Colourimetric oligosaccharides with a chemically-defined structure are available for the measurement of the activity of endo-xylanases, exo-xylosidases and α-L-arabinofuranosidases. These are suitable for use in both manual and high throughput automated analysis applications. The activity of the enzyme assayed can be determined directly by measuring the absorption increase at 400 nm which corresponds to the release of the nitrophenolate ion in solution.
Insoluble and soluble chromogenic enzyme substrates derived from arabinoxylan and xylan (birchwood) have been prepared for the detection and specific measurement of endo-xylanase activity. These substrates produce a colourimetric response upon incubation with a suitable xylanase that can be related to enzyme activity through the standard curve provided (soluble substrates only) or used for screening on agar plates. The insoluble substrate is also available in tablet form to increase accuracy and convenience for the end-user for quantitative assays.
Figure: Schematic representation of the use of dyed polysaccharides (soluble) for the assay of endo-hydrolase activity.
1 McCleary, B. V., McKie, V. A., Draga, A., Rooney, E., Mangan, D. & Larkin, J. (2015). Hydrolysis of wheat flour arabinoxylan, acid-debranched wheat flour arabinoxylan and arabino-xylo-oligosaccharides by b-xylanase, α-L-arabinofuranosidase and b-xylosidase. Carbohydrate Research, 407, 75-96.