Epithiospecifier protein from broccoli (Brassica oleracea L. ssp italica) inhibits formation of the anticancer agent sulforaphane
Epithiospecifier protein from broccoli (Brassica oleracea L. ssp italica) inhibits formation of the anticancer agent sulforaphane
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DOI：
10.1021/jf0525277
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发表时间：
2006-03-22
影响因子：
6.1
通讯作者：
Jeffery, EH
中科院分区：
文献类型：
--
作者：
Matusheski, NV;Swarup, R;Jeffery, EH
在某些十字花科植物中，表硫指定蛋白（ESP）指导黑芥子酶（EC 3.2-3.1）催化的烯基芥子油苷水解形成表硫腈。在这里，我们第一次表明，ESP活性是负相关的程度形成的健康促进植物化学物质萝卜硫素在花椰菜（甘蓝L。SSP.意大利）。从青花菜中克隆了一个具有ESP活性的43 kDa蛋白，该蛋白与拟南芥的ESP具有序列同源性。在大肠杆菌中表达。在一个模型系统中，重组蛋白不仅指导链烯基硫代葡萄糖苷表-前依春[（2S）-2-羟基-3-丁烯基硫代葡萄糖苷]的黑芥子酶依赖性代谢形成表硫腈，而且指导硫代葡萄糖苷硫代萝卜素[4-（甲基亚磺酰基）丁基硫代葡萄糖苷]的黑芥子酶依赖性水解形成萝卜硫素腈，代替异硫氰酸酯萝卜硫素。这一发现的重要性在于，虽然萝卜硫烷已被证明具有抗癌特性，但萝卜硫烷腈却没有。旨在减弱或消除西兰花中ESP表达的遗传操作可以增加萝卜硫素向萝卜硫素的转化率，从而增强潜在的健康益处。
In some cruciferous plants, epithiospecifier protein (ESP) directs myrosinase (EC 3.2-3.1)-catalyzed hydrolysis of alkenyl glucosinolates toward epithionitrile formation. Here, for the first time, we show that ESP activity is negatively correlated with the extent of formation of the health-promoting phytochemical sulforaphane in broccoli (Brassica oleracea L. ssp. italica). A 43 kDa protein with ESP activity and sequence homology to the ESP of Arabidopsis thaliana was cloned from the broccoli cv. Packman and expressed in Escherichia coli. In a model system, the recombinant protein not only directed myrosinase-dependent metabolism of the alkenyl glucosinolate epi-progoitrin [(2S)-2-hydroxy-3-butenyl glucosinolate] toward formation of an epithionitrile but also directed myrosinase-dependent hydrolysis of the glucosinolate glucoraphanin [4-(methylsulfinyl)butyl glucosinolate] to form sulforaphane nitrile, in place of the isothiocyanate sulforaphane. The importance of this finding is that, whereas sulforaphane has been shown to have anticarcinogenic properties, sulforaphane nitrile has not. Genetic manipulation designed to attenuate or eliminate expression of ESP in broccoli could increase the fractional conversion of glucoraphanin to sulforaphane, enhancing potential health benefits.