Small-molecule glucosylation by sucrose phosphorylase: structure–activity relationships for acceptor substrates revisited
摘要:
Sucrose phosphorylase catalyzes the O-glucosylation of a wide range of acceptor substrates. Acceptors presenting a suitable 1,2-diol moiety are glucosylated exclusively at the secondary hydroxyl. Production of the naturally occurring compatible solute, 2-O-alpha-D-glucopyranosyl-sn-glycerol, from sucrose and glycerol is a notable industrial realization of the regio- and stereoselective biotransformation promoted by sucrose phosphorylase. The acceptor substrate specificity of sucrose phosphorylase was analyzed on the basis of recent high-resolution crystal structures of the enzyme. Interactions at the acceptor binding site, observed in the crystal (D-fructosyl) and suggested by results of docking experiments (glycerol), are used to rationalize experimentally determined efficiencies and regioselectivities of enzymatic glucosyl transfer. (c) 2010 Elsevier Ltd. All rights reserved.
[EN] PREPARATION OF TRISACCHARIDES (KESTOSES) AND POLYMERS BY PYROLYSIS OF AMORPHOUS SUCROSE
申请人:——
公开号:WO1993007159A1
公开(公告)日:1993-04-15
[FR] On traite le saccharose avec un catalyseur acide pour former un produit de fusion anhydre de saccharose amorphe. En chauffant ce produit de fusion anhydre à 80-100 °C, on forme trois kestoses connus et aussi des produits nouveaux, à savoir des anomères d'alpha-fructosylsaccharose de 6-kestose, du néo-kestose et du 1-kestose. En chauffant le produit de fusion anhydre à 125-175 °C, on forme un polymère de saccharose fructoglucane doté d'un poids moléculaire d'environ 2000 à 10000 Daltons. Tous ces produits sont utiles comme édulcorants, additifs alimentaires, y compris pour nourritures animales, et agents de gonflement. [EN] Sucrose is treated with an acid catalyst to form an amorphous sucrose anhydrous melt. Heating of the anhydrous melt at 80-100 C forms three known kestoses and the novel products, viz. $g(a)-fructosylsucrose anomers of 6-kestose, neokestose, and 1-kestose. Heating of the anhydrous melt at 125-175 C produces a fructoglucan sucrose polymer having a molecular weight of about 2,000 to 10,000 Daltons. All of these products are useful as sweeteners, food additives, additives for animal food, and bulking agents.
Catalytic dehydration of fructose to 5-hydroxymethylfurfural over a mesoscopically assembled sulfated zirconia nanoparticle catalyst in organic solvent
With MASZN-3 as catalyst, a HMF yield of 91.9% with a 98.5% fructose conversion was obtained at 110 °C for 120 min in DMSO. Finally, the catalyst MASZN-3 was recycled in four consecutive cycles with scarcely any loss of activity. The excellent catalytic properties together with its easy synthesis, low cost, and nontoxic nature make this MASZN a promisingcatalyst for the development of new and efficient