Proteins Test Flashcards
(12 cards)
List the specific tests for amino acids
MANSH X
Xanthoprotein Hopkins cole Millons reaction Sakaguchi reaction Nitropruside test Absorption test
Xanthoprotein test
For aromatic amino acids (tryptophan, tyrosine, phenylalanine)
Colour change
Hopkins Cole test
Tryptophan
Purple colour
Million’s reaction
Tyrosine and other phenolic compounds
Red colour
Sakaguchi reaction
Arginine
Red colour
Nitropruside test
Sulphur containing amino acids (cysteine & methionine)
Red/violet colour
Absorption test
Aromatic amino acids absorb maximally at 280nm (UV range) due to the aromatic ring
List the general tests for amino acid/proteins
Ninhydrin test
Bluret test
Ninhydrin test
For the amino group
Blue/Violet colour
Bluret test
Tripeptides, polypeptides & proteins (only positive if there are at least 2 peptide bonds in the protein or peptide). It is negative for amino acids and dipeptides
Purple color
List 4 agents used to precipitate protein in the lab
10% trichloroacetic acid -TCA
0.33M H2SO4
Ammonium sulphate solution (NH4)2SO4
5% sodium tungstate
What is the test for ketone bodies (acetoacetic acid)
Na nitroprusside - Rothera’s test
Purple colour at interface
