· Truncation Peptide Library:
      Peptides can be cleaved systematically into small fragments. The library of truncated peptides could then be used to predict the minimum length amino acid that could be used to achieve optimal epitope activity.

· Random Peptide Library:
      Selected positions are substituted with all 20 natural amino acids simultaneously, which might increase peptide activity.

· Positional Peptide Library:
      Selected sites or regions within a peptide sequence are replaced systematically with other amino acids. These libraries facilitate the identification of the positions and regions that are responsible for specific activities or effects.

· Alanine Peptide Scanning Library:
      Each amino acid is substituted individually and systematically for alanine. Alanine scanning allows the easy identification of the specific amino acids that are responsible for the conformation, activity, and function of a protein.

·Scrambled Peptide Library:
      These libraries are designed using variations of the original sequence of a peptide. The resulting peptides are used generally as negative controls to show that a specific sequence is critical to the protein function or activity. It is also a random screening tool used to find new leads.

· Overlapping Peptide Library:
      Individual peptides can be divided in to several fragments that overlap. The resulting overlapping peptide libraries can then be used for processes including continuous and linear epitope mapping.