1854-25-7Relevant academic research and scientific papers
Thermostable variants of pyranose 2-oxidase showing altered substrate selectivity for glucose and galactose
Spadiut, Oliver,Nguyen, Tien-Thanh,Haltrich, Dietmar
, p. 3465 - 3471 (2010)
The homotetrameric flavoprotein pyranose 2-oxidase (P2Ox) has several proposed biotechnological applications, among others as a biocatalyst for carbohydrate transformations toward higher-value products. To improve some of the catalytic properties of P2Ox from Trametes multicolor, we selected a semirational enzyme engineering approach, namely, saturation mutagenesis of the amino acid His 450 located at a pivotal point of the active site loop and subsequent screening of the libraries thus obtained for improved activity with the sugar substrate D-galactose. A variant with improved catalytic characteristics identified was H450G, which showed a significant, 3.6-fold decrease In KM together with a 1.4-fold increase in κcat for its substrate D-galactose and an overall improvement in the catalytic efficiency by a factor of 5. By combining H450G with other amino acid replacements, we obtained the P2Ox variants H450G/V546C and H450G/E542K/V546C, which can be of interest for applications in food industry due to their increased activity with D-galactose, high activity with D-glucose, and considerably increased stability for the latter variant. While the His-tagged recombinant wild-type enzyme strongly prefers D-glucose to D-galactose as its substrate, H450G/E542K/V546C converts both sugars, which are found in lactose hydrolysates, concomitantly, as was shown by laboratory-scale biotransformation experiments. The 2-keto sugars thus obtained can conveniently be reduced to the corresponding ketoses D-fructose and D-tagatose. 2010 American Chemical Society.
Biochemical characteristics of Trametes multicolor pyranose oxidase and Aspergillus niger glucose oxidase and implications for their functionality in wheat flour dough
Decamps, Karolien,Joye, Iris J.,Haltrich, Dietmar,Nicolas, Jacques,Courtin, Christophe M.,Delcour, Jan A.
, p. 1485 - 1492 (2012)
Similar to glucose oxidase (GO), pyranose oxidase (P2O) may well have desired functionalities in some food applications in general, particularly breadmaking. As its name implies, P2O oxidises a variety of monosaccharides. P2O purified from a culture of Trametes multicolor (P2O-Tm) had high affinity towards d-glucose (KM = 3.1 mM) and lower affinity to other monosaccharides. GO from Aspergillus niger (GO-An) had a KM value of 225 mM towards glucose, which points to a significant difference in glucose affinity between the two enzymes. Furthermore, P2O-Tm had higher affinity towards O2 (KM = 0.46 mM) than GO-An (KM = 2.9 mM). Dehydroascorbic acid did not accept electrons in the reactions catalysed by P2O-Tm and GO-An. For the same activity towards glucose in saturating conditions, the rate of ferulic acid oxidation in a model system and of thiol oxidation in a wheat flour extract were higher with P2O-Tm, than with GO-An. The demonstrated differences in properties and functional features between P2O-Tm and GO-An allow prediction of differences in functional behaviour of the enzymes, in food applications.
CONVENIENT, LABORATORY PROCEDURE FOR PRODUCING SOLID D-arabino HEXOS-2-ULOSE (D-GLUCOSONE)
Liu, Te-ning E.,Wolf, Beverly,Geigert, John,Neidleman, Saul L.,Chin, Janice D.,Hirano, David S.
, p. 151 - 158 (1983)
The production of solid D-arabino-hexos-2-ulose (D-glucosone) from D-glucose by use of an enzyme, pyranose-2-oxidase (EC 1.1.3.10), is described.The enzyme is extracted from the mycelia of Polyporus obtusus, partially purified, and then immobilized on activated CH-Sepharose 4B.The enzymic conversion of D-glucose into D-glucosone is simple and convenient, and provides a product free from residual D-glucose.Lyophilization of the filtered reaction-solution yields the product, solid D-glucosone.Assay methods have been developed for monitoring the enzymic reaction and evaluating the purity of the final product.
CLEAVAGE OF D-arabino-HEXOS-2-ULOSE AND GLYOXAL WITH HYDROGEN PEROXIDE
Vuorinen, Tapani
, p. 319 - 326 (1984)
The kinetics of the cleavage of D-arabino-hexos-2-ulose (1) and of glyoxal (2) with hydrogen peroxide in alkaline water and in 44percent (w/w) ethanol-water solutions (pOH 0.5-5) were studied over a temperature range of -25 to +25 deg C.The relative rate of the competing reactions of 1 with the cleavage in 0.03-1M sodium hydroxide was determined from the rate of formation of hydrogen peroxide in the oxidation of D-glucose to 1 with 2-anthraquinonesulfonic acid in the presence of oxygen at 25 and 40 deg C.The cleavages of both 1 and 2 were firs-order with respect to hydrogen peroxide, and also to hydroxyl ion at low alkalinities.The rate of cleavage of 1 reached a maximum at pOH ca. 2.5, whereas the competing reactions of 1 and the cleavage of 2 were constantly accelerated with increasing hydroxyl-ion concentration.Unlike 2, compound 1 was cleaved more rapidly in ethanol-water than in water.The activation energies of the cleavage of 1 and 2, and the competing reactions of 1, were 49, 57, and 65 kJ.mol-1, respectively.
OXIDATION OF D-FRUCTOSE WITH VANADIUM(V): A KINETIC APPROACH
Olavi, P.,Virtanen, I.,Kurkisuo, Sinikka
, p. 215 - 224 (1985)
The kinetics of the oxidation of D-fructose with vanadium(V) in perchloric acid have been studied.The reaction is of first order with respect to the , but the values of the rate constant increase slightly with increasing .In the range from 0.002-0.02M V(V), the inverse of the second-order rate constant is linearly related to the inverse of .Sodium hydrogensulfate and perchlorate accelerate the reaction, the effect of the former salt being greater.At a constant +> and ionic strength, the reaction is of first order with respect to ->.At constant ionic strenghth, the reaction is of third order with respect to +>.The activation parameters have been determined.The data obtained have been compared with those for simpler mino- and poly-hydric alcohols.A possible three-step mechanism involving C-H bond fission and yielding glucosones as primary products has been suggested.
AN IMPROVED PREPARATION OF 3-DEOXY-D-erythro-HEXOS-2-ULOSE VIA THE BIS(BENZOYLHYDRAZONE) AND SOME RELATED CONSTITUTIONAL STUDIES
Madson, Michael A.,Feather, Milton S.
, p. 183 - 192 (1981)
Sugar osazones and glycosuloses rapidly and quantitatively react with hydroxylamine to produce oximes that give trimethylsilyl derivatives suitable for g.l.c. and mass spectral analysis.The reaction of D-glucose with benzoylhydrazine to give the bishydrazone of 3-deoxy-D-erythro-hexos-2-ulose (1) was re-investigated, together with the conversion of this compound to the hexosulose.Although by-products are produced in the reaction, including the bis(benzoylhydrazone) (osazone) of D-glucose, the major product is the monohydrate of the bis(benzoylhydrazone) of 1 (colorless).The anhydrous (yellow) form can be prepared from the monohydrate by crystallization from absolute ethanol and has quite different physical properties.Improvements of the original preparation are described that allow the preparation of the bishydrazone and its subsequent conversion to 1 via transhydrazonation in 44percent overall yield, and with no detectable contamination by D-glucose or D-glucosone.Evidence is presented that the previously reported cyclic form of the bis(benzoylhydrazone) of D-glucose is the bis(benzoylhydrazone) (monohydrate) of 1.
Bioconversion of d-glucose into d-glucosone by immobilized glucose 2-oxidase from Coriolus versicolor at moderate pressures
Karmali, Amin,Coelho, José
, p. 168 - 173 (2011)
The immobilized glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2- oxidoreductase, EC 1.1.3.10) from Coriolus versicolor was used to convert d-glucose into d-glucosone at moderate pressures, up to 150 bar, with compressed air in a modified commercial batch reactor. Several parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, different forms of immobilized biocatalysts, glucose concentration, pH, temperature and the presence of catalase. Glucose 2-oxidase (GOX2) was purified by immobilized metal affinity chromatography on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. Purified enzyme and catalase were immobilized into a polyethersulfone (PES) membrane in the presence of glutaraldehyde and gelatin. Enhancement of the bioconversion of d-glucose was done by the pressure since an increase in the pressure with compressed air increases the conversion rates. The optimum temperature and pH for bioconversion of d-glucose were found to be 62 °C and pH 6.0, respectively and the activation energy (E a) was 28.01 kJ mol-1. The apparent kinetic constants (V′max, K′m, K′cat and Kcat/K′m) for this bioconversion were 2.27 U mg-1 protein, 11.15 mM, 8.33 s-1 and 747.38 s-1 M-1, respectively. The immobilized biomass of C. versicolor as well as crude extract containing GOX2 activity were also useful for bioconversion of d-glucose at 65 bar with a yield of 69.9 ± 3.8% and 91.3 ± 1.2%, respectively. The immobilized enzyme was apparently stable for several months without any significant loss of enzyme activity. On the other hand, this immobilized enzyme was also stable at moderate pressures, since such pressures did not affect significantly the enzyme activity.
A conserved active-site threonine is important for both sugar and flavin oxidations of pyranose 2-oxidase
Pitsawong, Warintra,Sucharitakul, Jeerus,Prongjit, Methinee,Tan, Tien-Chye,Spadiut, Oliver,Haltrich, Dietmar,Divne, Christina,Chaiyen, Pimchai
, p. 9697 - 9705 (2010)
Pyranose 2-oxidase (P2O) catalyzes the oxidation by O2 of D-glucose and several aldopyranoses to yield the 2-ketoaldoses and H 2O2. Based on crystal structures, in one rotamer conformation, the threonine hydroxyl of Thr169 forms H-bonds to the flavin-N5/O4 locus, whereas, in a different rotamer, it may interact with either sugar or other parts of the P2O·sugar complex. Transient kinetics of wild-type (WT) and Thr169 → S/N/G/A replacement variants show that D-Glc binds to T169S, T169N, and WT with the same Kd (45-47mM), and the hydride transfer rate constants (kred) are similar (15.3-9.7 s -1 at 4 °C ). kred of T169G with D-glucose (0.7 s -1, 4 °C) is significantly less than that of WT but not as severely affected as in T169A (kred of 0.03 s-1 at 25 °C). Transient kinetics of WT and mutants using D-galactose show that P2O binds D-galactose with a one-step binding process, different from binding of D-glucose. In T169S, T169N, and T169G, the overall turnover with D-Gal is faster than that of WT due to an increase of kred. In the crystal structure of T169S, Ser169 Oγassumes a position identical to that of Oγ1 in Thr169; in T169G, solvent molecules may be able to rescue H-bonding. Our data suggest that a competent reductive half-reaction requires a side chain at position 169 that is able to form an H-bond within the ES complex. During the oxidative half-reaction, all mutants failed to stabilize a C4a-hydroperoxyflavin intermediate, thus suggesting that the precise position and geometry of the Thr169 side chain are required for intermediate stabilization.
Temperature decrease (30-25 °c) influence on bi-enzymatic kinetics of D-glucose oxidation
Ene, Manuela Diana,Maria, Gheorghe
, p. 19 - 24 (2012)
Previous batch experiments reported by Maria et al. [1] for d-glucose oxidation in the presence of pyranose 2-oxidase (P2Ox from Coriolus sp. expressed in E. coli) and catalase at 30 °C and optimal pH = 6.5 have been extended to a lower temperature of 25 °C. This modification influences the process performance in different ways, leading to a higher activity of catalase for decomposing H2O2 by-product, thus maintaining its concentration to negligible levels. While the presence of catalase has a favourable effect at 30 °C on prolonging P2Ox life-time, a quick P2Ox inactivation is observed at 25 °C due to the high levels of the resulted oxidative intermediates. While the P2Ox activity does not vary too much in the range of 25-30 °C, a significant decline of the main reaction rate with the increase of catalase/P2Ox ratio is reported for both temperatures. Estimated rate constants of a proposed kinetic model are compared to the literature data, being used to predict the favourable operating conditions for this complex bi-enzymatic system.
Determination of glyceraldehyde formed in glucose degradation and glycation
Usui, Teruyuki,Yoshino, Miku,Watanabe, Hirohito,Hayase, Fumitaka
, p. 2162 - 2168 (2007)
Glyceraldehyde (GLA) was determined in glucose degradation and glycation. GLA was detected as a decahydroacridine-1,8-dione derivative on reversed phase HPLC using cyclohexane-1,3-dione derivatizing reagent. The glucose-derived GLA level was higher than the glycation-derived GLA level, because GLA was converted to intermediates and advanced glycation end products (AGE) in glycation. GLA was also generated from 3-deoxyglucosone and glucosone as intermediates of glucose degradation and glycation. This study suggests that glyceraldehyde is generated by hyperglycemia in diabetes, and that it is also formed in medicines such as peritoneal dialysis solution.
