The Types of Peptide Modifications and Peptide Library

1. The Types of Peptide Modifications and Peptide Library Peptides are molecules of biological origin that shows various activities and have diverse functions in organisms. The incorporation of peptide modifications may have various purposes such as improving activity, tracking the peptide in the biological system under study, etc. A large variety of peptide modifications are available which are usually classified on the basis of chemical structure or chemical site of modification (Figure 1). The peptide modifications include N-terminal modification, C-terminal modification, amino acid side chain modification, amino acid modification. -carbone modification and backbone Figure 1. Peptide modifications chart. The modifications of the peptide backbone chain or of the individual amino acids have notable effects on the physical and chemical properties of the peptide overall. It may affect the hydrophobicity and thus it can enhance water-solubility. Figure 2. Peptide modifications have significant effect on peptide behavior. It may have significant effect on the biological properties as well. Peptide modifications may improve the resistance to degradation within the body, expand the biological distribution, or increase the specific activity. Modified peptides are widely used in the research of peptide drugs, immunology, diagnostics, biocatalysis, modified antibodies and peptide reagents.

2. Other types of peptides modifications involve conjugation to proteins or labeling with heavy isotopes, biotin, flurophores, and chromophores. A large choice of peptide modifications is available from Genosphere Biotechnologies and feasibility is dependent on the peptide sequence, properties and desired location. Hence, Genosphere Biotechnologies peptide synthesis team will review each request. Peptide modifications: Unusual and unnatural amino acids The incorporation of unusual or unnatural amino acids into a peptide sequence may improve the stability or the functionality of a target sequence. Other modifications are required to closely mimic in vivo molecules through post-translational modifications such as the acetylation of lysine (N-acetyl Lysine ) and hydroxylation of proline (hydroxyproline). Unnatural amino acid with disubstituted substituted monomers such as N-methyl amino acids are attracting a lot of interest to improve bioavaibility. Many unusual, naturally occuring amino acids (Table 1) are available from Genosphere Biotechnologies including citrulline (Cit), hydroxyproline (Hyp), norleucine (Nle), ornithine (Orn), α-aminobutyric acid (Abu), methionine sulfoxide (Met-SO). -carbons or N- Table 1. Examples of unusual amino acids available for incorporation into peptides. Peptide library Synthetic peptide library is a collection of peptides that are chemically synthesized. Using a specific set of rules to generate the sequence, instead of relying on using phage or biological systems. At least five subtypes of synthetic peptide libraries have been developed over the years. They all differ from each other by the set of rules used to generate the sequences in realtion to the reasearch task at hand. These are (i) overlapping peptide library, (ii) truncation peptide library, (iii) random peptide library, (iv) alanine scanning v and (v) positional or scrambled peptide library. Genosphere Biotechnologies Address: 52 rue du Moulin de Pierre,92140 Clamart,FRANCE Tel: +33 - 142 717 021 Fax: +33 - 142 717 023 Email: info@genosphere-biotech.com Website: https://www.genosphere-biotech.com/