87982-94-3Relevant academic research and scientific papers
Optimised N-acetyl-D-lactosamine synthesis using Thermus thermophilus β-galactosidase in bio-solvents
Sandoval, Manuel,Civera, Concepción,Berenguer, José,García-Blanco, Francisco,Hernaiz, María J.
, p. 1148 - 1152 (2013)
Synthesis of N-acetyl-D-lactosamine (Gal-β[1→4]GlcNAc, LacNAc) catalyzed by β-galactosidase from Thermus thermophilus (TTP0042) is affected by side reactions that give as result very low yields (about 20%) of LAcNAc when the reaction is performed in buffer. The process is improved (up to 91% of disaccharide yield) when the reaction takes place in the presence of solvents from biomass (bio-solvents) at 2.0 M concentration. Most of the solvents tested increased the LacNAc synthesis and reduced the undesired side reactions. In order to understand the possible effects of these solvents over the enzyme regioselectivity, we developed a conformational study of the enzyme structure in the presence of a selected bio-solvent by circular dichroism and fluorescence. According to this study, we were able to conclude that the presence of bio-solvents in the reaction media modifies the enzyme secondary and tertiary structure and this may be the cause of the regioselectivity changes observed in the transglycosylation reaction.
On the effect of the aglycon structure of three aryl β-D-galactosides on the yield and the regioselecttvity of the transglycolytic synthesis of N-acetyllactosamine
Vetere, Amedeo,Novelli, Lara,Paoletti, Sergio
, p. 515 - 521 (2007/10/03)
We examined the effect as donors of three aryl β-D-galactosides (i.e. p-nitrophenyl β-D-galactopyranoside, o-nitrophenyl β-D-galactopyranoside and phenyl β-D-galactopyranoside) on the regioselectivity and the yield of the synthesis of N-acetyllactosamine obtained from the transglycosylation reaction catalyzed by a crude preparation of β-D-galactosidase from Bacillus circulans at 25°C, 37°C and 55°C, respectively. Using p-nitrophenyl β-D-galactopyranoside the reaction results were fully regiospecific at all the temperatures considered: the maximum molar yield (74%) was obtained at an incubation temperature of 55°C Using o-nitrophenyl β-D-galactopyranoside as the donor the reaction was still highly regioselective and the maximum molar yield (50%) was achieved at an incubation temperature also of 55°C. Using phenyl β-D-galactopyranoside transglycolytic products appear only at an incubation temperature of 55°C but at very low molar yield (about 14%) and lower regioselectivity.
Chemical and enzymatic synthesis of glycoconjugates 2. High yielding regioselective synthesis of N-acetyllactosamine by use of recombinant thermophilic glycosidases library
Li, Jun,Wang, Peng G.
, p. 7967 - 7970 (2007/10/03)
β-Galactosidase activities from the recombinant thermophilic CLONEZYME(TM) glycosidase library were screened at 70°C for catalysis of a transgalactosylation from o-nitrophenyl-β-galactopyranoside to N-acetylglucosamine. Three thermophilic glycosidases (Gly001-06, -07 and -09) were found to produce predominantly the β(1-4)-linked isomer, Gal β(1-4)GlcNAc with up to 61% yield and less than 10% of the hydrolysis side reaction product. Thus, commercial recombinant thermophilic enzyme libraries constitute a novel class of biocatalysts for preparative organic synthesis.
ENZYMIC SYNTHESIS OF DISACCHARIDES BY USE OF THE REVERSED HYDROLYSIS ACTIVITY OF β-D-GALACTOSIDASES
Ajisaka, Katsumi,Fujimoto, Hiroshi,Nishida, Hiroko
, p. 35 - 42 (2007/10/02)
D-Galactosyl disaccharides have been synthesized by utilizing the reversed hydrolysis activity of β-D-galactosidases from E. coli and from A. oryzae, respectively.In order to shift the equilibrium towards the formation of disaccharide, solutions of monosaccharides were circulated through columns of immobilized β-D-galactosidase and activated carbon in series.After 24 h, the disaccharides were eluted with aqueous 50 percent ethanol from the column of activated carbon and analyzed by h.p.l.c. and 13C-n.m.r. spectroscopy.In this way, β-D-galactosyl-D-glucose, β-D-galactosyl-2-acetamido-2-deoxy-D-glucose, and β-D-galactosyl-D-fructose were produced in yields of 6.0, 16.0, and 11.3 percent, respectively, when the immobilized β-D-galactosidase from E. coli was used.The possible mechanism of the synthesis of the disaccharides is discussed.
