Guengerich F P, Martin M V, Beaune P H, Kremers P, Wolff T, Waxman D J
J Biol Chem. 1986 Apr 15;261(11):5051-60.
The metabolism of the dihydropyridine calcium antagonist and vasodilator nifedipine has been reported to exhibit polymorphism among individual humans (Kleinbloesem, C. H., van Brummelen, P., Faber, H., Danhof, M., Vermeulen, N. P. E., and Breimer, D.D. (1984) Biochem. Pharmacol. 33, 3721-3724). Nifedipine oxidation has been shown to be catalyzed by cytochrome P-450 (P-450) enzymes. Reconstitution, immunoinhibition, and induction studies with rat liver indicated that the forms designated P-450UT-A and P-450PCN-E are the major contributors to microsomal nifedipine oxidation. The P-450 which oxidizes nifedipine (P-450NF) was purified to electrophoretic homogeneity from several human liver samples. Antibodies raised to P-450NF were highly specific as judged by immunoblotting analysis and inhibited greater than 90% of the nifedipine oxidase activity in human liver microsomes. A monoclonal antibody raised to the human P-450 preparation reacted with both human P-450NF and rat P-450PCN-E. Immunoblotting analysis of 39 human liver microsomal samples using anti-P-450NF antibodies revealed the same 52,000-dalton polypeptide, corresponding to P-450NF, with only one of the microsomal samples showing an additional immunoreactive protein. The level of nifedipine oxidase activity was highly correlated with the amount of P-450NF thus detected using either polyclonal (r = 0.78) or monoclonal (r = 0.65) antibodies, suggesting that the amount of the P-450NF polypeptide may be a major factor in influencing the level of catalytic activity in humans as well as rats. Cytochrome b5 enhanced the catalytic activity of reconstituted P-450NF, and anti-cytochrome b5 inhibited nifedipine oxidase activity in human liver microsomes. P-450NF also appears to be a major contributor to human liver microsomal aldrin epoxidation, d-benzphetamine N-demethylation, 17 beta-estradiol 2- and 4-hydroxylation, and testosterone 6 beta-hydroxylation, the major pathway for oxidation of this androgen in human liver microsomes.
据报道，二氢吡啶类钙拮抗剂和血管扩张剂硝苯地平在个体人类中的代谢存在多态性（Kleinbloesem, C. H., van Brummelen, P., Faber, H., Danhof, M., Vermeulen, N. P. E., and Breimer, D.D. (1984) Biochem. Pharmacol. 33, 3721 - 3724）。硝苯地平氧化已被证明由细胞色素P - 450（P - 450）酶催化。用大鼠肝脏进行的重组、免疫抑制和诱导研究表明，命名为P - 450UT - A和P - 450PCN - E的形式是微粒体硝苯地平氧化的主要贡献者。将氧化硝苯地平的P - 450（P - 450NF）从几个人类肝脏样本中纯化至电泳纯。通过免疫印迹分析判断，针对P - 450NF产生的抗体具有高度特异性，并抑制了人类肝脏微粒体中90%以上的硝苯地平氧化酶活性。针对人类P - 450制剂产生的单克隆抗体与人类P - 450NF和大鼠P - 450PCN - E均发生反应。使用抗P - 450NF抗体对39个人类肝脏微粒体样本进行免疫印迹分析，显示出相同的52,000道尔顿多肽，对应于P - 450NF，只有一个微粒体样本显示出额外的免疫反应性蛋白。硝苯地平氧化酶活性水平与使用多克隆抗体（r = 0.78）或单克隆抗体（r = 0.65）检测到的P - 450NF量高度相关，这表明P - 450NF多肽的量可能是影响人类和大鼠催化活性水平的主要因素。细胞色素b5增强了重组P - 450NF的催化活性，抗细胞色素b5抑制了人类肝脏微粒体中的硝苯地平氧化酶活性。P - 450NF似乎也是人类肝脏微粒体中艾氏剂环氧化、d - 苄非他明N - 去甲基化、17β - 雌二醇2 - 和4 - 羟基化以及睾酮6β - 羟基化的主要贡献者，睾酮6β - 羟基化是该雄激素在人类肝脏微粒体中氧化的主要途径。
