What is the name of reagent used in protein test?

The commonly used reagent in the protein test is Biuret reagent. Biuret reagent is a solution of sodium hydroxide (NaOH) and copper sulfate (CuSO4). It is used to detect the presence of peptide bonds, which are the chemical bonds that link amino acids together to form proteins. When Biuret reagent is added to a solution containing proteins, the copper ions in the reagent bind to the peptide bonds and form a colored complex. The color of the complex depends on the concentration of proteins in the solution. A purple color indicates a high protein concentration, while a blue color indicates a low protein concentration.