P-Cellobioside

Lipkind et al. [85, 90] used their above mentioned procedure to calculate the conformations of methyl-P-cellobioside conformations with (p/ f of 30°/—40° (39%), 55°/20° (38%), -20°/-25° (10%), and 30°/175° (13%). They support their calculations with the 3Jch coupling constants across the glycosidic bond. Although these authors use a torsional potential around the glycosidic Cl-Ol bond, they assume that the exo anomeric effect does not exist. This was later criticized by Lemieux et al. [72] (cf. below). 

An al,6-linked trisaccharide unit of xylogucan resulted in 15% yield when a-xylosyl fluoride was used as a glycosyl donor and /iNP-P-cellobioside was used as an acceptor. 

To check for potential contamination with wt Cel7A in the mutant enzyme preparations, the irreversible inhibition of these enzymes with (R,S)-3,4-epoxybutyl P-cellobioside (G2-O-C4) was followed in function of time (28). A solution of 90 pM Cel7A wt and 180 pM E212Q, D214N and E217Q in 10 mM acetate buffer (pH 5.0) was added to 0.5 mM G2-O-C4 in the same buffer. The reaction was incubated at room temperature during nine hours. At different time intervals, aliquots were withdrawn to measure the residual activity on 4 mM CNPLac in 50 mM phospate buffer, pH 5.7 following the procedure described above. 

Given the similarity of the Km values measured for the mutants to those of the wild-type enzyme, it was necessary to further investigate the possibility that residual activity of the active-site mutants arises from traces of wild-type enzyme, either by contamination during the purification process, by spontaneous deamidation or translational misreading (31, 32). Active site titration with the mechanism-based inactivator 2,4-dinitrophenyl-2-deoxy-2-fluoro P-cellobioside... 

The following disaccharides and derivatives have been subjected to conformational analysis by n.m.r spectroscopy and/or computational methods cellobiose in aqueous solution, methyl P-xylobioside, methyl P-cellobioside, P-gentibiose, all possible monomethyl ethers of methyl p-lactoside, unsaturated, sulfated disaccharides, such as IS, obtained by cleavage of glycosaminoglycans with lyases, ° chondroitin sulfate-related ctmqmunds, such as 16, the uronic... 

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