Test for proteins : (i) Take 2-3 ml solution of protein in a test tube. Add 1 ml of cone. HN03 in it. A white ppt. is formed.
(ii) Heat test tube in a spirit lamp, white ppt. changes to yellow and solution becomes yellow coloured. Yellow colour turns orange by addition of alkali. The presence of benzene ring is responsible for yellow colour in test. Aromatic | amino acids like tryptophan and tyrosine, are j responsible for this test.
(B)Test for proteins, fats, oils, amino acids : Take j the animal or plant tissue extract and grind it in trichloro acetic add using -a mortar and pestle, i Strain the slurry through a cotton cloth. We get 2 fractions:
(i) Filtrate : It has micromolecules.
(ii) Retentate: It has macromolecules like proteins, nucleic add etc