3.4 Characterisation of biochemical properties
The pH effect on rAGL activity was shown in Fig. 4a. rAGL activity reached its maximum at pH 4.0. Under the standard condition, it showed high enzymatic activity (>90% of maximum value) between pH 3.0 and pH 5.0. Furthermore. rAGL was stable at pH 3.0–4.5, and retained 99% and 97% activity after incubation at pH 4.0 for 48 h and 72 h, respectively (Fig. 4b).
The optimum temperature for rAGL was 65 °C, and it has high activity between 60 °C and 65 °C (Fig.4c). rAGL was stable between 37 °C and 55 °C, and remained more than 80% activity after 60 min of incubation (Fig.4d). However, when the temperature was kept at 65 °C for 15 min, rAGL lost 50% of its activity.
In this study, the metal requirement of rAGL was investigated using 10 mM metal ions (Cu2+, Ca2+, Mg2+, Mn2+, Zn2+, Fe3+ and Fe2+). rAGL was pre-incubated with each metal ion, and its activity was gauged. As is displayed in Fig.5, none of these metals significantly affected rAGL activity, which suggested that this enzyme is insensitive to the metal ions under the experimental conditions.
Figure 4
Figure 5