Over the past decade, disaccharide phosphorylases have received increasing attention as promising biocatalysts for glycoside synthesis. Unfortunately, these enzymes typically have a very low affinity for non-carbohydrate acceptors, which urges the addition of cosolvents to increase the dissolved concentration of these acceptors. However, commonly applied solvents such as methanol and dimethyl sulfoxide (DMSO) are not compatible with many intended applications of carbohydrate-derived products. In this work, the solubility of a wide range of relevant acceptors was assessed in the presence of ionic liquids (ILs) as alternative and ‘green’ solvents. The IL AMMOENG 101 was found to be the most effective cosolvent for compounds as diverse as medium- and long-chain alcohols, flavonoids, alkaloids, phenolics and terpenes. Moreover, this IL was shown to be less deleterious to the stability and activity of sucrose phosphorylase than the commonly used dimethyl sulfoxide. To demonstrate the usefulness of this solvent system, a process for the resveratrol glycosylation was established in a buffer containing 20% AMMOENG 101, 1 M sucrose and saturated amounts of the acceptor. A single regioisomer 3-O-α-D-glucopyranosyl-(E)-resveratrol was obtained as proven by NMR spectroscopy.
在过去的十年中,二糖
磷酸化酶作为一种有前途的糖苷合成
生物催化剂,受到了越来越多的关注。遗憾的是,这些酶对非
碳水化合物受体的亲和力通常很低,因此需要添加助溶剂来增加这些受体的溶解浓度。然而,
甲醇和
二甲基亚砜(
DMSO)等常用溶剂与
碳水化合物衍生产品的许多预期应用不兼容。在这项工作中,我们评估了多种相关受体在
离子液体(IL)作为替代和 "绿色 "溶剂存在时的溶解度。研究发现,
离子液体 AMMOENG 101 是中长链醇、类
黄酮、
生物碱、
酚类和
萜类等多种化合物最有效的共溶剂。此外,与常用的
二甲亚砜相比,这种 IL 对
蔗糖磷酸化酶的稳定性和活性的影响较小。为了证明这种溶剂系统的实用性,我们在含有 20%
AMMOENG 101、1 M
蔗糖和饱和量受体的缓冲液中建立了
白藜芦醇糖基化过程。核磁共振光谱证明,得到了单一的 3-O-α-
D-吡喃葡萄糖基-(E)-
白藜芦醇异构体。