What is the click chemistry?

Click chemistry is a series of reactions proposed by K. Barry Sharpless, the winner of the Nobel Prize in Chemistry in 2001, and its core is to develop a complete set of heteroatom-containing link units based on CXC. The new method of combinatorial chemistry uses a small amount of simple, reliable, and highly selective chemical transformations to obtain a wider range of molecular diversity.

The principle of click chemistry is that under certain environmental conditions (mild, watery), a pair of functional groups react with each other quickly and selectively (“click”). That is to say, two compatible click function groups A and B are activated, and the activated two molecules form a stable coupling body.

Common click chemistry reaction

Since click chemistry was proposed in 2001, click chemistry has been widely used in many fields such as synthetic chemistry, biological targets, drug design, ADMET, enzymology research, genomics, proteomics, and immunology.

The secondary structure of proteins, especially α-helix and β-sheet, is the key to biological interaction. Using click chemistry to make the five-membered heterocycle formed by the azide and alkynyl or cyano group on the side chain of the unnatural amino acid can be To achieve the purpose of stabilizing this type of secondary structure in the polypeptide, thereby improving its biological activity, for example, after optimization by molecular simulation, this type of heterocyclic structure has been successfully applied to the biomolecule cJun (a type of α-helix in the transcription process). Source dimer) and antimicrobial peptides.

Activity-Based Protein Profiling (ABPP) is one of the main methods to study the structure and function of important drug target proteins. It is a new technology that uses active site-oriented probes to study the structure and function of proteins. A relatively simple and clear method is used to study the complex interactions between active small molecules and biological macromolecules at the molecular and cellular levels, so as to reveal the key regulatory mechanisms of organisms under physiological or pathological conditions from the molecular level. Cravatt and his collaborators link the active site-directed probe to the protein through click chemistry, enabling real-time observation of protein activity changes in the cell environment in real time.

Click chemistry can be divided into two categories:

1.Types of copper-catalyzed reactions

Copper(I)-catalyzed Azide-Alkyne Click Chemistry reaction (CuAAC)


1)Small azides and alkynes have excellent substrate properties
2)Optimal optimization of test applicable conditions (type & copper source, reducing agent, and copper ligand)
3)Suitable for experiments that do not interfere with copper toxicity (not recommended for in vivo or live-cell labeling)
4)The reaction rate is the slowest (compared to the other two reactions)

2.No copper reaction type

Force-induced azide-alkynyl coupling reaction (Strain-promoted Azide-Alkyne Click Chemistry reaction, SPAAC)


1)The detection of small molecule azides is faster than CuAAC
2)No need for copper ions, non-toxic
3)There are no catalysts or ligands, so no extensive condition optimization is required

Tetrazine-trans- Cyclooctene Ligation (TCO)

Click on chemical features

1)Quick click chemical reaction, suitable for in vivo cell labeling and low concentration reaction.
2)No need for copper ions, non-toxic