2.5.6. Soluble proteins
Bio-Rad Protein Assay (Bio-Rad Laboratories) based on the
method of Bradford was used in micro-method format to
determine protein concentration. Briefly, a solution of Bradford
reagent (1:4, reagent:milli-Q water) was prepared and filtered
using Whatman 4 filter. Ten ll of sample and 200 ll of Bradford
solution were placed in a multi-well microplate. Samples were
incubated for 5 min at room temperature, and the absorbance
was measured at 595 nm. Sample blank and reagent blank were
also analysed. A calibration curve was constructed using BSA
(0.05–0.5 mg/ml). All measurements were performed in triplicate.
Results were expressed as mg BSA/g.