Article ID Journal Published Year Pages File Type
6490478 Journal of Biotechnology 2016 8 Pages PDF
Abstract
The gene xylB from Caulobacter crescentus has been cloned and expressed in Escherichia coli providing a high yield of xylose dehydrogenase (XylB) production and excellent purity (97%). Purified recombinant XylB showed an absolute dependence on the cofactor NAD+ and a strong preference for d-xylose against other assayed mono and disaccharides. Additionally, XylB showed strong stability when stored as freeze-dried powder at least 250 days both at 4 °C and room temperature. In addition, more than 80% of the initial activity of rehydrated freeze-dried enzyme remained after 150 days of incubation at 4 °C. Based on these characteristics, the capability of XylB in d-xylose detection and quantification was studied. The linearity of the method was maintained up to concentrations of d-xylose of 10 mg/dL and the calculated limits of detection (LoD) and quantification (LoQ) of xylose in buffer were 0.568 mg/dL and 1.89 mg/dL respectively. Thus, enzymatic detection was found to be an excellent method for quantification of d-xylose in both buffer and urine samples. This method can easily be incorporated in a new test for the diagnosis of hypolactasia through the measurement of intestinal lactase activity.
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Physical Sciences and Engineering Chemical Engineering Bioengineering
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