Glycosidase-catalysed synthesis of glycosides by an improved procedure for reverse hydrolysis: application to the chemoenzymatic synthesis of galactopyranosyl-(1→4)- O-α-galactopyranoside derivatives (original) (raw)
Journal of Biotechnology, 1999
Enzymatic synthesis of butylgalactoside via the transglycosylation reaction of lactose was carried out using b-galactosidase from Aspergillus oryzae. Reactions were performed in monophasic (butanol phase) and biphasic systems (emulsified aqueous in butanol phase). The results indicated that water content was an essential parameter of this reaction. In the case of the monophasic system, addition of water led to a significant increase of product concentration. The highest concentration was obtained at 17% (v/v) of water. Conversely, in the case of the biphasic system, increasing the aqueous/butanol phase ratio (v/v) provoked a decrease of the final butylgalactoside concentration. In this system, the reaction performance was lower than that in the monophasic system. Lactose favorably influenced the reaction synthesis. However, at high concentrations, it led to a drastic decrease of the product concentration.
New enzyme catalyzed synthesis of monoacyl galactoglycerides
Tetrahedron, 1988
l-Acyl-3-0-S-D-galactopyranosylglycerides have been prepared by S-galactosidase catalysed trans-galactosidation of lactose (1) or o-nitrophenyl galactopyranoside(4) with 2,3-epoxypropanol (2) and subsequent opening of the so formed 1-O-S-D-galactopyranosyl-2,3-epoxypropanol (3_) with a fatty acid. Usually, selective modification and derivatisation of sugars require extensive application of protection and deprotection procedures (1). Accordingly, large scale preparation of many interesting and potentially useful sugar derivatives as well as detailed studies of such compounds may be quite troublesome. Moreover the
Chemical and enzymatic synthesis of glycoconjugates 1. Enzymatic galactosylation of conduritol B
Tetrahedron Letters, 1995
&Galactosidmeactivitiesfromthe recombinanttbermophilicCLONEZYMEmglycosidase librarywers screenedat70"C for catalysisof atrarrsgalactosylation &omo-nitrophenyl$galactopyranosideto N-aeetylglucosamine.Threethermophilicglycosidases(GlyOO1-06, -07 and -09) were foundto producepredominantlythe~(1-4)-linkedisomer,Gal~(1-4)GlcNAcwith up to 610/0 yield and less than 10Yo of the hydrolysisside reactionproduct. Thus, commercialrecombinantthermophilic enzymelibrariesconstitutea novelclass of biocatalystsfor preparativeorganicsynthesis. 01997 Elsevier Science Ltd.
Bioorganic & Medicinal Chemistry Letters, 2005
The use of crude extract of the hepatopancreas of Aplysia fasciata, a large mollusc belonging to the order Anaspidea containing a b-galactosidase activity, was reported for the synthesis of different galactosides. Good yields with polar acceptors and the uncommon b-1-3 selectivity in the transgalactosylation reactions with most of the acceptors were observed. A b-1-2 selectivity in the hydrolytic conditions was also observed and discussed.
Synthesis of β-mercaptoethyl-glycosides by enzymatic reverse hydrolysis and transglycosylation
Biotechnology Letters, 1994
The synthetic potential of Almond eglucosidase and Jack bean a-mannosidase in the presence of high amounts of &mercaptoethanol as glycosyl acceptor for the synthesis of @mercaptoethyl-glycosides was studied. The regioselectivity, 0-glycosylation and/or Sglycosylation, and the stereoselectivity were analyzed with the reverse hydrolysis and the transglycosylation methods. With both enzymes, high yields of condensation are obtained without the use of chemical protective groups.
Recent biotechnological progress in enzymatic synthesis of glycosides
Journal of Industrial Microbiology & Biotechnology, 2013
Glycosylation is one of the most important post-modification processes of small molecules and enables the parent molecule to have increased solubility, stability, and bioactivity. Enzyme-based glycosylation has achieved significant progress due to advances in protein engineering, DNA recombinant techniques, exploitation of biosynthetic gene clusters of natural products, and computer-based modeling programs. Our report summarizes glycosylation data that have been published within the past five years to provide an overall review of current progress. We also present the future trends and perspectives for glycosylation.
Journal of Agricultural and Food Chemistry, 2009
The synthesis of novel galactosides is interesting because of their important role in several biological processes. Their properties greatly depend upon the configuration and type of galactoside. Therefore, to study biological activity, it is essential to elucidate the structure of the products. Glycosidases are capable of catalyzing glycosidic linkages with absolute stereoselectivity of the anomeric center. We report the enzymatic synthesis of galactosyl-ethylene glycol, galactosylglycerol, and galactosyl-erythritol by immobilized β-galactosidase from Aspegillus oryzae. The obtained galactosides were isolated and fully characterized by an extensive nuclear magnetic resonance (NMR) study. Complete structure elucidation and full proton and carbon assignments were carried out using 1D (1 H and 13 C) and 2D (gCOSY, TOCSY, multiplicity-edited gHSQC, and gHMBC) NMR experiments. The β-galactosidase from A. oryzae showed a strong preference for primary alcohols. For galactosyl-glycerol and galactosyl-erythritol, this preference generated one and two chiral centers, respectively, and a mixture of stereoisomers was obtained as a consequence.
Recent Developments in Glycoside Synthesis with Glycosynthases and Thioglycoligases
Australian Journal of Chemistry, 2009
Glycosynthases are hydrolytically incompetent engineered glycosidases that catalyze the high-yielding synthesis of glycoconjugates from glycosyl fluoride donor substrates and appropriate acceptors. Glycosynthases from more than 10 glycoside hydrolase families have now been generated, allowing the synthesis of a wide range of oligosaccharides. Recent examples include glycosynthase-mediated syntheses of xylo-oligosaccharides, xyloglucans, glycolipids, and aryl glycosides. Glycosynthases have also now been generated from inverting glycosidases, increasing the range of enzyme scaffolds. Improvement of glycosynthase activity and broadening of specificity has been achieved through directed evolution approaches, and several novel high-throughput screens have been developed to allow this. Finally, metabolically stable glycoside analogues have been generated using another class of mutant glycosidases: thioglycoligases. Recent developments in all these aspects are discussed.