2-STEP EPOXIDATION OF HYOSCYAMINE TO SCOPOLAMINE IS CATALYZED BY BIFUNCTIONAL HYOSCYAMINE 6-BETA-HYDROXYLASE
2-STEP EPOXIDATION OF HYOSCYAMINE TO SCOPOLAMINE IS CATALYZED BY BIFUNCTIONAL HYOSCYAMINE 6-BETA-HYDROXYLASE
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DOI：
10.1016/0014-5793(93)80187-y
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发表时间：
1993-08-23
期刊：
影响因子：
3.5
通讯作者：
YAMADA, Y
中科院分区：
文献类型：
--
作者：
HASHIMOTO, T;MATSUDA, J;YAMADA, Y
在几种茄科植物中，莨菪碱首先在6 β位羟基化，然后环氧化为东莨菪碱。我们在大肠杆菌中表达了与麦芽糖结合蛋白融合的莨菪碱6 β-羟化酶（H6 H）。从表达可溶性融合蛋白的细菌的粗细胞提取物显示出强的羟化酶活性和弱的环氧酶活性。当100 μ M莨菪碱被喂入重组细菌时，生物碱首先转化为6 β-羟基莨菪碱，然后转化为东莨菪碱，东莨菪碱几乎是一周后在培养物中发现的唯一生物碱。因此，H6 H催化将莨菪碱氧化为东莨菪碱的两个连续反应。
In several solanaceous plants, hyoscyamine is first hydroxylated at the 6beta-position, and then epoxidized to scopolamine. We expressed hyoscyamine 6beta-hydroxylase (H6H) in Escherichia coli as a fusion protein with maltose-binding protein. The crude cell extract from the bacterium that expressed the soluble fusion protein showed a strong hydroxylase activity and a weak epoxidase activity. When 100 muM of hyoscyamine was fed to the recombinant bacterium, the alkaloid was first converted to 6beta-hydroxyhyoscyamine, and then to scopolamine, which was almost the only alkaloid found in the culture after one week. Therefore, H6H catalyzes two consecutive reactions that oxidize hyoscyamine to scopolamine.