Use BSA (bovine serum albumin) 1mg/ml stock solution (1ml Eppendorf tubes) for standard curve.
Place 0, 2, 5, 10, 15, 20µg (=µl) BSA into plastic cuvette. Use 2-5µl of sample.
Bring volume up to 800µl with H2O.
Add 200µl dye (Biorad Protein Assay Dye Reagent Concentrate)
Cover cuvettes with parafilm and mix gently. The colour of sample (intensity of blue) should be between the two extremes of the standard curve. Avoid precipitation by adding protein first, H2O second and dye last.
Measure protein concentration with spectrophotometer at 595 nm