Qualitative Test for Proteins Flashcards
Alpha amino acids (All amino acids having -NH2 except proline and hydroxyproline)
Ninhydrin test
Peptide bonds (All protein with at least 2 peptide bonds NOT amino acids)
Biuret test
Tyrosine (Phenolic group)
Millon’s test
Tryptophan (Indole group)
Hopkin’s-Cole Test
Benzene ring of aromatic amino acids
(Tyrosine and Tryptophan)
Xanthoproteic acid
Amino acids with sulfur group (-SH)
Cystine and Cysteine
Sodium Nitroprusside test/ Mömer Test
Arginine (specifically guanidine group)
Sakaguchi
test
Sulfur-containing amino acid such as
cysteine, cysteine, and methionine
(Sulfur group)
Lead acetate
test
Reagent: Ninhydrin reagent
Result: Violet
Ninhydrin test
Reagent: NaOH, Copper sulfate, Potassium sodium tartrate
Result: Violet
Biuret test
Reagent: Metallic Mercury in Nitric Acid
Result: Red
Millon’s test
Reagent: Glycolic acid and Sulfuric acid
Result: Violet Ring
Hopkin’s-Cole
Test
Reagent: Conc. Nitric acid
and 40% NaOH
Result: Yellow to orange color
Xanthoproteic
acid
Reagent: 5% Sodium
nitroprusside, NH4OH
Result: Deep Purple/ Red color
Sodium
Nitroprusside
test/ Mömer
Test
Reagent: 40% NaOH,
ethanolic a-naphthol and
bromine water
Result: Red color
Sakaguchi
test
