The Bicinchoninic Acid (BCA) Protein Assay primarily relies on two reactions. Firstly, the peptide bonds in the protein sample reduce Cu²⁺ ions, in a temperature dependent reaction, from the copper solution to Cu⁺. The amount of Cu²⁺ reduced is proportional to the amount of protein present in the solution. Next, two molecules of bicinchoninic acid (BCA) chelate with each Cu⁺ ion, forming a purple-coloured product that strongly absorbs light at a wavelength of 562 nm that is linear for increasing protein concentrations between the range of 0,02 to 2 mg/ml. The amount of protein present in a solution can be quantified by measuring the absorption spectra and comparing with protein solutions with known concentrations.
The Bicinchoninic Acid (BCA) Protein Assay is suitable for quantifying protein solutions in 1 ml cuvettes or in microwells.
