Sodium dodecyl sulfate polyacrylamide gel electrophoresis
(SDS-PAGE) was carried out according to the method of Laemmli
(1970), using 12.5% resolving gel and 4% stacking gel. Electrophoresis
was carried out in a Bio-Rad mini-protean electrophoresis
system at a constant voltage
120 V. The gels were analyzed using TotalLab Quant software
(Nonlinear Dynamics Ltd., Newcastle, UK). The molecular weights
were estimated by comparing Rf values on the gel with those of the
protein standards. The relative amount of each protein band in SDSPAGE
patterns was the optical density of each protein band to total
optical densities of all protein bands in the same lane.