61-58-5Relevant academic research and scientific papers
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.
Glycosidase-catalyzed hydrolysis of 2-deoxyglucopyranosyl pyridinium salts: Effect of the 2-OH group on binding and catalysis
Tanaka, Kelly S. E.,Zhu, Jiang,Huang, Xicai,Lipari, Francesco,Bennet, Andrew J.
, p. 577 - 582 (2007/10/03)
Three 2-deoxy-α-D-glucopyranosyl pyridinium tetrafluoroborates were tested for their binding affinity to a range of α-glucosidases and α-mannosidases. The α- isoquinolinium salt (11) binds approximately 275-fold more tightly to yeast α-glucosidase than does the isomeric quinolinium salt (12). In addition, compound 11 binds to the yeast enzyme approximately two-fold tighter than the corresponding glucopyranosyl isoquinolinium salt (9). The (k(cat)/k(hyd)) values for the yeast α-glucosidase-catalyzed reactions of 11 and 9 are 1.6 x 105 and 2.0 x 109, respectively, when compared to the spontaneous uncatalyzed reactions. Thus, the interaction of the 2-OH group in compound 9 with the yeast enzyme's active site generates a relative transition state stabilization of about 23.5 kJ mol-1. For both compounds 11 and 12, the observed rate accelerations for the yeast α-glucosidase-catalyzed hydrolysis, relative to the spontaneous reaction in solution, (k(cat)/k(hyd) are identical within experimental error.
Specificity of amylases and cyclodextrin-glucanotransferase in reactions with 2-deoxy-maltooligosaccharides
Evers, Britta,Petricek, Miroslav,Thiem, Joachim
, p. 153 - 159 (2007/10/03)
2-Deoxy-maltooligosaccharides of different chain length were tested as substrates for exo- and endo-amylases. Cleavage occurred with β-amylase, yielding 2,2'-dideoxy-maltose, and with amyloglucosidase. With the α-amylase from Thermomonospora curvata tris-(2-deoxy)-maltotriose and the corresponding tetra- and pentasaccharides were formed. Porcine pancreatic α-amylase did not tolerate the deoxygenated substrate, nor were cyclization experiments with cyclodextrin-glucanotransferase (CGT) successful. In a coupling reaction with CGT, however, a series of transfer products to the acceptor 2-deoxyglucose were obtained.
Hydrolysis of (2-deoxy-β-D-glucopyranosyl)pyridinium salts
Huang, Xicai,Surry, Clint,Hiebert, Timothy,Bennet, Andrew J.
, p. 10614 - 10621 (2007/10/03)
The hydrolysis reactions of three (2-deoxy-β-D-glucopyranosyl)pyridinium salts exhibit first-order rate constants that are independent of pH in the range of 4.4-10.1 pH units. Derived second-order rate constants for the hydrolysis reactions of (2-deoxy-β-D-glucopyranosyl)-4′-bromoisoquinolinium bromide (5b) conducted in the presence of nucleophilic monoanions (μ = 2.0) including AcO-, Cl-, Br-, and N3 exhibit a Swain-Scott parameter (s) of 0,03 ± 0.05, indicating that these reactions show no sensitivity to the nature of the anion. However, a substantial quantity of the (2-deoxyglucopyranosyl)pyridinium salt hydrolysis product is formed as a result of a post-rate-limiting reaction involving a nucleophilic anion. Analysis of the product ratios indicates that the first-formed intermediate in the hydrolytic reaction is a solvent-separated ion painmolecule encounter complex. The data allow a calculated estimate of greater than 2.5 × 10-12 s for the lifetime of the glucopyranosyloxocarbenium ion in aqueous solution.
