Summary of protein quantitative methods|zoonbio

This paper summarizes the common methods of protein quantitative determination, including Bradford method, Lowry method and BCA method, and summarizes the advantages and disadvantages of these three methods in the form of tables.

Method	Principle	Sensitivity	Advantage	Shortcoming
Lowry method	In the alkaline solution, the peptide bond of protein is chelated with Cu2 + to form protein copper complex, reducing phenol phosphomolybdate and producing blue compound. The blue depth is linear with the protein concentration.	25-250μg/mL	widely applied	It has poor specificity, many interfering substances (such as Tris buffer, sucrose, ammonium sulfate, mercapto, phenols, citric acid, etc.), and the straight-line relationship of standard curve is not very strict.
Bradford method	Coomassie brilliant blue G-250 combines with protein in a blue color and has an absorption peak at 595nm. It has a linear relationship with protein content in a certain range	1-5μg/mL	The operation is simple and rapid, and the sample consumption is small.	It is easy to be affected by strong alkaline buffer, Triton X-100, SDS and other detergents; the standard curve is slightly non-linear; there are large deviations in the determination of different proteins.
BCA method	BCA method is based on the principle of biuret. Under the basic condition, the protein reduces Cu2 + to Cu +, BCA chelate Cu + is used as the chromogenic agent to produce blue violet and has an absorption peak at 562nm. The unit price of Cu + is dose-dependent with the protein.	0.5-20μg/mL	It is not easy to be interfered by the general concentration of detergent, and has strong anti-interference ability.	It can be affected by chelating agent and high concentration reducing agent.