Biuret reaction

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Biuret reaction A colorimetric reaction that serves as a basis for the qualitative and quantitative determination of proteins. It depends upon the fact that in a strongly alkaline solution, compounds such as tripeptides (see PEPTIDE) and proteins, which have two amide or peptide bonds linked directly or through intermediate carbon atoms, react with copper sulphate to give a violet colour. Dipeptides and most amino acids do not give this reaction.