Quenched fluorescent peptides

Fluorescence Resonance Energy Transfer is a method that allows the detection of a ‘distance-dependent’ interaction between the excited states of two distinct, dye-linked, molecules, i.e. the ‘fluorophore’ and the ‘quencher’. Quenched fluorescent peptides (‘FRET peptides’) are widely used as suitable substrates in enzyme studies.

Their synthesis requires that the peptide is conjugated with both a fluorophore and a quencher dye. ‘Fluorescence/quencher’ pairs do require distinct overlap between the fluorescence emission spectrum of the fluorophore and the UV-absorbance spectrum of the quencher. So, when the fluorophore and quencher are conjugated to one and the same peptide, with a limited distance, the quencher efficiently blocks the emission of the fluorophore. However, when a peptide bond is cleaved, e.g. by enzymatic degradation, the distance between fluorophore and quencher is suddently increased significantly, and as a result of this the fluorophore is activated. The fluorescence signal can be detected continuously, allowing quantification of the enzyme activity.

Frequently used fluorophore/quencher combinations are

Fluorophore Quencher Excitation wavelength Emission wavelength
Abz
2-Aminobenzoyl
Dnp
2,4-dinitrophenyl
320 nm 420 nm
EDANS
5-[(2-Aminoethyl)amino]
naphthalene-1-sulfonic acid
Dabcyl
4-([4′-dimethylamino)phenyl]
azo)benzoyl
340 nm 490 nm
Mca
7-Methoxycoumarin-4-yl)acetyl
Dnp
2,4-dinitrophenyl
325 nm 392 nm
Trp
Tryptophan
Dnp
2,4-dinitrophenyl
280 nm 360 nm
FAM
Carboxyfluorescein
Dabcyl
4-([4′-dimethylamino)phenyl]
azo)benzoyl
492 nm 517 nm
Abz – Dnp

Abz – Dnp

EDANS – Dabcyl

EDANS – Dabcyl

Mca – Dnp

Mca – Dnp

Tryptophan – Dnp

Tryptophan – Dnp

FAM – Dabcyl

FAM – Dabcyl

We use cookies to ensure that we give you the best experience on our website. We also use cookies to ensure we show you advertising that is relevant to you. If you continue without changing your settings, we’ll assume that you are happy to receive all cookies on the Pepscan website. However, if you would like to, you can change your cookie settings at any time in your browser.
Cookie Policy
Find out more
Accept All Cookies
By continuing to browse or by clicking "Accept All Cookies" you agree to the storing of first and third-party cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.
Cookie Policy
Cookie Settings
Accept All Cookies