13299-16-6Relevant articles and documents
Glycon specificity profiling of α-glucosidases using monodeoxy and mono-O-methyl derivatives of p-nitrophenyl α-D-glucopyranoside
Nishio, Toshiyuki,Hakamata, Wataru,Kimura, Atsuo,Chiba, Seiya,Takatsuki, Akira,Kawachi, Ryu,Oku, Tadatake
, p. 629 - 634 (2007/10/03)
Hydrolysis of probe substrates, eight possible monodeoxy and mono-O-methyl analogs of p-nitrophenyl α-D-glucopyranoside (pNP α-D-Glc), modified at the C-2, C-3, C-4, and C-6 positions, was studied as part of investigations into the glycon specificities of seven α-glucosidases (EC 3.2.1.20) isolated from Saccharomyces cerevisiae, Bacillus stearothermophilus, honeybee (two enzymes), sugar beet, flint corn, and Aspergillus niger. The glucosidases from sugar beet, flint corn, and A. niger were found to hydrolyze the 2-deoxy analogs with substantially higher activities than against pNP α-D-Glc. Moreover, the flint corn and A. niger enzymes showed hydrolyzing activities, although low, for the 3-deoxy analog. The other four α-glucosidases did not exhibit any activities for either the 2- or the 3-deoxy analogs. None of the seven enzymes exhibited any activities toward the 4-deoxy, 6-deoxy, or any of the methoxy analogs. The hydrolysis results, with the deoxy substrate analogs, demonstrated that α-glucosidases having remarkably different glycon specificities exist in nature. Further insight into the hydrolysis of deoxyglycosides was obtained by determining the kinetic parameters (kcat and Km) for the reactions of sugar beet, flint corn, and A. niger enzymes.
Hydrolytic activity of α-galactosidases against deoxy derivatives of p- nitrophenyl α-D-galactopyranoside
Hakamata, Wataru,Nishio, Toshiyuki,Oku, Tadatake
, p. 107 - 115 (2007/10/03)
The four possible monodeoxy derivatives of p-nitrophenyl (PNP) α-D- galactopyranoside were synthesized, and hydrolytic activities of the α- galactosidase of green coffee bean, Mortierella vinacea and Aspergillus niger against them were elucidated. The 2- and 6-deoxy substrates were hydrolyzed by the enzymes from green coffee bean and M. vinacea, while they scarcely acted on the 3- and 4-deoxy compounds. On the other hand, A. niger α- galactosidase hydrolyzed only the 2-deoxy compound in these deoxy substrates, and the activity was very high. These results indicate that the presence of two hydroxyl groups (OH-3 and -4) is essential for the compounds to act as substrates for the enzymes of green coffee bean and M. vinacea, while the three hydroxyl groups (OH-3, -4, and -6) are necessary for the activity of the A. niger enzyme. The kinetic parameters (K(m) and V(max)) of the enzymes for the hydrolysis of PNP α-D-galactopyranoside and its deoxy derivatives were obtained from kinetic studies. (C) 2000 Elsevier Science Ltd.
Hydrolysis of (2-deoxy-α-D-glucopyranosyl)pyridinium salts: The 2- deoxyglucosyl oxocarbenium is not solvent-equilibrated in water
Zhu, Jiang,Bennet, Andrew J.
, p. 3887 - 3893 (2007/10/03)
The hydrolysis reactions of four 2-deoxy-α-D-glucopyranosyl pyridinium salts exhibit first-order rate constants that are independent of pH in the range of 4.4-10.5 pH units. Derived second-order rate constants for the hydrolysis reactions of 2-deoxy-α-D-glucopyranosyl 4'-bromoisoquinolinium tetrafluoroborate (4d) conducted in the presence of nucleophilic monoanions (u = 2.0) including AcO-, Cl-, Br-, and N3/- exhibit a Swain-Scott parameter (s) of 0.03 ± 0.10, indicating that these reactions show no sensitivity to the nature of the anion. In the presence of azide ion, a substantial quantity of the 2-deoxy-α-glucopyranosyl 4'-bromoisoquinolinium salt hydrolysis product results from a post rate-limiting reaction of a cationic intermediate with azide. Analysis of the hydrolysis product ratios indicates that the 2-deoxyglucosyl oxocarbenium ion is not solvent- equilibrated in water. Furthermore, the reaction of solvent occurs about 2- fold faster with the cationic intermediate that is formed during solvolysis of the β-anomeric salt than with the corresponding intermediate produced from the reactions of the α-anomer 4d.
