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AAT Bioquest

iFluor® 460 maleimide

AAT Bioquest's iFluor® dyes are optimized for labeling proteins, particularly antibodies. These dyes are bright, photostable, and have minimal quenching on proteins. Although the 460 nm blue diode laser is being installed in numerous new fluorescence instruments, few dyes can be well excited at 460 nm. iFluor® 460 is optimized to be well excited by the blue diode laser at 460 nm, enabling new biological applications for the new fluorescence instruments equipped with the 460 nm blue diode laser. iFluor® 460 maleimide is stable and shows good reactivity and selectivity with the thiol group.

Example protocol

PREPARATION OF STOCK SOLUTIONS

Unless otherwise noted, all unused stock solutions should be divided into single-use aliquots and stored at -20 °C after preparation. Avoid repeated freeze-thaw cycles.

1. iFluor™ 460 maleimide stock solution (Solution B)
Add anhydrous DMSO into the vial of iFluor™ 460 maleimide to make a 10 mM stock solution. Mix well by pipetting or vortex.
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 upto 4 weeks when kept from light and moisture. Avoid freeze-thaw cycles.


2. Protein stock solution (Solution A)
Mix 100 µL of a reaction buffer (e.g., 100 mM MES buffer with pH ~6.0) with 900 µL of the target protein solution (e.g. antibody, protein concentration >2 mg/mL if possible) to give 1 mL protein labeling stock solution.
Note     The pH of the protein solution (Solution A) should be 6.5 ± 0.5.
Note     Impure antibodies or antibodies stabilized with bovine serum albumin (BSA) or other proteins will not be labeled well.
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.

Optional: if your protein does not contain a free cysteine, you must treat your protein with DTT or TCEP to generate a thiol group. DTT or TCEP are used for converting a disulfide bond to two free thiol groups. If DTT is used you must remove free DTT by dialysis or gel filtration before conjugating a dye maleimide to your protein. Following is a sample protocol for generating a free thiol group:
  1. Prepare a fresh solution of 1 M DTT (15.4 mg/100 µL) in distilled water.
  2. Make IgG solution in 20 mM DTT: add 20 µL of DTT stock per ml of IgG solution while mixing. Let stand at room temp for 30 minutes without additional mixing (to minimize reoxidation of cysteines to cystines).
  3. Pass the reduced IgG over a filtration column pre-equilibrated with "Exchange Buffer". Collect 0.25 mL fractions off the column.
  4. Determine the protein concentrations and pool the fractions with the majority of the IgG. This can be done either spectrophotometrically or colorimetrically.
  5. Carry out the conjugation as soon as possible after this step (see Sample Experiment Protocol).
    Note     IgG solutions should be >4 mg/mL for the best results. The antibody should be concentrated if less than 2 mg/mL. Include an extra 10% for losses on the buffer exchange column.
    Note     The reduction can be carried out in almost any buffers from pH 7-7.5, e.g., MES, phosphate or TRIS buffers.
    Note     Steps 3 and 4 can be replaced by dialysis. 

SAMPLE EXPERIMENTAL PROTOCOL

This labeling protocol was developed for the conjugate of Goat anti-mouse IgG with iFluor™ 460 maleimide. You might need further optimization for your particular proteins.
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.


Run conjugation reaction
  1. 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.
  2. Continue to rotate or shake the reaction mixture at room temperature for 30-60 minutes. 

Purify the conjugation
The following protocol is an example of dye-protein conjugate purification by using a Sephadex G-25 column.
  1. Prepare Sephadex G-25 column according to the manufacture instruction.
  2. Load the reaction mixture (From "Run conjugation reaction") to the top of the Sephadex G-25 column.
  3. Add PBS (pH 7.2-7.4) as soon as the sample runs just below the top resin surface.
  4. 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. 

Spectrum

Product family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
iFluor® 350 maleimide3454502000010.9510.830.23
iFluor® 488 maleimide4915167500010.910.210.11
iFluor® 555 maleimide55757010000010.6410.230.14
iFluor® 647 maleimide65667025000010.2510.030.03
iFluor® 680 maleimide68470122000010.2310.0970.094
iFluor® 700 maleimide69071322000010.2310.090.04
iFluor® 750 maleimide75777927500010.1210.0440.039
iFluor® 790 maleimide78781225000010.1310.10.09
iFluor® 800 maleimide80182025000010.1110.030.08
iFluor® 810 maleimide81182225000010.0510.090.15
iFluor® 820 maleimide82285025000010.110.16
iFluor® 860 maleimide85387825000010.10.14
iFluor® 532 maleimide5375609000010.6810.260.16
iFluor® 594 maleimide58760320000010.5310.050.04
iFluor® 405 maleimide4034273700010.9110.480.77
iFluor® 430 maleimide4334984000010.7810.680.3
iFluor® 568 maleimide56858710000010.5710.340.15
iFluor® 633 maleimide64065425000010.2910.0620.044
iFluor® 450 maleimide4515024000010.8210.450.27
iFluor® 665 maleimide667692110,00010.2210.120.09
iFluor® 460 Styramide468493800001~0.810.980.46
iFluor® 546 maleimide54155710000010.6710.250.15
iFluor® 840 maleimide8368792000001-0.20.09
iFluor® 770 maleimide77779725000010.160.090.08
iFluor® 780 maleimide78480825000010.1610.130.12
iFluor® 830 maleimide830867----
iFluor® 514 maleimide5115277500010.8310.2650.116
iFluor® 660 maleimide66367825000010.2610.070.08
iFluor® 670 maleimide67168220000010.5510.030.033
iFluor® 720 maleimide71674024000010.1410.150.13
Show More (21)

References

View all 50 references: Citation Explorer
Toward the Clinical Development and Validation of a Thy1-Targeted Ultrasound Contrast Agent for the Early Detection of Pancreatic Ductal Adenocarcinoma.
Authors: Bam, Rakesh and Daryaei, Iman and Abou-Elkacem, Lotfi and Vilches-Moure, Jose G and Meuillet, Emmanuelle J and Lutz, Amelie and Marinelli, Edmund R and Unger, Evan C and Gambhir, Sanjiv S and Paulmurugan, Ramasamy
Journal: Investigative radiology (2020)
Tracking the physical stability of fluorescent-labeled mAbs under physiologic in vitro conditions in human serum and PBS.
Authors: Schuster, Joachim and Mahler, Hanns-Christian and Koulov, Atanas and Joerg, Susanne and Racher, Andy and Huwyler, Joerg and Detampel, Pascal and Mathaes, Roman
Journal: European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenst (2020): 193-201
Folding of single-stranded circular DNA into rigid rectangular DNA accelerates its cellular uptake.
Authors: Ohtsuki, Shozo and Shiba, Yukako and Maezawa, Tatsuoki and Hidaka, Kumi and Sugiyama, Hiroshi and Endo, Masayuki and Takahashi, Yuki and Takakura, Yoshinobu and Nishikawa, Makiya
Journal: Nanoscale (2019): 23416-23422
Combined effect of propranolol, vincristine and bevacizumab on HUVECs and BJ cells.
Authors: Bota, Mădălina and Fischer-Fodor, Eva and Bochiș, Ovidiu-Vasile and Cenariu, Mihai and Popa, Gheorghe and Blag, Cristina Lucia and Tătaru, Alexandru
Journal: Experimental and therapeutic medicine (2019): 307-315
Cell-type-specific quantification of protein synthesis in vivo.
Authors: Hidalgo San Jose, Lorena and Signer, Robert A J
Journal: Nature protocols (2019): 441-460
Page updated on October 8, 2024

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Physical properties

Molecular weight

831.88

Solvent

DMSO

Spectral properties

Correction Factor (260 nm)

0.98

Correction Factor (280 nm)

0.46

Extinction coefficient (cm -1 M -1)

800001

Excitation (nm)

468

Emission (nm)

493

Quantum yield

~0.81

Storage, safety and handling

H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22

Storage

Freeze (< -15 °C); Minimize light exposure
UNSPSC12171501