5. Antibodies Gamma globulins present in blood. 6. Blood protein Albumms, haemoglobin and fibrinogen.
Haemoglobin is a globular protein. Its prosthetic group is heme. It Contains 574 amino acid units distributed in four polypeptide chains.
Two chains containing 141 amino acid residues each are called α-chains and the two chains containing 146 amino acid residues are called β-chains.
Sickle cell anaemia is caused by defective haemoglobin obtained by replacing only one amino acid, i. e., glutamic acid by valine.
Denaturation of Proteins
The process that changes the three dimensional structure of native proteins is called denaturation of proteins. It can be caused by Change in pH, addition of electrolyte, heating or addition of solvent like water, alcohol or acetone.
Tests of Proteins( i) Biuret Test Protein solution + NaOH + dil. CuSO4 → pink or violet colour.
( ii) Millon’ s Test Protein solution + Millon ‟ s reagent → pink colour
Millon’ s reagent is solution of mercuric nitrate and nitrite in nitric acid containing traces of nitrous acid.
( iii) Iodine reaction Protein solution + iodine in potassium iodide solution → yellow colour.