Bio-Rad Protein Assay: Bradford

Materials:  Bradford Reagent- Bio-Rad sells a ready-to-use reagent (Cat.#500-0006) that can be stored at 4C.  Bovine serum albumin (BSA)(1mg/ml)-dissolve with water or 0.15M NaCl for standard curve.  1ml plastic cuvette. Standard curve: Standards:1mg/ml BSA BSA(µl) Water(µl) Bio-Rad reagent 1:5 dilute in water(µl) 0 25 975 5 20 975 10 15 975 15 10 975 20 5 975 25 0 975 Note: do standard curve in duplicate  Wait for 5 minutes before reading at 595nm. Samples:  Add 5µl cell lysates (varies according to protein concentration) into 995µl 1:5 diluted Bio-Rad reagent (dilution factor 1:200) and incubate at room temperature for 5 minutes and read absorbance at 595nm. Save standard curve:  In theory, you need to do standard curve every time. But you can save the standard curve for future use, just for convenience, we only need the relatively amounts of protein concentration.  You may load about ~ 40-60 µg of total protein for Western bloting assay.