锤子
消耗积分 : 免积分
Previously it has been shown that glycerol can be regioselectively glucosylated by sucrose phosphorylase from Leuconostoc mesenteroides to form 2-O--d-glucopyranosyl glycerol.A series of compounds related to glycerol were investigated by us to determine the scope of the -glucosylation reaction of sucrose phosphorylase. Both sucrose and glucose 1-phosphate (G1P) were applied as glucosyl donor. Mono-alcohols were not accepted as substrates but several 1,2-diols were readily glucosylated, proving that the vicinal diol unit is crucial for activity. The smallest substrate that was accepted for glucosylation appeared to be ethylene glycol,which was converted to the monoglucoside for 69%. Using high acceptor and donor concentrations (up to 2.5 M), sucrose or G1P hydrolysis (with H2O being the ‘acceptor’) can be minimised. In the study cited above, a preference for glucosylation of glycerol on the 2-position has been observed. For 1,2-propanediol however, the regiochemistry appeared to be dependent on the configuration of the substrate. The (R)-enantiomer was preferentialy glucosylated on its 1-position (ratio 2.5:1), whereas the 2-glucoside is the major product for (S)-1,2-propanediol (1:4.1). d.e.ps of 71–83% were observed with a preference for the (S)-enantiomer of the glucosides of 1,2-propanediol and 1,2-butanediol and the (R)-enantiomer of the glucoside of 3-methoxy-1,2-propanediol. This is the first example of stereoselective glucosylation of a non-natural substrate by sucrose phosphorylase. 3-Amino-1,2-propanediol, 3-chloro-1,2-propanediol, 1-thioglycerol and glyceraldehyde were not accepted as substrates.
打开失败或需在电脑查看,请在电脑上的资料中心栏目,点击"我的下载"。建议使用手机自带浏览器。