N/C Terminal Modification

N/C Terminal Modification

So far, there have been many modifications to the backbone, the main purpose of which is to improve the classic water solubility, enhance hybridization affinity and sequence selectivity, improve bioavailability, and expand its applications in the field of molecular biology. There are many ways to modify the backbone of the monomer, including chemically active sites at both ends of the monomer (N-terminal and C-terminal modification).

N-terminal Modifications

  • Acetyl. Cetylation is the most commonly used N-terminal modification method in peptide synthesis. Generally, acetic anhydride is used to acylate the N-terminal to prevent the peptide's N-terminal amino group from being unstable and oxidized.
The structure of PNA by Acetyl modification
  • Biotin. The binding strength of biotin is even close to the covalent bond, and biotin-labeled peptides are commonly used in immunoassays, histocytochemistry and fluorescence-based flow cytometry. Biotin is often attached to the side chain of lysine or the N-terminus, and 6-aminocaproic acid is usually used as a link between the polypeptide and biotin.
The structure of PNA by Biotin modification
  • Thioctic acid. It is an antioxidant and an important cofactor for the mitochondrial enzyme complex.
  • The structure of PNA by Thioctic acid modification
    The structure of PNA by AzidoLysine modification
  • Azide group. Azidohexanoic acid is a simple building block containing an azide group, which can be used to connect to terminal alkynes through a stable amide bond. The short spacer arm adds the smallest mass modified molecule.

C-terminal Modifications

Here are some modification types of special amino acid structure.

  • Lys (Biotin). Biotin modification via Lys side chain amino group.
  • Lys(N3). Azido modification via Lys side chain amino group.
The structure of PNA by Lys (Biotin) modification
The structure of PNA by Lys(N3) modification

Synthesis Method

The successful development and application of the peptide solid-phase synthesis method has brought a revolutionary breakthrough in the chemical synthesis of peptides and greatly improved the efficiency of peptide synthesis. At present, there are more and more methods to modify the structure of polypeptides. People can choose suitable modification methods according to different purposes. Among them, the research of small molecule protecting groups has been relatively mature, and Fmoc is also generally applicable to the protection of amino acids.


  • Optimize performance

    • The introduction of lysine at the C-terminus of PNA can improve the water solubility of PNA.
    • Connecting a polar group to the N-terminal of PNA greatly increases the water solubility.
  • Simple synthesis

    • The N-terminal modified monomer is synthesized through 3 steps of saponification, condensation, and protection, or the C-terminal modified monomer is directly synthesized through condensation.
  • Rich types

    • The types of modifications that can be selected according to different purposes are relatively abundant.
    • Continuous research and development are also required.

We guarantee the feasibility of synthetic modification for our customers, and Creative Peptides is committed to providing you with timely and high-quality deliverables. At the same time, we guarantee to provide you with cost-effective, complete and concise reports.

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