2.5 mL; xylose dehydrogenase (60 U/mL) /
xylose mutarotase (2 mg/mL)
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|Content:|| 2.5 mL; xylose dehydrogenase (60 U/mL) / |
xylose mutarotase (2 mg/mL)
|Storage Temperature:||Below -10oC|
|Formulation:||In 50% (v/v) glycerol|
|Stability:||> 2 years below -10oC|
|EC Number:|| XDH: 184.108.40.206 |
|CAS Number:|| XDH: 62931-20-8 |
|Synonyms:|| XDH: D-xylose 1-dehydrogenase; D-xylose:NAD+ 1-oxidoreductase |
XMR: Aldose 1-epimerase
|Concentration:||Supplied at ~ 60 U/mL|
|Specificity:|| Interconversion of the α- and β-anomeric forms of D-xylose is catalysed by xylose mutarotase (XMR) (1). |
(1) α-D-Xylose ↔ β-D-xylose.
The β-D-xylose is oxidised by NAD+ to D-xylonic acid in the presence of β-xylose dehydrogenase (β-XDH) at pH 7.5 (2).
(2) β-D-Xylose + NAD+ ↔ D-xylonic acid + NADH + H+
|Specific Activity:|| XDH: ~ 60 U/mL at pH 7.5 and 25oC / |
XMR: 2 mg/mL
|Unit Definition:||One Unit of xylose dehydrogenase is defined as the amount of enzyme required to produce one µmole of NADH from NAD+ per minute at 25oC.|
|Application examples:||For the measurement of D-xylose, especially in broths and hydrolysates of plant material and polysaccharides. Refer to the D-XYLOSE Assay Kit booklet (Megazyme cat. no. K-XYLOSE) for directions of use.|
McCleary, B. V., McKie, V. A., Draga, A., Rooney, E., Mangan, D. & Larkin, J. (2015). Carbohydrate Research, 407, 79-96.
A range of α-L-arabinofuranosyl-(1-4)-β-D-xylo-oligosaccharides (AXOS) were produced by hydrolysis of wheat flour arabinoxylan (WAX) and acid debranched arabinoxylan (ADWAX), in the presence and absence of an AXH-d3 α-L-arabinofuranosidase, by several GH10 and GH11 β-xylanases. The structures of the oligosaccharides were characterised by GC-MS and NMR and by hydrolysis by a range of α-L-arabinofuranosidases and β-xylosidase. The AXOS were purified and used to characterise the action patterns of the specific α-L-arabinofuranosidases. These enzymes, in combination with either Cellvibrio mixtus or Neocallimastix patriciarum β -xylanase, were used to produce elevated levels of specific AXOS on hydrolysis of WAX, such as 32-α-L-Araf-(1-4)-β-D-xylobiose (A3X), 23-α-L-Araf-(1-4)-β-D-xylotriose (A2XX), 33-α-L-Araf-(1-4)-β-D-xylotriose (A3XX), 22-α-L-Araf-(1-4)-β-D-xylotriose (XA2X), 32-α-L-Araf (1-4)-β-D-xylotriose (XA3X), 23-α-L-Araf-(1-4)-β-D-xylotetraose (XA2XX), 33-α-L-Araf-(1-4)-β-D-xylotetraose (XA3XX), 23 ,33-di-α-L-Araf-(1-4)-β-D-xylotriose (A2+3XX), 23,33-di-α-L-Araf-(1-4)-β-D-xylotetraose (XA2+3XX), 24,34-di-α-L-Araf-(1-4)-β-D-xylopentaose (XA2+3XXX) and 33,34-di-α-L-Araf-(1-4)-β-D-xylopentaose (XA3A3XX), many of which have not previously been produced in sufficient quantities to allow their use as substrates in further enzymic studies. For A2,3XX, yields of approximately 16% of the starting material (wheat arabinoxylan) have been achieved. Mixtures of the α-L-arabinofuranosidases, with specific action on AXOS, have been combined with β-xylosidase and β-xylanase to obtain an optimal mixture for hydrolysis of arabinoxylan to L-arabinose and D-xylose.Hide Abstract
A highly effective approach to cofactor regeneration and subsequent membrane separation of bioconversion products: Kinetic parameters and effect of process conditions.
Bachosz, K., Zdarta, J., Marczak, Ł., Błażewicz, J. & Jesionowski, T. (2020). Bioresource Technology Reports, 9, 100365.
Bioconversion of monosaccharides is a process which can be used to obtain value-added compounds such as xylonic acid. In this study, we demonstrate enzymatic conversion of xylose with simultaneous cofactor regeneration using co-immobilized xylose dehydrogenase and alcohol dehydrogenase. The research is focused on the effect of process parameters, the buffer solutions used and inhibitors on the enzyme activity, as well as demonstrating the effective separation of substrates and products. In addition, kinetic parameters were determined and the Km and Vmax values after immobilization were found to be respectively 15-20% higher and 10% lower than the values for free proteins. Moreover, the highest NADH residual was recorded when TAPSO buffer was used, and it was shown that phenolic monomers do not significantly alter the bioconversion efficiency. Finally, the highest retention of xylonic acid, using membrane separation, was found to be about 90% at pH 9.Hide Abstract