Substrate specificity of tuliposide-converting enzyme, a unique non-ester-hydrolyzing carboxylesterase in tulip: Effects of the alcohol moiety of substrate on the enzyme activity
作者:Yasuo Kato、Takashi Futanaga、Taiji Nomura
DOI:10.1016/j.bmcl.2018.12.010
日期:2019.2
carboxylesterase family, specifically catalyze intramolecular transesterification, but not hydrolysis. In this report, we synthesized analogues of Pos with various alcohol moieties, and measured the TgTCE activity together with a determination of the kinetic parameters for these analogues with a view to probe the substrate recognition mechanism of the unique non-ester-hydrolyzing TgTCEs. It was found
6-Tuliposides A(PosA)和B(PosB)是作为主要防御性次要代谢产物积聚在郁金香(Tulipa gesneriana)中的葡萄糖酯。我们先前从郁金香中发现的Pos转换酶(TgTCEs)分别催化PosA和PosB分别转化为抗菌性郁金香脂蛋白A(PaA)和B(PaB)的反应。属于羧酸酯酶家族的TgTCEs特异性催化分子内酯交换反应,但不催化水解。在本报告中,我们合成了具有各种醇基的Pos类似物,并测量了TgTCE活性,并确定了这些类似物的动力学参数,以期探索独特的非酯水解TgTCEs的底物识别机制。已经发现,d-葡萄糖样结构和醇部分中羟基的数目对于TgTCE识别底物很重要。在检测的类似物中,发现通过降低Km值,TgTCE比真实的底物更能特异性地识别PosA和PosB的1,2-二脱氧类似物。本结果将为设计用于TgTCE晶体学分析的简单,稳定的合成底物类似物提供基础。