Liu Tao, Zhu Ping, Cheng Ke-di, Meng Chao, He Hui-Xia
Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, #1 Xian Nong Tan Street, Beijing 100050, P. R. China.
Planta Med. 2005 Mar;71(3):249-53. doi: 10.1055/s-2005-837825.
Anisodus tanguticus, one of the indigenous Chinese ethnological medicinal plants of the Solanaceae, produces anticholinergic alkaloids such as hyoscyamine, 6 beta-hydroxyhyoscyamine and scopolamine. Hyoscyamine 6 beta-hydroxylase (H6H), a key enzyme in the biosynthetic pathway of scopolamine, catalyzes the hydroxylation of hyoscyamine and epoxide formation from 6 beta-hydroxyhyoscyamine to generate scopolamine. A full-length cDNA of H6H has been isolated from A. tanguticus hairy roots. Nucleotide sequence analysis of the cloned cDNA revealed an open reading frame of 1035 bp encoding 344 amino acids with high homology to other known H6Hs. The equivalent amino acid sequence shows a typical motif of 2-oxoglutarate-dependent dioxygenase. The A. tanguticus H6H was expressed in Escherichia coli and purified for enzyme function analysis. This study characterized the recombinant AtH6H and showed it could generate scopolamine from hyoscyamine.
唐古特马尿泡是中国茄科本土民族药用植物之一，能产生抗胆碱生物碱，如莨菪碱、6β-羟基莨菪碱和东莨菪碱。莨菪碱6β-羟化酶（H6H）是东莨菪碱生物合成途径中的关键酶，催化莨菪碱的羟基化反应以及6β-羟基莨菪碱形成环氧化物以生成东莨菪碱。已从唐古特马尿泡毛状根中分离出H6H的全长cDNA。对克隆的cDNA进行核苷酸序列分析，发现一个1035 bp的开放阅读框，编码344个氨基酸，与其他已知的H6H具有高度同源性。对应的氨基酸序列显示出2-氧代戊二酸依赖性双加氧酶的典型基序。唐古特马尿泡H6H在大肠杆菌中表达并纯化以进行酶功能分析。本研究对重组AtH6H进行了表征，并表明它可以从莨菪碱生成东莨菪碱。
