Centre for Forest Biology and Department of Biology, University of Victoria, Victoria, BC, Canada.
Phytochemistry. 2013 Jul;91:148-57. doi: 10.1016/j.phytochem.2012.12.012. Epub 2013 Jan 30.
Two pathogen-induced uridine diphosphate glycosyltransferases (UGTs) identified previously via co-expression with induced proanthocyanidin (PA) synthesis in poplar were cloned and characterized. Phylogenetic analysis grouped both genes with other known flavonoid UGTs that act on flavonols and anthocyanins. Recombinant enzymes were produced in order to test if they could glycoslate flavonoids. PtUGT78L1 accepted the flavonols quercetin and kaempferol as well as cyanidin, and used UDP-galactose as a sugar donor. PtUGT78M1 did not accept any of the flavonoids tested as a substrate, but did transfer glucose from UDP-glucose to the universal substrate 2,4,6-trichlorophenol. However, neither enzyme acted on the flavan-3-ols catechin or epicatechin, intermediates in the PA biosynthetic pathway.
先前通过与杨树中诱导原花青素（PA）合成的共表达鉴定出两种病原体诱导的尿苷二磷酸糖基转移酶（UGTs），并对其进行了克隆和表征。系统发育分析将这两个基因与其他已知的黄酮类 UGT 聚类，这些酶作用于黄酮醇和花青素。为了测试它们是否能够糖基化黄酮类化合物，生产了重组酶。PtUGT78L1 接受了黄酮醇槲皮素和山柰酚以及飞燕草素，并使用 UDP-半乳糖作为糖供体。PtUGT78M1 不能接受任何测试的黄酮类化合物作为底物，但确实将葡萄糖从 UDP-葡萄糖转移到通用底物 2,4,6-三氯苯酚。然而，这两种酶都不能作用于黄烷-3-醇儿茶素或表儿茶素，这是 PA 生物合成途径的中间体。
