Amino acids are the essential constituents of all living cells. They are the building blocks of proteins. Chemically, amino acids are nitrogenous compounds having both-an acidic carboxyl (-COOH) group and a basic amino (-NH,) group. The general structural formula of the amino acids is : side chain common to all a-amino acids Glycine is considered as the simplest amino acid as it has one amino group, one carboxylic group and no substituent functional group.