Department of Biological Sciences, Brock University, 500 Glenridge Ave, St. Catharines, ON, L2S 3A1, Canada.
Planta. 2011 Dec;234(6):1201-14. doi: 10.1007/s00425-011-1474-0. Epub 2011 Jul 14.
Grapes berries produce and accumulate many reactive secondary metabolites, and encounter a wide range of pathogen- and human-derived xenobiotic compounds. The enzymatic glucosylation of these metabolites changes their reactivity, stability and subcellular location. Two ESTs with more than 90% nucleotide sequence identity to three full-length glucosyltransferases are expressed in several grape tissues. The full-length clones have more than 60% amino acid sequence similarity to previously characterized flavonoid 7-O-glucosyltransferases, catechin O-glucosyltransferases and anthocyanin 5-O-glucosyltransferases. In vitro, these enzymes glucosylate flavonols and the xenobiotic 2,4,5-trichlorophenol (TCP). Kinetic analysis indicates that TCP is the preferred substrate for these enzymes, while expression analysis reveals variable transcription of these genes in grape leaves, flowers and berry tissues. The in vivo role of these Vitis labrusca glucosyltransferases is discussed.
葡萄浆果产生并积累了许多活性次生代谢物，并遇到了广泛的病原体和人类衍生的外来化合物。这些代谢物的酶葡糖苷化改变了它们的反应性、稳定性和亚细胞定位。在几种葡萄组织中表达了两个与三个全长葡糖基转移酶具有超过 90%核苷酸序列同一性的 EST。全长克隆与先前表征的类黄酮 7-O-葡糖基转移酶、儿茶素 O-葡糖基转移酶和花色苷 5-O-葡糖基转移酶具有超过 60%的氨基酸序列相似性。在体外，这些酶葡糖苷化黄酮醇和外来化合物 2,4,5-三氯苯酚 (TCP)。动力学分析表明，TCP 是这些酶的首选底物，而表达分析表明这些基因在葡萄叶、花和浆果组织中的转录存在差异。讨论了这些葡萄野生物种葡糖基转移酶的体内作用。
