It is based on the biuret reagent, a blue solution that turns violet upon contact with proteins, or any substance with peptide bonds. The test and reagent do not actually contain biuret; they are so named because both biuret and proteins have the same response to the test.
Considering this, what is the principle of the biuret test?
The biuret test (Piotrowski's test) is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms violet-colored coordination complexes in an alkaline solution. Several variants on the test have been developed, such as the BCA test and the Modified Lowry test.
What does a positive biuret test indicate?
Biuret reagent, made of sodium hydroxide and copper (II) sulfate, is used for determining the presence of protein in a sample. The test relies on the reaction between copper ions and peptide bonds in an alkaline solution. A violet color indicates the presence of proteins.
How do you test for protein biology?
The Biuret Test is done to show the presence of peptide bonds, which are the basis for the formation of proteins. These bonds will make the blue Biuret reagent turn purple. add an equal amount of NaOH to a solution of the food, mix carefully. add a few drops of 1% CuSO4, do not shake the mixture.