- Bio-solvents change regioselectivity in the synthesis of disaccharides using Biolacta β-galactosidase
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Bio-solvents are good alternative solvents that avoid the use of classical organic solvents when performing enzymatic reactions. A noticeably change in regioselectivity was observed in the synthetic behaviour of Biolacta β-galactosidase using bio-solvents derived from dimethylamide and glycerol as co-solvents. Under these conditions, the enzyme changes its well known tendency to produce β-(1→4) to β-(1→6) disaccharides. An evaluation of the bio-solvent concentration and the effects of the non proteic additives in commercially available Biolacta β-galactosidase was undertaken in order to optimize the reaction conditions to improve the yield of the β-(1→6) product.
- Pérez-Sánchez, María,Sandoval, Manuel,Hernáiz, María J.
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experimental part
p. 2141 - 2145
(2012/03/27)
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- Regioselectivity in β-galactosidase-catalyzed transglycosylation for the enzymatic assembly of D-galactosyl-D-mannose
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The regioselectivity of β-galactosidase derived from Bacillus circulans ATCC 31382 (β-1,3-galactosidase) in transgalactosylation reactions using D-mannose as an acceptor was investigated. This D-mannose associated regioselectivity was found to be different from reactions using either GlcNAc or GalNAc as acceptors, not only for β-1,3-galactosidase but also for β-galactosidases of different origins. The relative hydrolysis rate of Galβ-pNP and D-galactosyl-D-mannoses, of various linkages, was also measured in the presence of β-1,3-galactosidase and was found to correlate well with the ratio of disaccharides formed by transglycosylation. The unexpected regioselectivity using D-mannose can therefore be explained by an anomalous specificity in the hydrolysis reaction. By utilizing the identified characteristics of both regioselectivity and hydrolysis specificity using D-mannose, an efficient method for enzymatic synthesis of β-1,3-, β-1,4- and β-1,6-linked D-galactosyl-D-mannose was subsequently established.
- Miyasato, Mariko,Ajisaka, Katsumi
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p. 2086 - 2090
(2007/10/03)
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- NMR assignments for glucosylated and galactosylated N- acetylhexosaminitols: Oligosaccharide alditols related to O-linked glycans from the protozoan parasite Trypanosoma cruzi
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We report full 1H and 13C NMR assignments for 13 gluco- or galacto- pyranosylated derivatives of GlcNAc-ol, GalNAc-ol or ManNAc-ol, many of which have been prepared by enzymatic methods. These spectra are reference data to aid the structural analysis by NMR spectroscopy of glycosylated alditols derived from the mucin of the protozoan parasite Trypanosoma cruzi. A series of structural reporter groups for the derivatives from this unusual series of O-glycans are described. (C) 2000 Elsevier Science Ltd.
- Jones, Christopher,Previato, Jose O.,Mendonca-Previato
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p. 321 - 330
(2007/10/03)
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