Protein measurement
Determination of the protein content is based on the Bradford method (Bradford, 1976) using the Coomassie Protein assay reagent (Pierce, Rockford). Cells were washed with PBS following exposure to cadmium chloride. Precipitation with 6.5% TCA for 10 min followed and dissolution of the proteins was achieved with the addition of NaOH (1 M) (overnight at room temperature). Aliquots of standard albumin or sample were pipetted in 96 polystyrene well plates and mixed with equal volume of the Coomassie reagent. The absorbance was measured at 595 nm using the microplate spectrophotometer system (Spectra max190-Molecular Devices). Results were analyzed with the Soft max pro software (version 2.2.1) and are presented as percentage of control values.