EXPERIMENT 1B Flashcards
General test for proteins except proline (yellow); Test for the –NH2 group in free amino acid
Ninhydrin Test
Reagent for Ninhydrin Test
Ninhydrin
Positive Result for Ninhydrin Test
a deep blue or purple color solution
Chemical Reaction for Ninhydrin Test
Ninhydrin oxidizes the amino group in the amino acid and proceeds the chemical reaction forming a complex called Ruhemann’s complex which give the deep blue color.
Specific test for indole group, tryptophan
Hopkins-Cole Test
Reagent for Hopkins-Cole Test
Hopkin’s Cole reagent and conc. H2SO4
Positive Result for Hopkins-Cole Test
purple ring at the interface of two liquids
Chemical Reaction for Hopkins-Cole Test
The indole group of tryptophan reacts with glyoxylic acid in the presence of concentrated H2S04 to give a purple color.
Biochemical test for activated aromatic rings, Tyrosine and tryptophan
Xanthoproteic Test
Reagents for Xanthoproteic Test
Conc. Nitric Acid, ammonium hydroxide
Positive Result for Xanthoproteic Test
Yellow or dark orange solution or precipitate
Chemical Reaction for Xanthoproteic Test
- When the sample is treated with a concentrated nitric acid it undergoes nitration with the aromatic amino acids such as tyrosine and tryptophan and forms a yellow colored
- Phenylalanine is not an activated benzene ring so it will not react
Test for guanidine group, arginine
Sakaguchi Test
Reagents for Sakaguchi Test
α-Naphthol and a drop of
sodium hypobromite
Positive Result for Sakaguchi Test
red-colored complex solution
