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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.
a test for the determination of serum proteins, based on the reaction of an alkaline copper reagent with substances containing two or more peptide bonds to produce a violet-blue color.
Etymology: L, bis + Gk, ouron, urine
a method for detecting proteins in serum. In alkaline solution, copper sulfate ions react with the peptide bonds of proteins to produce a pink to purple color, called the biuret reaction. The amount of serum protein in a sample solution is estimated by comparing its color with that of a standard solution whose protein concentration is known.
biuret testA colourimetric urine test for identifying peptides and proteins using the biuret reagent (sodium hydroxide and copper sulfate).
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.