Related Experiment Video
Updated: Jun 2, 2026
09:33
Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Azobenzene photoswitches for biomolecules
Andrew A Beharry1, G Andrew Woolley
1Department of Chemistry, University of Toronto, 80 St. George St. Toronto, ON M5S 3H6, Canada.
Chemical Society Reviews
|April 13, 2011
Summary
Azobenzene photoisomerization, a 75-year-old process, now effectively controls biomolecules. This review details azobenzene photoswitches for functional changes in peptides, proteins, and more.
Area of Science:
- Biochemistry
- Photochemistry
- Molecular Biology
Background:
- Azobenzene photoisomerization is a well-established photochemical process.
- Recent advancements enable its application in biological systems.
- A key challenge is coupling isomerization to significant biomolecular functional changes.
Purpose of the Study:
- To review the properties of azobenzene enabling its use as a photoswitch in biological contexts.
- To summarize strategies for employing azobenzene photoswitches to control biomolecule function.
- To highlight the potential for photocontrol across diverse biomolecules.
Main Methods:
- Literature review of azobenzene photoisomerization in biological systems.
- Analysis of azobenzene properties relevant to biomolecular applications.
- Synthesis of strategies for azobenzene photoswitch integration.
Main Results:
- Azobenzene exhibits key properties suitable for biological photoswitch applications.
- Successful strategies exist for using azobenzene to modulate peptide, protein, nucleic acid, lipid, and carbohydrate function.
- Effective photocontrol of various biomolecules is achievable.
Conclusions:
- Azobenzene is a versatile photoswitch for biological applications.
- Strategies for its use offer broad potential in controlling biomolecular functions.
- Further research can expand the scope of photocontrolled biomolecules.
More Related Videos
Related Concept Videos
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
01:27Photosystem I
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
01:34The Z-Scheme of Electron Transport in Photosynthesis
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
01:22Photosystem II
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...