Hydrolysis of filter paper by Trichoderma viride cellulase. Effect of assay conditions, 0.5 or 1.0 ml enzyme + 1 ml buffer pH 4.8 + 25, 50, or 100 mg Whatman No. filter paper. Units = μmol of glucose/min based on dilution to give 2 mg of glucose. White triangle, 30 min incubation 50°C; white circle, 60 min incubation 50°C; white square, 120 min incubation 50°C.