Identification of a flavin-monooxygenase as the S-oxygenating enzyme in aliphatic glucosinolate biosynthesis in Arabidopsis
Identification of a flavin-monooxygenase as the S-oxygenating enzyme in aliphatic glucosinolate biosynthesis in Arabidopsis
复制标题
DOI：
10.1111/j.1365-313x.2007.03101.x
复制
发表时间：
2007-06-01
期刊：
影响因子：
7.2
通讯作者：
Halkier, Barbara A.
中科院分区：
文献类型：
--
作者：
Hansen, Bjarne G.;Kliebenstein, Daniel J.;Halkier, Barbara A.
十字花科蔬菜的防癌活性通常归因于由天然产物硫代葡萄糖苷（GSLs）分解产生的异硫氰酸盐。萝卜硫素是源自4 - 甲基亚磺酰基丁基GSL的异硫氰酸盐，被认为是赋予防癌特性的主要成分，而4 - 甲基硫代丁基GSL的异硫氰酸盐则不具有相同的活性。我们报道了一种拟南芥黄素单加氧酶（FMO），即FMOGS - OX1的鉴定，它催化甲硫烷基GSLs转化为甲基亚磺酰基烷基GSLs。这通过重组蛋白的生化特性以及对拟南芥FMOGS - OX1过表达株系和FMOGS - OX1敲除突变体中GSL含量的分析得以证明。FMOGS - OX1过表达株系显示甲硫烷基几乎完全转化为甲基亚磺酰基烷基GSLs，种子中4 - 甲基亚磺酰基丁基GSL增加了约五倍。FMOGS - OX1的鉴定为培育具有更高水平这种重要GSL的芸薹属蔬菜作物提供了一种分子工具，这对生产富含防癌萝卜硫素的功能性食品具有重要意义。
The cancer-preventive activity of cruciferous vegetables is commonly attributed to isothiocyanates resulting from the breakdown of the natural products glucosinolates (GSLs). Sulforaphane, the isothiocyanate derived from 4-methylsulfinylbutyl GSL, is thought to be the major agent conferring cancer-preventive properties, whereas the isothiocyanate of 4-methylthiobutyl GSL does not have the same activity. We report the identification of an Arabidopsis flavin-monooxygenase (FMO) enzyme, FMOGS-OX1, which catalyzes the conversion of methylthioalkyl GSLs into methylsulfinylalkyl GSLs. This is evidenced by biochemical characterization of the recombinant protein, and analyses of the GSL content in FMOGS-OX1 overexpression lines and an FMOGS-OX1 knock-out mutant of Arabidopsis. The FMOGS-OX1 overexpression lines show almost complete conversion of methylthioalkyl into methylsulfinylalkyl GSLs, with an approximately fivefold increase in 4-methylsulfinylbutyl GSL in seeds. Identification of FMOGS-OX1 provides a molecular tool for breeding of Brassica vegetable crops with increased levels of this important GSL, which has implications for production of functional foods enriched with the cancer-preventive sulforaphane.