trFluor™ Eu maleimide europium complex

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Additional ordering information

Telephone	1-800-990-8053
Fax	1-800-609-2943
Email	sales@aatbio.com
International	See distributors
Bulk request	Inquire
Custom size	Inquire
Shipping	Standard overnight for United States, inquire for international

Physical properties

Molecular weight	1116.96
Solvent	DMSO

Spectral properties

Correction Factor (260 nm)	0.911
Correction Factor (280 nm)	0.777
Extinction coefficient (cm ^-1 M ^-1)	21000
Excitation (nm)	298
Emission (nm)	617

Storage, safety and handling

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	12171501

Alternative formats

trFluor™ Eu succinimidyl ester *europium complex*

Overview SDS Protocol

Molecular weight

1116.96

Correction Factor (260 nm)

0.911

Correction Factor (280 nm)

0.777

Extinction coefficient (cm ^-1 M ^-1)

21000

Excitation (nm)

298

Emission (nm)

617

Many biological compounds present in cells, serum or other biological fluids are naturally fluorescent, and thus the use of conventional, prompt fluorophores leads to serious limitations in assay sensitivity due to the high background caused by the autofluorescence of the biological molecules to be assayed. The use of long-lived fluorophores combined with time-resolved detection (a delay between excitation and emission detection) minimizes prompt fluorescence interferences. Our trFluor™ Eu probes enable time-resolved fluorometry (TRF) for the assays that require high sensitivity. These trFluor™ Eu probes have large Stokes shifts and extremely long emission half-lives when compared to more traditional fluorophores such as Alexa Fluor or cyanine dyes. Compared to the other TRF compounds, our trFluor™ Eu probes have relatively high stability, high emission yield and ability to be linked to biomolecules. Moreover, our trFluor™ Eu probes are insensitive to fluorescence quenching when conjugated to biological polymers such as antibodies.

Platform

Fluorescence microplate reader

Excitation	346 nm
Emission	617 nm
Cutoff	370 nm
Recommended plate	Solid black

Example protocol

PREPARATION OF WORKING SOLUTION

Dye labelling solution (7mM)

Add 10 µL DMSO to the vial to make 7 mM dye labeling solution. Note: We recommend preparing fresh dye labelling solution.

SAMPLE EXPERIMENTAL PROTOCOL

Protocol for Labeling Proteins with trFluor™ Eu Maleimide:

Dissolve your thiol-containing protein at concentration 1-10 mg/mL (3-10 mg is the optimal labeling concentration) using PBS buffer (20 mM, pH 7.2).
Mix the trFluor™ Maleimide and protein solution at 20:1 molar ratio of dye/protein, and shake the reaction mixture at room temperature for 2-4 hours in the dark.
Filter the reaction mixture through a protein spin column for 100 µg to 1 mg protein labeling reaction; or purify the conjugate using gel filtration on a properly sized Sephadex G-25 column if the reaction scale is larger than 1 mg.
Collect the desired fractions for your immediate use or freeze dry them for your future use. Note: The trFluor™ conjugate need be used near neutral pH range (6.5 to 7.5). Either acidic or basic pH would reduce its fluorescence intensity.

Protocol for Labeling Small Molecules with trFluor™ Eu Maleimide:

Dissolve trFluor™ Maleimide (10 -15 mg/mL) and your thiol-contain molecule in DMSO at 1:1.2 molar ratio of dye/ thiol-contain molecule.
Stir the reaction mixture at room temperature for 2-4 hours in the dark.
Purify the conjugate using HPLC (ammonium acetate/water and acetonitrile, pH 7.0).
Collect and pool the desired fractions.
Combine and freeze-dry the pooled fractions. Note: The trFluor™ conjugate need be used near neutral pH range (6.5 to 7.5). Either acidic or basic pH would reduce its fluorescence intensity. Note: These protocols can be used as sample protovols. We recommend to modify as per needed.

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of trFluor™ Eu maleimide *europium complex* to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

	0.1 mg	0.5 mg	1 mg	5 mg	10 mg
1 mM	89.529 µL	447.644 µL	895.287 µL	4.476 mL	8.953 mL
5 mM	17.906 µL	89.529 µL	179.057 µL	895.287 µL	1.791 mL
10 mM	8.953 µL	44.764 µL	89.529 µL	447.644 µL	895.287 µL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)		Molecular weight		Volume (Calculate)		Concentration (Calculate)		Moles
	/		=		x		=

Spectrum

Open in Advanced Spectrum Viewer

Spectral properties

Correction Factor (260 nm)	0.911
Correction Factor (280 nm)	0.777
Extinction coefficient (cm ^-1 M ^-1)	21000
Excitation (nm)	298
Emission (nm)	617

Product Family

Name	Excitation (nm)	Emission (nm)	Extinction coefficient (cm ^-1 M ^-1)	Correction Factor (260 nm)	Correction Factor (280 nm)
trFluor™ Tb maleimide	333	544	-	0.942	0.797
trFluor™ Eu DBCO europium complex	298	617	21000	0.911	0.777

Images

Figure 1. Fluorescent dye maleimides are the most popular tool for conjugating dyes to a peptide, protein, antibody, thiol-modified oligonucleotide or nucleic acid through their SH group. Maleimides react readily with the thiol group of proteins, thiol-modified oligonucleotides, and other thiol-containing molecules under neutral conditions. The resulting dye conjugates are quite stable.

Citations

View all 1 citations: Citation Explorer

Biologischer Lichtsammler (LHCII) für Halbleiternanokristalle (Quantum Dots)
Authors: Werwie, Mara
Journal: (2013)

References

View all 61 references: Citation Explorer

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Journal: Assay Drug Dev Technol. (2012)

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A homogeneous single-label time-resolved fluorescence cAMP assay
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Journal: J Biomol Screen (2011): 356

Time-resolved fluorescence resonance energy transfer (TR-FRET) to analyze the disruption of EGFR/HER2 dimers: a new method to evaluate the efficiency of targeted therapy using monoclonal antibodies
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Homogeneous time-resolved fluorescence-based assay to screen for ligands targeting the growth hormone secretagogue receptor type 1a
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A time-resolved fluorescence-resonance energy transfer assay for identifying inhibitors of hepatitis C virus core dimerization
Authors: Kota S, Scampavia L, Spicer T, Beeler AB, Takahashi V, Snyder JK, Porco JA, Hodder P, Strosberg AD.
Journal: Assay Drug Dev Technol (2010): 96

Time-resolved FRET fluorescence spectroscopy of visible fluorescent protein pairs
Authors: Visser AJ, Laptenok SP, Visser NV, van Hoek A, Birch DJ, Brochon JC, Borst JW.
Journal: Eur Biophys J (2010): 241

Steady-state and time-resolved fluorescence quenching with transition metal ions as short-distance probes for protein conformation
Authors: Posokhov YO, Kyrychenko A, Ladokhin AS.
Journal: Anal Biochem (2010): 284

Ligand regulation of the quaternary organization of cell surface M3 muscarinic acetylcholine receptors analyzed by fluorescence resonance energy transfer (FRET) imaging and homogeneous time-resolved FRET
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Journal: J Biol Chem (2010): 23318