The crude extract was sequentially fractionated
with ammonium sulfate at 0-30% (F1), 30-60%
(F2), and 60-90% (F3) saturation. In the following,
each fraction was maintained for about 10 h at 8°C
temperature and centrifuged at 12,000 g for 30 min
at 4°C, in order to obtain the precipitated proteins.
The precipitates were resuspended in Tris-HCl buffer
50 mM, pH 7.5, then dialyzed against the same
buffer and kept at -20°C until the fulfillment of the
experiments.