Fluorescent Labeling Reagents HEADING_TITLE

 

Fluorescent labeling reagents are used to attach a fluorescent group to peptides, proteins and other biomolecules.  The resulting fluorescently labeled products can be accurately detected in very low concentrations.  Fluorescent labeled substrates are very useful in studying substrate receptor binding,  identifying unknown receptors or identifying receptor substrates.  A significant application of fluorescence-labeled compounds is fluorescence microscopy to study the location of receptors in living cells.
Fluorescence
Fluorescent groups, or fluorophores, absorb light at a certain wavelength and reemit light at a longer wavelength.  A fluorescent molecule absorbs a photon of light putting an electron into a higher energy level.  Some of the energy is dispersed through collisions and molecular vibrations, then the energy is emitted as a photon of light at a longer wavelength.
Fluorescent compounds are characterized by two spectra, the absorbance or excitation spectrum and the emission spectrum.  The difference between the maximum of the excitation spectrum and the maximum of the emission spectrum is the Stokes shift.  Generally, if the Stokes shift is large, the fluorescence can be more accurately measured than if the Stokes shift is very small.
FRET
FRET, which is an abbreviation of fluorescence resonance energy transfer or Förester resonance energy transfer, occurs when the energy from an excited fluorophore is transferred by non-radiative interactions to a nearby energy-absorbing group.  This results in quenching of the fluorophore.  If the energy-absorbing group is moved farther away, the fluorescence of the fluorophore returns.
Since FRET is effective only at distances up to tens of nonometers, FRET is very useful for studying protein conformation changes and substrate binding to receptors.  It also affords a highly sensitive means of studying the kinetics of peptidases.
For efficient energy transfer to occur, there must be significant overlap of the emission spectrum of the fluorophore, or donating group and the absorption spectrum of the energy-absorbing or acceptor group. 

Fluorescent labeling reagents are used to attach a fluorescent group to peptides, proteins and other biomolecules.  The resulting fluorescently labeled products can be accurately detected in very low concentrations.  Fluorescent labeled substrates are very useful in studying substrate receptor binding,  identifying unknown receptors or identifying receptor substrates.  A significant application of fluorescence-labeled compounds is fluorescence microscopy to study the location of receptors in living cells.


Fluorescence


Fluorescent groups, or fluorophores, absorb light at a certain wavelength and reemit light at a longer wavelength.  A fluorescent molecule absorbs a photon of light putting an electron into a higher energy level.  Some of the energy is dispersed through collisions and molecular vibrations, then the energy is emitted as a photon of light at a longer wavelength.

fluorescence diagram

 

Fluorescent compounds are characterized by two spectra, the absorbance or excitation spectrum and the emission spectrum.  The difference between the maximum of the excitation spectrum and the maximum of the emission spectrum is the Stokes shift.  Generally, if the Stokes shift is large, the fluorescence can be more accurately measured than if the Stokes shift is very small.

Stokes Shift


FRET (Fluorescence Resonance Energy Transfer)


FRET, which is an abbreviation of fluorescence resonance energy transfer or Förster resonance energy transfer, occurs when the energy from an excited fluorophore is transferred by non-radiative interactions to a nearby energy-absorbing group.  This results in quenching of the fluorophore.  If the energy-absorbing group is moved farther away, the fluorescence of the fluorophore returns.


Since FRET is effective only at distances up to tens of nonometers, FRET is very useful for studying protein conformation changes and substrate binding to receptors.  It also affords a highly sensitive means of studying the kinetics of peptidases.


For efficient energy transfer to occur, there must be significant overlap of the emission spectrum of the fluorophore, or donating group and the absorption spectrum of the energy-absorbing or acceptor group. 

 

AAPPTec Fluorescent Labeling Reagents

AAPPTec offers these fluorescent labeling reagents and many others at highly compeptitive prices.

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