What are the functions of the components of Biuret dye?

Question

Biuret dye is used in protein content determination

Answer 1

Biuret reagent only contains three ingredients dissolved in water.

The Copper (II) sulfate (CuSO4) is the source for the Copper (II) ions needed.

The Potassium sodium tartrate (KNaC4H4O6) is often added to stabilize the Copper ion complex.

The Potassium hydroxide (KOH) or Sodium hydroxide (NaOH) does not react, but does provide the basic medium for the reaction to take place.

The protein or polypeptide being analyzed provides the material to form the Biuret (H2N-CO-NH-CO-NH2) like structure which produces the colored complex and gives the solution its name.