Peptide Synthesis

Peptide Synthesis: An Overview

What is Peptide Synthesis?

Peptide synthesis is the process of creating peptides, which are chains of amino acids linked by peptide bonds. This process is crucial in the fields of biochemistry and molecular biology for research and therapeutic purposes. Peptides are synthesized by forming bonds between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water – a reaction known as a condensation reaction.

Types of Peptide Synthesis

There are two primary methods used for synthesizing peptides:

  1. Solid Phase Peptide Synthesis (SPPS):

    • Introduction: Developed by Robert Bruce Merrifield in 1963, SPPS is now the most common method for synthesizing peptides and proteins. This technique involves attaching the C-terminal end of the first amino acid to a solid support (resin), and amino acids are added one at a time in a repetitive cycle of deprotection, coupling, and washing.
    • Advantages: SPPS allows for the rapid synthesis of peptides and easy purification. It also enables the incorporation of unnatural amino acids and modifications that are otherwise difficult to achieve in solution.
    • Process: The peptide remains bound to the resin throughout the synthesis, and upon completion, it is cleaved off to yield the desired product.

  2. Liquid Phase Peptide Synthesis (LPPS):

    • Introduction: This traditional method involves synthesizing peptides in solution, which is more straightforward than SPPS but can become cumbersome as the peptide chain lengthens.
    • Advantages: LPPS can be advantageous for synthesizing very short peptides or when specific synthesis conditions could damage the solid support used in SPPS.
    • Process: Amino acids are coupled in solution, and the product must be isolated and purified after each step, making the process labor-intensive for longer peptides.

Peptide Synthesis Steps

The general steps in peptide synthesis, particularly in SPPS, include:

  1. Coupling: The amino group of the incoming amino acid is activated to form a bond with the carboxyl group of the resin-bound amino acid.
  2. Deprotection: The protecting group on the amino end of the resin-bound amino acid is removed to allow the next amino acid to attach.
  3. Cleavage: Once the peptide chain is complete, it is cleaved from the resin, typically using a specific chemical cocktail that does not harm the peptide itself.
  4. Purification: The final step involves purifying the peptide using methods like high-performance liquid chromatography (HPLC) to remove any unwanted byproducts and impurities.
  5. Characterization: Techniques such as mass spectrometry and analytical HPLC are used to verify the sequence and purity of the synthesized peptide.

Applications of Synthesized Peptides

Synthetic peptides have a wide range of applications:

  • Therapeutics: Many peptides have therapeutic properties and are used in medications to treat diseases.
  • Vaccines: Short peptides can mimic proteins from pathogens, making them ideal for vaccine development.
  • Research: Synthetic peptides are used as tools in biochemical experiments to probe protein interactions and other cellular processes.
  • Cosmetics: Peptides are used in skincare products for their anti-aging, firming, and smoothing properties.

Conclusion