Mammalian Cytochrome P450 Enzymes Catalyze the Phenol-coupling Step in Endogenous Morphine Biosynthesis
Mammalian Cytochrome P450 Enzymes Catalyze the Phenol-coupling Step in Endogenous Morphine Biosynthesis
复制标题
DOI：
10.1074/jbc.m109.011320
复制
发表时间：
2009-09-04
影响因子：
4.8
通讯作者：
Guengerich, F. Peter
中科院分区：
文献类型：
--
作者：
Grobe, Nadja;Zhang, Baichen;Guengerich, F. Peter
将猪肝中催化底物（R）-牛心果碱至salutaridine的酚偶联反应的细胞色素P450（P450）酶预先纯化至均一（Amann，T.，鲁什，P. H.，哈，H.，和Zenk，M. H.（1995）Heterocycles 40，425-440）。该反应被发现在（R）-牛心果碱和NADPH存在下由人P450 2D 6和3A 4催化，产生的不是单一产物，而是（-）-异吲哚啉、（-）-紫堇碱、（-）-pallidine和salutaridine，它们是罂粟植物中以及很可能也在哺乳动物中建立的吗啡的对位邻位偶联前体。（S）-网状番荔枝碱是两种P450酶的底物，产生酚偶联生物碱（-）-异吲哚、（-）-紫堇碱、（-）-pallidine和sinoacutine;这些都不是吗啡前体。在细胞色素B（5）存在下，以（R）-牛心果碱为底物，P450 2D 6和P450 3A 4的催化效率相似。酚偶联的机制尚未建立，但是，我们倾向于一个单一的铁氧化循环，以产生salutaridine和其他三个生物碱（R）-牛心果碱。形成的salutaridine的总产量可以提供在人神经母细胞瘤细胞培养物和小鼠脑组织中发现的10 nM浓度的吗啡。
A cytochrome P450 (P450) enzyme in porcine liver that catalyzed the phenol-coupling reaction of the substrate (R)-reticuline to salutaridine was previously purified to homogeneity (Amann, T., Roos, P. H., Huh, H., and Zenk, M. H. (1995) Heterocycles 40, 425-440). This reaction was found to be catalyzed by human P450s 2D6 and 3A4 in the presence of (R)-reticuline and NADPH to yield not a single product, but rather (-)-isoboldine, (-)-corytuberine, (-)-pallidine, and salutaridine, the paraortho coupled established precursor of morphine in the poppy plant and most likely also in mammals. (S)-Reticuline, a substrate of both P450 enzymes, yielded the phenol-coupled alkaloids (-)-isoboldine, (-)-corytuberine, (-)-pallidine, and sinoacutine; none of these serve as a morphine precursor. Catalytic efficiencies were similar for P450 2D6 and P450 3A4 in the presence of cytochrome b(5) with (R)-reticuline as substrate. The mechanism of phenol coupling is not yet established; however, we favor a single cycle of iron oxidation to yield salutaridine and the three other alkaloids from (R)-reticuline. The total yield of salutaridine formed can supply the 10 nM concentration of morphine found in human neuroblastoma cell cultures and in brain tissues of mice.