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a urea derivative; its presence is detected after addition of sodium hydroxide and copper sulfate solutions by a pinkish-violet color (protein test) or a pink and finally a bluish color (urea test).
biuret reaction the reaction in biuret tests.
biuret test either of the tests done with biuret.
the formation of biuret that gives a violet color as a result of the reaction of a polypeptide of more than three aminoacyl residues with CuSO4 in strongly alkaline solution; dipeptides and amino acids (except histidine, serine, and threonine) do not so react; used for the detection and quantification of polypeptides, or proteins, in biologic fluids.
bi·u·ret re·ac·tion, biuret test (bī'yŭr-et' rē-ak'shŭn, bī'yŭr-et' test)
The formation of biuret, which gives a violet color because of the reaction of a polypeptide of more than three amino acids with CuSO4 in strongly alkaline solution; used for the detection and quantitation of polypeptides or protein in biologic fluids.