The Micro Bicinchoninic Acid (BCA) Protein Assay is a highly sensitive colorimetric assay that is compatible with detergent solubilized protein solutions. This modification of the Bicinchoninic Acid (BCA) Protein Assay is suitable for dilute protein samples (0.5-20µg/ml).

The Micro 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 chelate with each Cu+ ion, forming a purple-colored product that strongly absorbs light at a wavelength of 562nm. The assay uses concentrated solutions and extended incubation times for the detection of dilute protein samples. 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 Micro BCA Protein Assay is suitable for quantifying protein solutions in 500 x 1ml assays or in >3,300 micro-well assays.