FIGURE 1.
Calibration data. A–C, shown are the calibration plots to determine ΔappH for each enzyme. Data on the ordinate are integrated values from the ITC runs shown in Fig. 2, and the data on the abscissa have been measured using the BCA assay on the same samples. The integration was carried out from time t = 0 to t = 970 s. All analyses are performed on 8 g/liter RAC, 30 °C, pH 5.0. Panel A shows varied doses (200–1000 nm) of TrCel5A added to RAC. Panel B shows varied doses of (100–500 nm) TrCel12A added to RAC. Panel C shows varied doses of TrCel7B (50–250 nm) added to 8g/liter RAC. In both A and C the different symbols represent runs on different batches of substrate. μmol values in A, B, and C were measured in triplicate, the coefficient of variation was under 5% in all cases (error bars are not shown). From the slopes: ΔappH of TrCel7B = −1.7 kJ/mol, TrCel5A = −3.0 kJ/mol, and TrCel12A = −5.4 kJ/mol.