Physicochemical characteristics of β‑glucosidases
Optimal temperatures and pH for the activity of Bgl1
and Bgl2 were determined using pNPGlc as the substrate.
Assays were either performed at pH 5.0 and various
temperatures (30–70°C) or at 30°C in variable pH
conditions (2.0–8.0) using either 50 mM glycine–HCl
(pH 2.0), 50 mM citrate/acetate (pH 3.0–7.2) or potassium
phosphate (pH 7.0–8.2) buffer. When the temperature
was varied, the pH of the citrate buffer was adjusted
accordingly. Stability of Bgl1 and Bgl2 depending on pH
and temperature was analyzed as follows: enzymes were
incubated at 30°C for up to 2 h at various pH values (2.0–
8.0) or at various temperatures (30–70°C) for up to 2 h in
50 mM citrate buffer, pH 5.0. Residual glucosidase activity
was then assayed at 30°C in 50 mM citrate buffer, pH
5.0.