title: Comparative study of new alpha-galactosidases in transglycosylation reactions.
abstract: We have studied the potential of several newly cloned alpha-galactosidases to catalyze the regioselective synthesis of disaccharides using 4-nitrophenylgalactoside as a donor. The kinetics of the reactions were followed by in situ NMR spectroscopy. The following thermophilic enzymes have been tested: Aga A and an isoenzyme Aga B obtained from the strain KVE39 and Aga 285 from the strain IT285 of Bacillus stearothermophilus; Aga T is an alpha-galactosidase from Thermus brockianus (strain IT360). Two other non-thermophilic alpha-galactosidases have also been evaluated: Aga 1 (Streptococcus mutans, strain Ingbritt) and Raf A (Escherichia coli, strain D1021). For all of the enzymes studied, high regioselectivity was observed leading to two (1 --> 6)-disaccharides: 4-nitrophenyl alpha-D-galactopyranosyl-(1--> 6)-alpha-D-galactopyranoside and methyl alpha-D-galactopyranosyl-(1--> 6)-alpha-D-galactopyranoside, which were obtained in 54% (Aga B) and 20% (Aga T) yields, respectively.
authors.affiliation: Unité de Recherches en Biocatalyse (Unité CNRS 2230), Faculte des Sciences et des Techniques, Nantes, France.
authors.forename: P
authors.initials: P
authors.lastname: Spangenberg
authors.forename: C
authors.initials: C
authors.lastname: André
authors.forename: M
authors.initials: M
authors.lastname: Dion
authors.forename: C
authors.initials: C
authors.lastname: Rabiller
authors.forename: R
authors.initials: R
authors.lastname: Mattes
mesh_terms: D002384:Catalysis; D003001:Cloning, Molecular; D004187:Disaccharides / Q000138:chemical synthesis* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D001411:Geobacillus stearothermophilus / Q000201:enzymology; D006031:Glycosylation; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009598:Nitrophenylgalactosides / Q000737:chemistry / Q000378:metabolism; D013295:Streptococcus mutans / Q000201:enzymology; D013824:Thermus / Q000201:enzymology; D000519:alpha-Galactosidase / Q000378:metabolism*
chemical_list: D004187:Disaccharides; D009598:Nitrophenylgalactosides; C059200:4-nitrophenylgalactoside; D000519:alpha-Galactosidase