• Assay Type Detection Kit
  • Sample Types Serum, Plasma, Urine, Cell Lysates, Tissue Homogenates
  • Sensitivity 1.68 µg/mL
  • Species All Species
  • Assay Duration 2 Hours
  • Samples/Plate 41 in Duplicate
  • Readout Colorimetric, 560 nm
  • Standard Curve BCA Protein Dual Range Colorimetric Detection Kit
  • Description

    Assay Principle: 

    The BCA Protein Dual Range Colorimetric Detection Kit quantitatively measures total protein levels in serum, plasma, urine, cell lysates, and tissue homogenates. The BCA Protein Dual Range Colorimetric Detection Kit is a Detection Kit with a run time of 2 hours. Please read the complete kit insert for more information before performing this assay.

    Use our provided Bovine Serum Albumin Standard to generate a standard curve for the assay. Pipette the standards or diluted samples into a transparent microtiter plate. Add BCA Color Solution to each well, tapping the plate to ensure sufficient mixing of reagents. Then, incubate the mixture at 37°C for 2 hours. The color-generating reaction occurs between the BCA Color Reagent and Protein within the sample or standard.

    After the 2-hour incubation, use a plate reader to detect and record the generated signal at 560nm. Use the intensity and the standard curve to calculate the Protein concentration in the samples.


    Protein determination is one of the most common operations performed in biochemical research. The bicinchoninic acid (BCA) assay principle is similar to the Lowry assay. It relies on forming a Cu2+-protein complex under alkaline conditions, then reducing the Cu2+ to Cu1+. The amount of reduction is proportional to the protein present. Cysteine, cystine, tryptophan, tyrosine, and peptide bonds can reduce Cu2+ to Cu1+. BCA forms a purple-blue complex with Cu1+ in alkaline environments, thus providing a basis to monitor the reduction of alkaline Cu2+ by proteins.

    The method combines the well-known reduction of Cu2+ to Cu1+ by protein in an alkaline medium (the biuret reaction). Using a unique bicinchoninic acid reagent, it offers highly sensitive and selective colorimetric detection of the cuprous cation (Cu+1). The purple-colored reaction product of this assay is formed by the chelation of two molecules of BCA with one cuprous ion. This water-soluble complex exhibits a strong absorbance at 562nm that is nearly linear with increasing protein concentrations over a broad working range (6-1,000 µg/mL).