Figure 3.

Experiment-1 of the time courses (y, mean $\pm \mathrm{SE},$ umol/mg protein) with describing model parameter estimates $\pm \mathrm{SE})$ of crude GH5-tCel5A1 enzyme preparation incubated with carboxymethyl cellulose (CMC) and Avicel as the substrate buffers in the presence or absence of N₂ gas purging and dithiothreitol (DTT) (5 mM) for up to 90–180 min, respectively, in examining the effects of auto-oxidation on GH5-tCel5A1 hydrolysis. (A) Responses (y, mean $\pm \mathrm{SE}$, n = 4 at each time point) of the crude GH5-tCel5A1 enzyme preparation incubated with the CMC substrate buffer without N₂ gas purging and the DTT (5 mM) for up to 90 min described according to a quadratic model (model parameter estimates $\pm \mathrm{SE})$ as: $Y=-0.036\left(\pm ,0.013\right)x-9.0e^{-4}\left(\pm ,1.3,e^{-4}\right){\mathrm{x}}^2$, P = 0.472 for the intercept; P = 0.009 for the linear parameter estimate; and P < 0.0001 for the quadratic parameter estimate; ${\mathrm{R}}^2$ = 0.927, n = 28; (B) Responses (y, mean $\pm \mathrm{SE}$, n = 4 at each time point) of the crude GH5-tCel5A1 enzyme preparation incubated with the Avicel substrate buffer without N₂ gas purging and DTT (5 mM) for up to 180 min described according to a quartic model (model parameter estimates $\pm \mathrm{SE})$ as: $Y=1.564{\left(\pm ,0.481\right)\mathrm{x}}^2-1.041{\left(\pm ,0.279\right)\mathrm{x}}^3+0.191{(\pm 0.049)\mathrm{x}}^4$, P = 0.244 for the intercept; P = 0.093 for the linear parameter estimate; P = 0.006 for the quadratic parameter estimate; P = 0.003 for the cubic parameter estimate; and P = 0.002 for the quartic parameter estimate;${\mathrm{R}}^2=0.727,\mathrm{n}=20$; (C) Responses (y, mean $\pm \mathrm{SE}$, n = 4 at each time point) of the crude GH5-tCel5A1 enzyme preparation incubated with the CMC substrate buffer with N₂ gas purging with DTT (5 mM) for a total of 90 min established according to a quadratic model (model parameter estimates $\pm \mathrm{SE})$ as: $Y=0.474\left(\pm ,0.229\right)+0.067\left(\pm ,0.012\right)x-4.6e^{-4}(\pm 1.0e^{-4}){\mathrm{x}}^2$; P = 0.049 for the intercept; P < 0.0001 for the linear parameter estimate; and P = 0.002 for the quadratic parameter estimate; ${\mathrm{R}}^2$ = 0.837, n = 32; (D) Responses (y, mean $\pm \mathrm{SE}$, n = 12 at each time point) of the crude tCel5A1 enzyme preparation incubated with the Avicel substrate buffer with N₂ gas purging and DTT (5 mM) for up to 180 min established according to a quadratic model (model parameter estimates $\pm \mathrm{SE})$ as: $Y=0.004\left(\pm ,0.001\right)x-2.0e^{-5}(\pm 7.462e^{-6}){\mathrm{x}}^2$, P = 0.006 for the slope estimate and P = 0.038 for the quadratic parameter estimate; ${\mathrm{r}}^2$= 0.167, n = 72); (E) the linear part (y, mean $\pm \mathrm{SE}$, n = 4 at each time point) (0, 7.5 and 15 min) part of the above-(C) time course experiment with the crude GH5-tCel5A1 enzyme preparation incubated with the CMC buffer at 37 °C and pH 7.4 with N₂ gas purging and DTT (5 mM) established (model parameter estimates $\pm \mathrm{SE})$ as: $y=0.149\left(\pm ,0.010\right)\mathrm{x}$, P = 0.096 for the intercept and P < 0.0001 for the slope, ${\mathrm{r}}^2$ = 0.963, n = 12; and (F) the linear part (y, mean $\pm \mathrm{SE}$, n = 12 at each time point) (0, 15 and 30 min) of the above-(D) time course experiment with the crude tCel5A1 enzyme preparation incubated with the Avicel substrate buffer at 37 °C and pH 7.4 with N₂ gas purging and DTT (5 mM) established (model parameter estimates $\pm \mathrm{SE})$ as: $y=0.008\left(\pm ,0.002\right)x$, P = 0.909 for the intercept and P < 0.0001 for the slope, ${\mathrm{r}}^2=0.358,\mathrm{n}=36$.