Biuret Reaction

**Biuret reaction (B.r.)**

Method of qualitative and quantitative determination of **proteins** and products of **partial hydrolysis** in **blood**, urine and other **liquids**, consisting of **detection and colorimetry** of violet, blue or reddish coloring , appearing against the background of the reagent “K **sulfuric acid with copper sulfate**”.

When the protein part of the substance interacts with CuSO42H2O, the hydrogen of sulfuric acid reacts with the nitro groups SH of amino acid residues

The biuret reaction is a method for the detection and quantitative expression of proteins. It is mainly used to determine the protein content in blood serum and other biological fluids.

The essence of the method is to perform the following chemical reaction:

Peptones → Peptoxin → Guanine → Biuret + water + nitrogen (gas), etc. → Formation of a blue-violet solution.