Cellulase Assay Kit (CellG5 Method)

The CellG5 assay reagent for the measurement of endo-cellulase (endo-1,4-β-glucanase) contains two components;
1) 4,6-O-(3-Ketobutylidene)-4-nitrophenyl-β-D-cellopentaoside (BPNPG5) and 2) thermostable β-glucosidase. The ketone blocking group prevents any hydrolytic action by the β-glucosidase on BPNPG5.  Incubation with an endo-cellulase generates a non-blocked colourimetric oligosaccharide that is rapidly hydrolysed by the ancillary β-glucosidase. The rate of formation of 4-nitrophenol is therefore directly related to the hydrolysis of BPNPG5 by the endo-cellulase. The reaction is terminated and the phenolate colour is developed on addition of Tris buffer solution (pH 9.0).
The CellG5 assay represents a huge step forward in the methodology for the measurement of cellulase that traditionally relied on substrates such as CM-cellulose, Avicel, cellooligosaccharides, filter paper or dyed polysaccharides including CMC Congo red or cellulose azure.

Cellulase Assay Kit (CellG5 Method)
Product Code
120 / 240 assays (manual) / 480 (auto-analyser)
60 / 120 assays (manual) / 240 (auto-analyser)

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Colourimetric method for the determination of 
-1,4-β-glucanase (cellulase) in enzyme preparations and fermentation products

(1) 3-Ketobutylidene-G5-β-PNP + H2O → Blocked-GX + G(5-X)-β-PNP

                (thermostable β-glucosidase)
(2) G(5-X)-β-PNP + H2O → D-glucose + PNP

      (alkaline solution)
(3) PNP → phenolate ion (yellow colour)
Note: PNP = 4-nitrophenol

Kit size:
K-CellG5-4V 120 / 240 assays (manual) / 480 (auto-analyser)
K-CellG5-2V 60 / 120 assays (manual) / 240 (auto-analyser)

Method:                         Spectrophotometric at 400 nm
Total assay time:           10 min
Detection limit:                1.2 x 10-3 U/mL
Application examples:
Fermentation broths, industrial enzyme preparations and biofuels research
Method recognition:     Novel method


  • Very cost effective
  • All reagents stable for > 4 years
  • Completely specific for cellulase (endo-1,4-glucanase)
  • Generally applicable and highly sensitive
  • Simple format. Well suited to automation
  • Standard included

Prediction of potential malt extract and beer filterability using conventional and novel malt assays.

Cornaggia, C., Evans, D. E., Draga, A., Mangan, D. & McCleary, B. V. (2019). Journal of Institute of Brewing, In Press.

Novel substrates for the measurement of endo-1,4-β-glucanase (endo-cellulase).

McCleary, B. V., Mangan, D., Daly, R., Fort, S., Ivory, R. & McCormack, N. (2014). Carbohydrate Research, 385, 9-17.

Quantitative fluorometric assay for the measurement of endo-1,4-β-glucanase.

Mangan, D., McCleary, B. V., Liadova, A., Ivory, R. & McCormack, N. (2014). Carbohydrate Research, 395, 47-51.

A novel automatable enzyme-coupled colorimetric assay for endo-1,4-β-glucanase (cellulase).

Mangan, D., Cornaggia, C., McKie, V., Kargelis. T. & V. McCleary, B. V. (2016). Analytical and Bioanalytical Chemistry, 408(15), 4159-4168.

Complete genome sequence of Bacillus sp. 275, producing extracellular cellulolytic, xylanolytic and ligninolytic enzymes.

Gong, G., Kim, S., Lee, S. M., Woo, H. M., Park, T. H., & Um, Y. (2017). Journal of Biotechnology, 254, 59-62.