BCA Protein Quantification Kit is one of the most sensitive methods for measuring protein concentration. The protein reduces Cu2 ⁺ to Cu ⁺ under alkaline conditions. Then, Cu ⁺ interacts with the unique BCA Reagent A (containing BCA) to preform a sensitive color reaction, forming coordination complexes. The water-soluble complex has strong absorbance at A562 nm. Its absorbance and protein concentration have a good linear relationship in a wide range, and the protein concentration can be calculated according to the absorbance value. Therefore, the concentration of the protein to be tested can be calculated by measuring its absorption value at A562 nm using a microplate reader and comparing it with the standard curve.
Common concentrations of detergents (SDS, Triton X-100, Tween-20, etc.) do not affect the detection results, but they are affected by chelating agents (EDTA, EGTA), reducing agents (DTT, mercaptoethanol) and lipids. In the experiment, if sample dilution or lysis solution with high background values, it is recommended to use Bradford protein assay.