Elementary plant Biochemistry and Biotechnology (2+1)

Primary structure

 
• Primary structure of protein refers to the number of amino acids and the order in which they are covalently linked together.
• It also refers to the location of disulfide bridges, if there are any, in a polypeptide chain.
• The peptide bond is covalent in nature, quiet stable and referred as backbone of the protein.
  
• They can be disrupted by chemical or enzymatic hydrolysis but are not directly influenced by salt, concentration, change in pH or solvent.
• Frederick Sanger in 1953 determined the complete amino acid sequence of insulin for the first time.

The important steps involved in determining the primary structure of protein are

• Determination of number of (chemically different) polypeptide chains or subunits in the protein. Separation of polypeptide chains if more than one are present in a protein.
• Determination of the amino acid sequence of the subunits.
  
• Elucidation of the position of the disulfide bonds, if any, between and within the subunits