In vitro evaluation of potential in vivo probes for human flavin-containing monooxygenase (FMO): metabolism of benzydamine and caffeine by FMO and P450 isoforms.
In vitro evaluation of potential in vivo probes for human flavin-containing monooxygenase (FMO): metabolism of benzydamine and caffeine by FMO and P450 isoforms.
复制标题
人含黄素单加氧酶 (FMO) 潜在体内探针的体外评估：FMO 和 P450 亚型对苯甲胺和咖啡因的代谢。
DOI：
10.1046/j.1365-2125.2000.00265.x
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发表时间：
2000
影响因子：
3.4
通讯作者：
Rettie,AE
中科院分区：
文献类型：
--
作者：
Lang,DH;Rettie,AE
AimsTo确定FMO和P450异构体的选择性代谢的苄达明和咖啡因，两个潜在的活体探针人FMO.MethodsMetabolic孵育进行在生理pH值使用底物浓度为0.01-10 mM的重组人FMOs，P450或人肝微粒体作为酶源。 通过反相高效液相色谱法分析咖啡因和苄达明代谢产物。结果CYP 1A 2对咖啡因代谢有催化作用，而人FMOs对咖啡因代谢无催化作用。相反，苄达明是人FMO 1、FMO 3、FMO 4和FMO 5的底物。FMO 1、FMO 3、FMO 4和FMO 5的苄达明N-氧合表观Km值分别为60 ± 8 µm、80 ± 8 µm、> 3 mm和> 2 mm。 相应的Vmax值分别为46 ± 2 min−1、36 ± 2 min−1、<75 min− 1和<1 min−1。 CYP 1A 1、1A 2、2C 19、2D 6和3A 4也能生成少量苄达明N-氧化物。结论FMO 1和FMO 3催化苄达明N-氧化效率最高。然而，肝FMO 3的代谢能力可能比肝外FMO 1对体内血浆N-氧化物代谢水平的贡献更大。因此，苄达明，而不是咖啡因，是一个潜在的人FMO 3的体内探针。
AimsTo determine the FMO and P450 isoform selectivity for metabolism of benzydamine and caffeine, two potentialin vivoprobes for human FMO.MethodsMetabolic incubations were conducted at physiological pH using substrate concentrations of 0.01–10 mmwith either recombinant human FMOs, P450s or human liver microsomes serving as the enzyme source. Products of caffeine and benzydamine metabolism were analysed by reversed‐phase h.p.l.c. with u.v. and fluorescence detection.ResultsCYP1A2, but none of the human FMOs, catalysed metabolism of caffeine. In contrast, benzydamine was a substrate for human FMO1, FMO3, FMO4 and FMO5. ApparentKmvalues for benzydamineN‐oxygenation were 60 ± 8 µm, 80 ± 8 µm, > 3 mmand > 2 mm, for FMO1, FMO3, FMO4 and FMO5, respectively. The correspondingVmaxvalues were 46 ± 2 min−1, 36 ± 2 min−1, < 75 min−1and < 1 min−1. Small quantities of benzydamineN‐oxide were also formed by CYPs 1A1, 1A2, 2C19, 2D6 and 3A4.ConclusionsFMO1 and FMO3 catalyse benzydamineN‐oxygenation with the highest efficiency. However, it is likely that the metabolic capacity of hepatic FMO3 is a much greater contributor to plasma levels of theN‐oxide metabolitein vivothan is extrahepatic FMO1. Therefore, benzydamine, but not caffeine, is a potentialin vivoprobe for human FMO3.