Proteins & Peptides
The fundamental component of a protein is the polypeptide chain composed of amino acid residues; twenty different residues are involved in protein synthesis. These residues might be modified after the synthesis of the polypeptide chain. The other components of proteins are called prosthetic groups.The structure of the amino acids and their characteristic property as amphoteric molecules is described, followed by a description of asymmetry and chirality.The way in which amino acid residues interact within proteins is explained.The ionic properties of proteins are important in such interactions and in their electrophoretic separation. Proteins can also be separated on the basis of their size. After mentioning how the order of the amino acid residues in polypeptides can be determined, the hierarchies of protein structure are briefly described.The tertiary structure of proteins can be destroyed by denaturation. Finally, it is shown that even small peptides can possess biological activity, for example as hormones and transmitters.