Binding isotherms of EG1 and its derivatives for different cellulosic substrates. Reaction mixtures containing different concentrations of recombinant protein (EG1, 1.5 to 13.8 μmol/liter; CBM-CBM-CD, 2.4 to 12.2 μmol/liter; CBM-CD-CBM, 1.5 to 7.1 μmol/liter) and 10 mg cellulosic substrate in a final volume of 0.5 ml of 50 mM potassium phosphate buffer (pH 7.5) were incubated at 4°C with constant agitation in an inversion-action shaker (150 inversions per min). Symbols: ◇, EG1; □, CBM-CBM-CD; Δ, CBM-CD-CBM. Bold lines, RAC; broken lines, FP; dotted lines, Avicel PH-101 (Fluka).