活性。兔抗p -448免疫球蛋白阻断3-甲基胆碱诱导的乙酰苯胺4-羟化酶活性，而不影响3-甲基胆碱诱导的芳烃羟化酶活性。证据也提出了P-448可能存在于对照组，未经治疗的小鼠的肝微粒体中。采用磷酸吡啶醛/NaB[: ' H&法体外标记完整微粒体并进行免疫沉淀，证实2,3,7,8-四氯二苯并-对二恶英经胎盘诱导胎鼠肝脏PI-450（及其相关芳烃羟化酶活性）比2,3,7,8-四氯二苯并-对二恶英诱导P-448（及其相关乙酰苯胺4-羟化酶活性）在胎龄早期发生。这些数据，加上涉及体外抑制剂的研究，
With the use of heterogenic stock (HS) mice, more than g-fold differences in hepatic microsomal 3-methylcholanthrene-inducible aryl hydrocarbon (benzo[alpyrene) hydroxylase (EC 1.14.14.2) activity and at least 4-fold differences in 3-methylcholanthrene-inducible acetanilide 4-hydroxylase activity were found. These data strongly suggest independent genetic control of two inducible cytochrome P-450-mediated monooxygenase activities known to be associated with the murine Ah locus. The procedure is described for isolating two inducible forms of partially separated P-450 from C57BL/6N treated with 3-methylcholanthrene, and an antibody to each of these forms was developed. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a molecular weight of about 55,000 is estimated for both partially separated hemoproteins. Limited proteolysis reveals differences in the peptide composition of these two cytochromes. PI-450 is more closely associated with polycyclic aromatic compound-inducible aryl hydrocarbon hydroxylase activity and NADPH oxidation in the presence of benzo[a]pyrene, whereas P-448 is more closely associated with polycyclic aromatic compoundinducible acetanilide 4-hydroxylase activity and NADPH oxidation in the presence of acetanilide. The Soret peaks of the reduced hemoprotein*CO complex are about 449.3 and 448.0 nm for PI-450 and P-448, respectively. Goat anti-PI-450 immunoglobulin inhibits 3-methylcholanthrene-inducible aryl hydrocarbon hydroxylase activity while not affecting 3-methylcholanthrene-inducible acetanilide 4-hydroxylase activity. Rabbit anti-P-448 immunoglobulin blocks 3-methylcholanthrene-inducible acetanilide 4-hydroxylase activity while not affecting 3-methylcholanthrene-inducible aryl hydrocarbon hydroxylase activity. Evidence is also presented for the possible presence of P-448 in the liver microsomes of the control, untreated mouse. By means of the pyridoxal phosphate/NaB[:‘H& method for labeling intact microsomes in vitro followed by immunoprecipitation, it was confirmed that transplacental PI-450 induction (and its associated aryl hydrocarbon hydroxylase activity) in fetal mouse liver by 2,3,7,8-tetrachlorodibenzo-p-dioxin develops earlier in gestational age than P-448 induction (and its associated acetanilide 4-hydroxylase activity) by 2,3,7,8-tetrachlorodibenzo-p-dioxin. These data, plus studies involving inhibitors in vitro,