1)      4,6-O-Benzylidene-4-methylumbelliferyl-β-cellotrioside

2)      β-glucosidase (Thermotoga maritima)

Upon incubation with a cellulase (endo-1,4-β-glucanase) enzyme, the functionalised trisaccharide is cleaved and the ancillary β-glucosidase can act to hydrolyse the fragment containing the 4-methylumbelliferyl group. The rate of formation of 4-methylumbelliferyl is directly proportional to the cellulase (endo-1,4-β-glucanase) activity. The assay reaction is terminated and full fluorescence obtained from the fluorophore by the addition of Tris buffer.