iFluor® 560 succinimidyl ester
Product key features
- Superior Solubility: Enhanced aqueous solubility for efficient biomolecule conjugation.
- High Photostability: High quantum yield and stability facilitate the detection of low-abundance targets with greater sensitivity
- Versatile Conjugation: Succinimidyl ester chemistry enables efficient and stable labeling of proteins, antibodies, and other amine-containing molecules.
- Ex/Em of the conjugate: 560/571 nm
- Extinction coefficient: 120,000 cm-1M-1
- Spectrally similar dyes: Cy3, Cy3B
- Molecular weight: 1257.45
Product description
Cy3 is recognized as the dimmest fluorophore in the Cy dye family. To overcome this limitation, Cy3B was developed as an enhanced derivative, exhibiting a substantial increase in fluorescence quantum yield and photostability. Despite these improvements, Cy3B's limited aqueous solubility presents significant challenges for its efficient conjugation to biomolecules. In response, iFluor® 560 has been introduced, offering enhanced water solubility while retaining spectral properties closely aligned with both Cy3B and Cy3, positioning it as a robust alternative for the development of bioconjugates with bright orange fluorescence. It is optimally excited by 532 nm and 561 nm laser lines and is fully compatible with TRITC filter sets, facilitating its integration into existing experimental workflows. iFluor® 560 is suitable for labeling a wide range of antigens, including cell surface, intracellular, and intranuclear targets. It performs exceptionally well in complex multicolor panels, bridging the gap between fluorophores like FITC and PE. In simpler panels, iFluor® 560 can effectively replace PE to minimize emission spreading into PE tandem dyes. This dye allows for high molar ratio conjugation to proteins with minimal self-quenching, resulting in brighter conjugates. Its robust fluorescence quantum yield and photostability make iFluor® 560 ideal for detecting low-abundance biological targets, delivering greater precision and sensitivity in quantitative fluorescence assays.
The succinimidyl ester of iFluor® 560 is a widely used reagent for the conjugation of this dye to proteins or antibodies. Succinimidyl esters react selectively and efficiently with primary amines (such as the side chains of lysine residues or aminosilane-coated surfaces) at pH 7-9, forming stable covalent amide bonds. This property makes iFluor® 560 succinimidyl ester an excellent choice for labeling proteins, amine-modified oligonucleotides, and other amine-containing molecules.
Example protocol
PREPARATION OF STOCK SOLUTIONS
Note The pH of the protein solution (Solution A) should be 8.5 ± 0.5. If the pH of the protein solution is lower than 8.0, adjust the pH to the range of 8.0-9.0 using 1 M sodium bicarbonate solution or 1 M pH 9.0 phosphate buffer.
Note The protein should be dissolved in 1X phosphate buffered saline (PBS), pH 7.2-7.4. If the protein is dissolved in Tris or glycine buffer, it must be dialyzed against 1X PBS, pH 7.2-7.4, to remove free amines or ammonium salts (such as ammonium sulfate and ammonium acetate) that are widely used for protein precipitation.
Note Impure antibodies or antibodies stabilized with bovine serum albumin (BSA) or gelatin will not be labeled well. The presence of sodium azide or thimerosal might also interfere with the conjugation reaction. Sodium azide or thimerosal can be removed by dialysis or spin column for optimal labeling results.
Note The conjugation efficiency is significantly reduced if the protein concentration is less than 2 mg/mL. For optimal labeling efficiency the final protein concentration range of 2-10 mg/mL is recommended.
Note Prepare the dye stock solution (Solution B) before starting the conjugation. Use promptly. Extended storage of the dye stock solution may reduce the dye activity. Solution B can be stored in freezer for two weeks when kept from light and moisture. Avoid freeze-thaw cycles.
SAMPLE EXPERIMENTAL PROTOCOL
Note Each protein requires distinct dye/protein ratio, which also depends on the properties of dyes. Over labeling of a protein could detrimentally affects its binding affinity while the protein conjugates of low dye/protein ratio gives reduced sensitivity.
- Use 10:1 molar ratio of Solution B (dye)/Solution A (protein) as the starting point: Add 5 µL of the dye stock solution (Solution B, assuming the dye stock solution is 10 mM) into the vial of the protein solution (95 µL of Solution A) with effective shaking. The concentration of the protein is ~0.05 mM assuming the protein concentration is 10 mg/mL and the molecular weight of the protein is ~200KD.
Note We recommend to use 10:1 molar ratio of Solution B (dye)/Solution A (protein). If it is too less or too high, determine the optimal dye/protein ratio at 5:1, 15:1 and 20:1 respectively. - Continue to rotate or shake the reaction mixture at room temperature for 30-60 minutes.
- Prepare Sephadex G-25 column according to the manufacture instruction.
- Load the reaction mixture (From "Run conjugation reaction") to the top of the Sephadex G-25 column.
- Add PBS (pH 7.2-7.4) as soon as the sample runs just below the top resin surface.
- Add more PBS (pH 7.2-7.4) to the desired sample to complete the column purification. Combine the fractions that contain the desired dye-protein conjugate.
Note For immediate use, the dye-protein conjugate need be diluted with staining buffer, and aliquoted for multiple uses.
Note For longer term storage, dye-protein conjugate solution need be concentrated or freeze dried.
Calculators
Common stock solution preparation
0.1 mg | 0.5 mg | 1 mg | 5 mg | 10 mg | |
1 mM | 79.526 µL | 397.63 µL | 795.26 µL | 3.976 mL | 7.953 mL |
5 mM | 15.905 µL | 79.526 µL | 159.052 µL | 795.26 µL | 1.591 mL |
10 mM | 7.953 µL | 39.763 µL | 79.526 µL | 397.63 µL | 795.26 µL |
Molarity calculator
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Spectrum
Product family
Name | Excitation (nm) | Emission (nm) | Extinction coefficient (cm -1 M -1) | Quantum yield | Correction Factor (260 nm) | Correction Factor (280 nm) |
iFluor® 350 succinimidyl ester | 345 | 450 | 200001 | 0.951 | 0.83 | 0.23 |
iFluor® 405 succinimidyl ester | 403 | 427 | 370001 | 0.911 | 0.48 | 0.77 |
iFluor® 488 succinimidyl ester | 491 | 516 | 750001 | 0.91 | 0.21 | 0.11 |
iFluor® 514 succinimidyl ester | 511 | 527 | 750001 | 0.831 | 0.265 | 0.116 |
iFluor® 532 succinimidyl ester | 537 | 560 | 900001 | 0.681 | 0.26 | 0.16 |
iFluor® 555 succinimidyl ester | 557 | 570 | 1000001 | 0.641 | 0.23 | 0.14 |
iFluor® 594 succinimidyl ester | 587 | 603 | 2000001 | 0.531 | 0.05 | 0.04 |
iFluor® 633 succinimidyl ester | 640 | 654 | 2500001 | 0.291 | 0.062 | 0.044 |
iFluor® 647 succinimidyl ester | 656 | 670 | 2500001 | 0.251 | 0.03 | 0.03 |
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