Carbohydrates are important lead compounds in drug discovery and disease curing.Chemical synthesis of carbohydrates has long steps and low yield,so more and more attention was devoted to enzymatic synthesis which has simple reaction.Enzymatic synthesis of carbohydrates was mainly catalyzed by glycosyltransferases(GT)and Leloir stype GT are mainly used,sugar donor subtrates are sugar-nucleotides.Consequently,the preparation of sugar-nucleotides is very important for the enzymatic synthesis of bioactive oligosaccharides [1].Recently,we found that NahK_15697 could phosphorylate a number of monosaccharides including mannose and derivatives.Taking advantage of this and the promiscuity of NahK_15697 and a GDP-Man pyrophosphorylase from Pyrococcus furiosus DSM3638(PFManC),we present an efficient one-pot three enzyme system for quick preparative-scale synthesis of GDP-sugars [2].In order to provide more substrates for the study of glycosyltransferase,we synthesized here 14 analogs of mannose(Fig.1)to produce more non-natural sugar-nucleotide donors.