trFluor™ Eu-streptavidin conjugate

Time-resolved fluorescence energy transfer (TR-FRET) is the practical combination of time-resolved fluorometry (TRF) combined with Förster resonance energy transfer (FRET) that offers a powerful tool for drug discovery researchers. TR-FRET combines the low background aspect of TRF with the homogeneous assay 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 fluorophores, a donor (such as trFluor Eu and trFluor Tb) and an acceptor. 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 Förster's radius (R<sub>0</sub>): the distance between the fluorophores at which FRET efficiency is 50%. For many FRET parings, R<sub>0</sub> lies between 20 and 90 Å, depending on the acceptor used and the spatial arrangements of the fluorophores within the assay. Through measurement of this energy transfer, interactions between biomolecules 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.

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Telephone	1-800-990-8053
Fax	1-800-609-2943
Email	sales@aatbio.com
Quotation	Request
International	See distributors
Shipping	Standard overnight for United States, inquire for international

Physical properties

Molecular weight	~52000
Solvent	Water

Spectral properties

Correction Factor (260 nm)	0.911
Correction Factor (280 nm)	0.777
Excitation (nm)	346
Emission (nm)	617

Storage, safety and handling

Certificate of Origin	Download PDF
H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Freeze (< -15 °C); Minimize light exposure
UNSPSC	12352200

Overview SDS Protocol

Molecular weight

~52000

Correction Factor (260 nm)

0.911

Correction Factor (280 nm)

0.777

Excitation (nm)

346

Emission (nm)

617

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™ Eu-streptavidin conjugate comprises streptavidin (as the biotin-binding protein) with trFluor™ Eu covalently attached (as the time-resolved red fluorescent europium 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.

Spectrum

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Spectral properties

Correction Factor (260 nm)	0.911
Correction Factor (280 nm)	0.777
Excitation (nm)	346
Emission (nm)	617

Product Family

Name	Excitation (nm)	Emission (nm)	Correction Factor (260 nm)	Correction Factor (280 nm)
trFluor™ Tb-streptavidin conjugate	333	544	0.942	0.797

Images

Figure 1. Time-resolved fluorescence energy transfer (TR-FRET) is the practical combination of time-resolved fluorometry (TRF) combined with Förster resonance energy transfer (FRET) that offers a powerful tool for drug discovery researchers. TR-FRET combines the low background aspect of TRF with the homogeneous assay 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 fluorophores, a donor (such as trFluor Eu and trFluor Tb) and an acceptor. 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 Förster's radius (R₀): the distance between the fluorophores at which FRET efficiency is 50%. For many FRET parings, R₀ lies between 20 and 90 Å, depending on the acceptor used and the spatial arrangements of the fluorophores within the assay. Through measurement of this energy transfer, interactions between biomolecules 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.

Citations

View all 1 citations: Citation Explorer

Overexpression of MACC1 and the association with hepatocyte growth factor/c-Met in epithelial ovarian cancer
Authors: Li, Hongyu and Zhang, Hui and Zhao, Shujun and Shi, Yun and Yao, Junge and Zhang, Yanyan and Guo, Huanhuan and Liu, Xingsuo
Journal: Oncology letters (2015): 1989--1996

References

View all 47 references: Citation Explorer

A streptavidin paramagnetic-particle based competition assay for the evaluation of the optical selectivity of quadruplex nucleic acid fluorescent probes
Authors: Largy E, Hamon F, Teulade-Fichou MP.
Journal: Methods. (2012)

Biotin-4-fluorescein based fluorescence quenching assay for determination of biotin binding capacity of streptavidin conjugated quantum dots
Authors: Mittal R, Bruchez MP.
Journal: Bioconjug Chem (2011): 362

Iminobiotin binding induces large fluorescent enhancements in avidin and streptavidin fluorescent conjugates and exhibits diverging pH-dependent binding affinities
Authors: Raphael MP, Rappole CA, Kurihara LK, Christodoulides JA, Qadri SN, Byers JM.
Journal: J Fluoresc (2011): 647

Streptavidin-Binding Peptide (SBP)-tagged SMC2 allows single-step affinity fluorescence, blotting or purification of the condensin complex
Authors: Kim JH, Chang TM, Graham AN, Choo KH, Kalitsis P, Hudson DF.
Journal: BMC Biochem (2010): 50

Determination of 17beta-oestradiol by fluorescence immunoassay with streptavidin-conjugated quantum dots as label
Authors: Sun M, Du L, Gao S, Bao Y, Wang S.
Journal: Steroids (2010): 400

Multimodality nuclear and fluorescence tumor imaging in mice using a streptavidin nanoparticle
Authors: Liang M, Liu X, Cheng D, Liu G, Dou S, Wang Y, Rusckowski M, Hnatowich DJ.
Journal: Bioconjug Chem (2010): 1385

Site-dependent excited-state dynamics of a fluorescent probe bound to avidin and streptavidin
Authors: Furstenberg A, Kel O, Gradinaru J, Ward TR, Emery D, Bollot G, Mareda J, Vauthey E.
Journal: Chemphyschem (2009): 1517

Influence of streptavidin on the absorption and fluorescence properties of cyanine dyes
Authors: Luschtinetz F, Dosche C, Kumke MU.
Journal: Bioconjug Chem (2009): 576

Fluorescent nanoscale detection of biotin-streptavidin interaction using near-field scanning optical microscopy
Authors: Park HK, Gokarna A, Hulme JP, Park HG, Chung BH.
Journal: Nanotechnology (2008): 235103

Application of biotin-4-fluorescein in homogeneous fluorescence assays for avidin, streptavidin, and biotin or biotin derivatives
Authors: Ebner A, Marek M, Kaiser K, Kada G, Hahn CD, Lackner B, Gruber HJ.
Journal: Methods Mol Biol (2008): 73