Enzymatic Oxidation and Separation of Various Saccharides with Immobilized Glucose Oxidase

Abstract

Glucose oxidase from Aspergillus niger, the specific enzyme for beta-D-glucose oxidation, can also oxidize other related saccharides at very slow or negligible rates. The present study aimed to compare the kinetics of D-glucose oxidation using immobilized glucose oxidase on bead cellulose for the oxidation of related saccharides using the same biocatalyst. The significant differences were observed between the reaction rates for D-glucose and other saccharides examined. As a result, k (cat)/K (M) ratio for D-glucose was determined to be 42 times higher than D-mannose, 61.6 times higher than D-galactose, 279 times higher than D-xylose, and 254 times higher than for D-fructose and D-cellobiose. On the basis of these differences, the ability of immobilized glucose oxidase to remove D-glucose from D-cellobiose, D-glucose from D-xylose, and D-xylose from D-lyxose was examined. Immobilized catalase on Eupergit and mixed with immobilized glucose oxidase on bead cellulose or co-immobilized with glucose oxidase on bead cellulose was used for elimination of hydrogen peroxide from the reaction mixture. The accelerated elimination of D-glucose and D-xylose in the presence of co-immobilized catalase was observed. The co-immobilized glucose oxidase and catalase were able to decrease D-glucose or D-xylose content to 0-0.005% of their initial concentrations, while a minimum decrease of low oxidized saccharides D-xylose, D-cellobiose, and D-lyxose, respectively, was observed.

Mediatorless, Reversible Optical Nanosensor Enabled through Enzymatic Pocket Doping

“…In addition, a comparison of the catalytic efficiency shown in Figure S4 of the Supporting Information shows that although mannose is catalyzed to a measureable extent, its catalytic turnover is over 20 times slower than that of glucose, requiring over an hour of incubation to achieve a fraction of the activity achieved in 3 min with glucose. This observation is in agreement with previous reports of GOx having a k cat / K M for mannose that is 42 times smaller than that of glucose, and it is conferred by the preferred oxidation of glucose in the presence of other sugars . This catalytic selectivity, combined with the fact that hexoaldose concentrations of competing sugars are typically two orders of magnitude below that of glucose, indicate adequate glucose specificity of the GOx‐SWCNT sensors for in vivo applications …”

New biotechnological perspectives of a NADH oxidase variant from Thermus thermophilus HB27 as NAD+-recycling enzyme

“…Water-forming NADH-oxidases are more interesting for biotechnological applications due to the innocuous nature of water as a byproduct. Conversely, the recent application of catalases for in-situ elimination of hydrogen peroxide [18] would boost the application of H 2 O 2 -forming NADH-oxidases in biocatalysis.…”

Glucose-induced decomposition of layer-by-layer films composed of phenylboronic acid-bearing poly(allylamine) and poly(vinyl alcohol) under physiological conditions

“…The catalytic activity of GOx for mannose and fructose is reported to be 2.3% and 0.4%, respectively, of the activity for glucose. 48 The film decomposition observed upon exposure to fructose is most likely due to the competitive binding of fructose to PBA-PAH in the film. Fructose is known to bind PBA rather strongly; the binding constants of fructose, mannose, and glucose to PBA are 160 M À1 , 13 M À1 , and 4.6 M À1 , respectively.…”