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trFluor™ Tb-streptavidin conjugate
Streptavidin conjugates are widely used together with a conjugate of biotin for specific detection of a variety of proteins, protein motifs, nucleic acids and other molecules since streptavidin has a very high binding affinity for biotin. This trFluor™ Tb-streptavidin conjugate comprises streptavidin (as the biotin-binding protein) with trFluor™ Tb covalently attached (as the time-resolved green fluorescent terbium label). It is commonly used as a second step reagent for indirect immunofluorescent staining, when used in conjunction with biotinylated primary antibodies. It is a very valuable tool for biotin-streptavidin-based biological assays and tests using TR-FRET platform. A variety of the complementary biotinylated reagents are available from numerous commercial vendors.
<p>Time-resolved fluorescence energy transfer&nbsp;(TR-FRET) is the practical combination of&nbsp;time-resolved fluorometry (TRF)&nbsp;combined with&nbsp;F&ouml;rster resonance energy transfer&nbsp;(FRET) that offers a powerful tool for drug discovery researchers. TR-FRET combines the low&nbsp;background&nbsp;aspect of TRF with the&nbsp;homogeneous assay&nbsp;format of FRET. The resulting assay provides an increase in flexibility, reliability and sensitivity in addition to higher throughput and fewer false positive/false negative results. FRET involves two&nbsp;fluorophores, a donor (such as trFluor Eu and trFluor Tb) and an acceptor.&nbsp;Excitation of the donor by an energy source (e.g. flash lamp or laser) produces an energy transfer to the acceptor if the two are within a given proximity to each other. The acceptor in turn emits light at its characteristic wavelength. The FRET aspect of the technology is driven by several factors, including spectral overlap and the proximity of the fluorophores involved, wherein energy transfer occurs only when the distance between the donor and the acceptor is small enough. In practice, FRET systems are characterized by the&nbsp;F&ouml;rster's radius&nbsp;(R<sub>0</sub>): the distance between the fluorophores at which FRET efficiency is 50%. For many FRET parings, R<sub>0</sub>&nbsp;lies between 20 and 90 &Aring;, depending on the acceptor used and the spatial arrangements of the fluorophores within the assay.&nbsp;Through measurement of this energy transfer, interactions between&nbsp;biomolecules&nbsp;can be assessed by coupling each partner with a fluorescent label and detecting the level of energy transfer. Acceptor emission as a measure of energy transfer can be detected without needing to separate bound from unbound assay components (e.g. a filtration or wash step) resulting in reduced assay time and cost.</p>
<p>Time-resolved fluorescence energy transfer&nbsp;(TR-FRET) is the practical combination of&nbsp;time-resolved fluorometry (TRF)&nbsp;combined with&nbsp;F&ouml;rster resonance energy transfer&nbsp;(FRET) that offers a powerful tool for drug discovery researchers. TR-FRET combines the low&nbsp;background&nbsp;aspect of TRF with the&nbsp;homogeneous assay&nbsp;format of FRET. The resulting assay provides an increase in flexibility, reliability and sensitivity in addition to higher throughput and fewer false positive/false negative results. FRET involves two&nbsp;fluorophores, a donor (such as trFluor Eu and trFluor Tb) and an acceptor.&nbsp;Excitation of the donor by an energy source (e.g. flash lamp or laser) produces an energy transfer to the acceptor if the two are within a given proximity to each other. The acceptor in turn emits light at its characteristic wavelength. The FRET aspect of the technology is driven by several factors, including spectral overlap and the proximity of the fluorophores involved, wherein energy transfer occurs only when the distance between the donor and the acceptor is small enough. In practice, FRET systems are characterized by the&nbsp;F&ouml;rster's radius&nbsp;(R<sub>0</sub>): the distance between the fluorophores at which FRET efficiency is 50%. For many FRET parings, R<sub>0</sub>&nbsp;lies between 20 and 90 &Aring;, depending on the acceptor used and the spatial arrangements of the fluorophores within the assay.&nbsp;Through measurement of this energy transfer, interactions between&nbsp;biomolecules&nbsp;can be assessed by coupling each partner with a fluorescent label and detecting the level of energy transfer. Acceptor emission as a measure of energy transfer can be detected without needing to separate bound from unbound assay components (e.g. a filtration or wash step) resulting in reduced assay time and cost.</p>
CatalogSize
Price
Quantity
16926100 ug
Price
 
Physical properties

Molecular weight~52000
SolventWater
Spectral properties

Correction factor (260 nm)0.942
Correction factor (280 nm)0.797
Excitation (nm)333
Emission (nm)544
Storage, safety and handling

H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22
StorageFreeze (< -15 °C); Minimize light exposure
UNSPSC12352200
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Page updated on October 8, 2025