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AAT Bioquest

mFluor™ Violet 450 maleimide

AAT Bioquest\'s mFluor™ dyes are developed for multicolor flow cytometry-focused applications. These dyes have large Stokes Shifts, and can be well excited by the laser lines of flow cytometers (e.g., 405 nm, 488 nm and 633 nm). mFluor™ Violet 450 dyes have fluorescence excitation and emission maxima of ~405 nm and ~450 nm respectively. These spectral characteristics make them an excellent replacement for Pacific Blue™ labeling dye. mFluor™ Violet 450 maleimide is stable and shows good reactivity and selectivity with thiol group. mFluor™ Violet 450 maleimide provides a convenient tool to label monoclonal, polyclonal antibodies or other proteins (>10 kDa) for flow cytometric applications with the violet laser excitation.

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

mFluor™ Violet 450 maleimide stock solution (Solution B)

Add anhydrous DMSO into the vial of mFluor™ Violet 450 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.

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 mFluor™ Violet 450 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.

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of mFluor™ Violet 450 maleimide to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM150.46 µL752.298 µL1.505 mL7.523 mL15.046 mL
5 mM30.092 µL150.46 µL300.919 µL1.505 mL3.009 mL
10 mM15.046 µL75.23 µL150.46 µL752.298 µL1.505 mL

Molarity calculator

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

Mass (Calculate)Molecular weightVolume (Calculate)Concentration (Calculate)Moles
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Spectrum

Product family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
mFluor™ Violet 450 SE4064453500010.8110.3380.078
mFluor™ Violet 450-dUTP *1 mM in TE Buffer (pH 7.5)*4064453500010.8110.3380.078
mFluor™ Violet 530 maleimide505525200001---
mFluor™ Violet 610 maleimide5946129000010.310.5320.66
mFluor™ Violet 500 maleimide4105012500010.8110.7690.365

Citations

View all 3 citations: Citation Explorer
Deep Sequencing Analysis of the Eha-Regulated Transcriptome of Edwardsiella tarda Following Acidification
Authors: Gao, D and Liu, N and Li, Y and Zhang, Y and Liu, G and others, undefined
Journal: Metabolomics (Los Angel) (2017): 2153--0769
Suramin inhibits cullin-RING E3 ubiquitin ligases
Authors: Wu, Kenneth and Chong, Robert A and Yu, Qing and Bai, Jin and Spratt, Donald E and Ching, Kevin and Lee, Chan and Miao, Haibin and Tappin, Inger and Hurwitz, Jerard and others, undefined
Journal: Proceedings of the National Academy of Sciences (2016): E2011--E2018
Glycosaminoglycan mimicry by COAM reduces melanoma growth through chemokine induction and function
Authors: Piccard, Helene and Berghmans, Nele and Korpos, Eva and Dillen, Chris and Aelst, Ilse Van and Li, S and ra , undefined and Martens, Erik and Liekens, S and ra , undefined and Noppen, Sam and Damme, Jo Van and others, undefined
Journal: International Journal of Cancer (2012): E425--E436

References

View all 39 references: Citation Explorer
Development of new hCaM-Alexa Fluor(R) biosensors for a wide range of ligands
Authors: Velazquez-Lopez, I.; Leon-Cruz, E.; Pardo, J. P.; Sosa-Peinado, A.; Gonzalez-Andrade, M.
Journal: Anal Biochem (2017): 13-22
Synthetic Protocol for AFCS: A Biologically Active Fluorescent Castasterone Analog Conjugated to an Alexa Fluor 647 Dye
Authors: Winne, J. M.; Irani, N. G.; Van den Begin, J.; Madder, A.
Journal: Methods Mol Biol (2017): 21-Sep
Alteration of AMPA Receptor-Mediated Synaptic Transmission by Alexa Fluor 488 and 594 in Cerebellar Stellate Cells
Authors: Maroteaux, M.; Liu, S. J.
Journal: eNeuro (2016)
Alexa fluor-labeled fluorescent cellulose nanocrystals for bioimaging solid cellulose in spatially structured microenvironments
Authors: Grate, J. W.; Mo, K. F.; Shin, Y.; Vasdekis, A.; Warner, M. G.; Kelly, R. T.; Orr, G.; Hu, D.; Dehoff, K. J.; Brockman, F. J.; Wilkins, M. J.
Journal: Bioconjug Chem (2015): 593-601
In vivo visualization of GL261-luc2 mouse glioma cells by use of Alexa Fluor-labeled TRP-2 antibodies
Authors: Fenton, K. E.; Martirosyan, N. L.; Abdelwahab, M. G.; Coons, S. W.; Preul, M. C.; Scheck, A. C.
Journal: Neurosurg Focus (2014): E12
Page updated on December 6, 2024

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Physical properties

Molecular weight

664.63

Solvent

DMSO

Spectral properties

Absorbance (nm)

406

Correction Factor (260 nm)

0.338

Correction Factor (280 nm)

0.078

Extinction coefficient (cm -1 M -1)

350001

Excitation (nm)

406

Emission (nm)

445

Quantum yield

0.811

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
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.
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.
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.