R-CH-COOH+HOR.NHOHOH-NH2NinydrinReduced ninydrin+3H20NinhydrinViolet-blue condensation productReducedninhydrinBluepurplecomplexOHVOHProlineYellow orange0productOOHHOOH+HN EVIU5ECOIT
2.2 The biuret test[bja'ret]NH2NH2NH2NHNH2Cu2+135~190℃NHHN+NHOH?NH224O114CNH2NH2NH31HNNH尿素紫红色络合物双缩脲00=0=HN<>NHHN<NHCu2+HC-RHC-RR-CHR-CHCu2+'+OH'C=0C=00=0O=C>NH>NHHNKHNKHC-RHC-RR-CHR-CH....-蛋白质等多肽键化合物红紫色络合物
2.2 The biuret test [bjə'ret]
Biuret test is used to detect the presence of peptide bonds in thesample and to test for the presence of proteins orpeptides.Proteinsandpeptides arepolymersof aminoacids.They arechains of amino acids, which are covalently bound to each otherby a covalent bond, called a peptide bond, betweenthe carbonnumber one (C) of one amino acid and nitrogen number two (N2)of adjacent amino acid. The formation of a peptide bond is acondensationreaction.["kju:prik]In an alkaline environment, in the presence of the cupric ion(Cu+2) and in the biuret reagent, the peptide bond can be used toformavioletorpurple-colored complex
Biuret test is used to detect the presence of peptide bonds in the sample and to test for the presence of proteins or peptides. Proteins and peptides are polymers of amino acids. They are chains of amino acids, which are covalently bound to each other by a covalent bond, called a peptide bond, between the carbon number one (C1 ) of one amino acid and nitrogen number two (N2 ) of adjacent amino acid. The formation of a peptide bond is a condensation reaction. In an alkaline environment, in the presence of the cupric ion (Cu+2) and in the biuret reagent, the peptide bond can be used to form a violet or purple-colored complex. [ˈkjuːprɪk]