Description
The BCA Protein Assay is one of the most commonly used methods for protein quantification. Under alkaline condition, the reduction of Cu2+ to Cu+ is realized by peptide bonds in proteins (biuret reaction). The amount of reduced copper is directly proportional to the amount of total proteins. Bicinchoninic acid (BCA) is a chromogenic reagent that chelates the reduced copper, producing a stable purple complex. Compared to Bradford assay, BCA protein assay is more objective, chromogenic reaction can occur on general peptide bonds. It is compatible with high concentration of SDS (5%), Triton X-100 (5%), NP 40 (5%), CHAPS (5%), Tween 20, 60, 80 (5%). Some reagents, including reducing agents, chelating agents (EDTA, EGTA) and high-concentration buffers, interfere with the reactions. However, these interferences can be eliminated by diluting the protein samples