megazyme.com VS.

jenabioscience.com

The K-XYLX6-1V pack size has been discontinued (read more) The XylX6 assay reagent for the measurement of endo -xylanase (endo -1,4-β-xylanase) contains two components; 1) 4,6- O -(3-Ketobutylidene)-4-nitrophenyl-β-D-4 5 -glucosyl-xylopentaoside and 2) β-xylosidase. The ketone blocking group prevents any hydrolytic action by the β-xylosidase or other exo -acting glycosidases on the XylX6 substrate. Incubation with an endo -xylanase generates a non-blocked colourimetric oligosaccharide that is rapidly hydrolysed by the ancillary β-xylosidase. The rate of formation of 4-nitrophenol is therefore directly related to the hydrolysis of XylX6 by the endo -xylanase. The reaction is terminated and the phenolate colour is developed on addition of Tris buffer solution (pH = 10.0). Need to measure other enzyme activities? View our complete list of assay kits for measurement of enzyme activity. Note that standard curves relating the absorbance obtained using the XylX6 assay to endo -xylanase activity on the native substrates, wheat arabinoxylan and beechwood xylan, are provided in the Supporting Information file under the Documents tab.