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mFluor™ Red 780 Maleimide

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. mFluor Red 780 maleimide readily reacts 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. mFluor Red 780 maleimide readily reacts with the thiol group of proteins, thiol-modified oligonucleotides, and other thiol-containing molecules under neutral conditions. The resulting dye conjugates are quite stable.
Ordering information
Price ()
Catalog Number1192
Unit Size
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Additional ordering information
Telephone1-408-733-1055
Fax1-408-733-1304
Emailsales@aatbio.com
InternationalSee distributors
ShippingStandard overnight for United States, inquire for international
Physical properties
Molecular weight1168.28
SolventDMSO
Spectral properties
Absorbance (nm)630
Correction Factor (260 nm)0.101
Correction Factor (280 nm)0.116
Extinction coefficient (cm -1 M -1)900001
Excitation (nm)629
Emission (nm)767
Storage, safety and handling
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22
StorageFreeze (< -15 °C); Minimize light exposure
UNSPSC12171501

OverviewpdfSDSpdfProtocol


Molecular weight
1168.28
Absorbance (nm)
630
Correction Factor (260 nm)
0.101
Correction Factor (280 nm)
0.116
Extinction coefficient (cm -1 M -1)
900001
Excitation (nm)
629
Emission (nm)
767
mFluor™ Red 780 dyes are an excellent alternative to APC-Alexa Fluor® 750 tandems since they have the spectral properties equivalent to those of APC-Alexa Fluor® 750 conjugates. mFluor™ Red 780 dyes are water-soluble, and the protein conjugates prepared with mFluor™ Red 780 dyes are well excited at 633 nm or 647 nm to give red fluorescence (compatible with Cy7® filter). mFluor™ Red 780 dyes and conjugates are excellent red laser reagents for flow cytometry research. Compared to APC-Alexa Fluor® 750 tandems, mFluor™ Red 780 dyes are much more photostable, making them readily available for fluorescence imaging applications while it is very difficult to use the APC-Alexa Fluor® 750 conjugates for fluorescence imaging applications due to the rapid photobleaching of APC-Alexa Fluor® 750 tandems. mFluor™ Red 780 maleimide is stable and highly reacts with thiol-containing biomolecules such as reduced antibodies.

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. mFluor™ Red 780 maleimide stock solution (Solution B)
Add anhydrous DMSO into the vial of mFluor™ Red 780 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 mFluor™ Red 780 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™ Red 780 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 mM85.596 µL427.98 µL855.959 µL4.28 mL8.56 mL
5 mM17.119 µL85.596 µL171.192 µL855.959 µL1.712 mL
10 mM8.56 µL42.798 µL85.596 µL427.98 µL855.959 µL

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


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spectrum

Spectral properties

Absorbance (nm)630
Correction Factor (260 nm)0.101
Correction Factor (280 nm)0.116
Extinction coefficient (cm -1 M -1)900001
Excitation (nm)629
Emission (nm)767

Product family


NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Correction Factor (260 nm)Correction Factor (280 nm)
mFluor™ Red 780 SE6297679000010.1010.116

References


View all 30 references: Citation Explorer
Creation of a Nanobody-Based Fluorescent Immunosensor Mini Q-body for Rapid Signal-On Detection of Small Hapten Methotrexate.
Authors: Inoue, Akihito and Ohmuro-Matsuyama, Yuki and Kitaguchi, Tetsuya and Ueda, Hiroshi
Journal: ACS sensors (2020)
Synthesis of Quenchbodies for One-Pot Detection of Stimulant Drug Methamphetamine.
Authors: Jeong, Hee-Jin and Dong, Jinhua and Yeom, Chang-Hun and Ueda, Hiroshi
Journal: Methods and protocols (2020)
Site-Specific Fluorescent Labeling of Antibodies and Diabodies Using SpyTag/SpyCatcher System for In Vivo Optical Imaging.
Authors: Alam, Md Kausar and El-Sayed, Ayman and Barreto, Kris and Bernhard, Wendy and Fonge, Humphrey and Geyer, C Ronald
Journal: Molecular imaging and biology (2019): 54-66
Minimizing the Influence of Fluorescent Tags on IgG Partition in PEG-Salt Aqueous Two-Phase Systems for Rapid Screening Applications.
Authors: São Pedro, Mariana N and Azevedo, Ana M and Aires-Barros, Maria R and Soares, Ruben R G
Journal: Biotechnology journal (2019): e1800640
Optimizing leading edge F-actin labeling using multiple actin probes, fixation methods and imaging modalities.
Authors: DesMarais, Vera and Eddy, Robert J and Sharma, Ved P and Stone, Orrin and Condeelis, John S
Journal: BioTechniques (2019): 113-119
Covalent Modification of Biomolecules through Maleimide-Based Labeling Strategies.
Authors: Renault, Kévin and Fredy, Jean Wilfried and Renard, Pierre-Yves and Sabot, Cyrille
Journal: Bioconjugate chemistry (2018): 2497-2513
Antibody Binding at the Liposome-Water Interface: A FRET Investigation toward a Liposome-Based Assay.
Authors: Hoang, Hoa T and Mertens, Monique and Wessig, Pablo and Sellrie, Frank and Schenk, Jörg A and Kumke, Michael U
Journal: ACS omega (2018): 18109-18116
Site-Specifically Labeled Immunoconjugates for Molecular Imaging--Part 1: Cysteine Residues and Glycans.
Authors: Adumeau, Pierre and Sharma, Sai Kiran and Brent, Colleen and Zeglis, Brian M
Journal: Molecular imaging and biology (2016): 1-17
Nanobodies: site-specific labeling for super-resolution imaging, rapid epitope-mapping and native protein complex isolation.
Authors: Pleiner, Tino and Bates, Mark and Trakhanov, Sergei and Lee, Chung-Tien and Schliep, Jan Erik and Chug, Hema and Böhning, Marc and Stark, Holger and Urlaub, Henning and Görlich, Dirk
Journal: eLife (2015): e11349
Evaluation of chemical fluorescent dyes as a protein conjugation partner for live cell imaging.
Authors: Hayashi-Takanaka, Yoko and Stasevich, Timothy J and Kurumizaka, Hitoshi and Nozaki, Naohito and Kimura, Hiroshi
Journal: PloS one (2014): e106271