Peptide Synthesis Technologies	    
	    Introduction  
	      Proteins are present in every living cell and possess a variety of  biochemical activities. They appear as enzymes, hormones, antibiotics, and  receptors. They compose a major portion of muscle, hair, and skin.  Consequently, scientists have been very interested in synthesizing them in the  laboratory. This interest has developed into a major synthetic field known as  Peptide Synthesis. The major objectives in this field are four-fold: 
	    1. To verify the structure of naturally  occurring peptides as determined by degradation techniques. 
2. To study the relationship between  structure and activity of biologically active protein and peptides and  establish their molecular      mechanisms. 
3. To synthesize peptides that are of  medical importance such as hormones and vaccines.
4. To develop new peptide-based  immunogens. 
Solid Phase Peptide  Synthesis (SPPS)  
  The fundamental premise of this technique involves the incorporation of N-a-amino acids into a  peptide of any desired sequence with one end of the sequence remaining attached  to a solid support matrix. While the peptide is being synthesized usually by  stepwise methods, all soluble reagents can be removed from the peptide-solid  support matrix by filtration and washed away at the end of each coupling step.  After the desired sequence of amino acids has been obtained, the peptide can be  removed from the polymeric support. 
  
  The general scheme for solid phase peptide synthesis is outlined in Figure  1. The solid support is a synthetic polymer that bears reactive groups such as  -OH. These groups are made so that they can react easily with the carboxyl  group of an N-a-protected amino acid, thereby covalently binding it to the polymer. The  amino protecting group (X) can then be removed and a second N-a-protected amino  acid can be coupled to the attached amino acid. These steps are repeated until  the desired sequence is obtained. At the end of the synthesis, a different  reagent is applied to cleave the bond between the C-terminal amino acid and the  polymer support; the peptide then goes into solution and can be obtained from  the solution.