Enzymic .beta.-Galactosidation of Modified Monosaccharides: Study of the Enzyme Selectivity for the Acceptor and Its Application to the Synthesis of Disaccharides
作者:Rosa Lopez、Alfonso Fernandez-Mayoralas
DOI:10.1021/jo00083a013
日期:1994.2
The selectivity of the E. coli beta-galactosidase-catalyzed glycosylation of monosaccharides differently substituted at the anomeric position has been studied. Substituents bearing a phenyl ring increase the enzyme-acceptor binding; however, partial enzyme inhibition occurs. The regioselectivity of the glycosylation was dependent on small variations in the monosaccharide accceptor, such as the atom linked to the anomeric carbon and the number of methylenes between this atom and aromatic ring. A schematic model is proposed that accounts for the results. The information from this study allows the direct synthesis of disaccharides, with high regioselectivity and yields ranging from 30 to 40%.
Enzymatic syntheses and selective hydrolysis of O-β-d-galactopyranosides using a marine mollusc β-galactosidase
The use of crude extract of the hepatopancreas of Aplysia fasciata, a large mollusc belonging to the order Anaspidea containing a beta-galactosidase activity, was reported for the synthesis of different galactosides. Good yields with polar acceptors and the uncommon beta-1-3 selectivity in the transgalactosylation reactions with most of the acceptors were observed. A beta-1-2 selectivity in the hydrolytic conditions was also observed and discussed. (C) 2004 Elsevier Ltd. All rights reserved.
Controlling yield and regioselectivity in the enzymatic synthesis of β-D-galactopyranosyl-β-D-xylopyranosides
作者:Rosa López、Alfonso Fernández-Mayoralas
DOI:10.1016/s0040-4039(00)79118-0
日期:1992.9
Yield and regioselectivity of the galactosidation of beta-D-xylopyranosides catalysed by the beta-galactosidase from E. coli can be modulated by the nature of the aglyconic moiety of the xylopyranosides.
Optimizing the enzymatic synthesis of β-d-galactopyranosyl-d-xyloses for their use in the evaluation of lactase activity in vivo
作者:Carmen Hermida、Guillermo Corrales、Francisco J. Cañada、Juan J. Aragón、Alfonso Fernández-Mayoralas
DOI:10.1016/j.bmc.2007.04.067
日期:2007.7
their use in the evaluation of intestinallactase activity in vivo. Their administration to suckling rats followed by determination of the derived D-xylose in the urine and measurement of lactase activity in intestinal homogenates showed 1 to be the most suitable disaccharide for a potential test of the deficiency of intestinallactase. The synthesis of 1 was further studied by evaluating the effect of