AAT Bioquest

FastClick™ XFD405 Alkyne

The reaction (Green Bar) of FastClick Cy5 Alkyne with coumarin azide occurs under extremely mild conditions (e.g., [Azide] = 0.02 mM, [Alkyne] = 0.02 mM, [CuSO4] = 0.02 mM, [Sodium Ascorbate] = 5 mM, in 100 mM HEPES) under which the common Cy5 alkyne does not effectively react with the coumarin azide substrate.
The reaction (Green Bar) of FastClick Cy5 Alkyne with coumarin azide occurs under extremely mild conditions (e.g., [Azide] = 0.02 mM, [Alkyne] = 0.02 mM, [CuSO4] = 0.02 mM, [Sodium Ascorbate] = 5 mM, in 100 mM HEPES) under which the common Cy5 alkyne does not effectively react with the coumarin azide substrate.
The reaction (Green Bar) of FastClick Cy5 Alkyne with coumarin azide occurs under extremely mild conditions (e.g., [Azide] = 0.02 mM, [Alkyne] = 0.02 mM, [CuSO4] = 0.02 mM, [Sodium Ascorbate] = 5 mM, in 100 mM HEPES) under which the common Cy5 alkyne does not effectively react with the coumarin azide substrate.
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Physical properties
Molecular weight940.07
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
Alternative formats
FastClick™ XFD405 Azide


See also: Click Chemistry
Molecular weight
FastClick™ XFD405 Alkyne contains both the CAG moiety of FastClick (for assisting click efficiency) and Alexa Fluor® 405 fluorophore (as the fluorescence tag) for developing Alexa Fluor® 405-based fluorescent probes. FastClick™ XFD405 Alkyne readily reacts with azido-modified biomolecules. Alexa Fluor® 405 is a commonly used blue fluorophore for labeling proteins, nucleic acids, or other biomolecules. It has moderate photostability and excitation that matches the 405 nm laser line. Its conjugates are used for imaging and flow cytometry applications. It has an excitation wavelength of 405 nm and an emission wavelength of 421 nm. It is water soluble pyrene derivative that has pH-insensitive fluorescence from pH 4 to pH 10. Alexa Fluor® is a trademark of ThermoFisher Scientific. FastClick™ reagents have been developed by the scientists of AAT Bioquest for enhancing the yield and reaction speed of copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. They contain a copper-chelating ligand that significantly stabilizes the Cu(I) oxidation state and thus accelerates the click reaction. They do not require the use of an external copper-chelator (such as the common THPTA or BTTAA). The high concentration of copper chelators is known to have a detrimental effect on DNA/RNA, thus causing biocompatibility issues. The introduction of a copper-chelating moiety at the reporter molecule allows for a dramatic raise of the effective Cu(I) concentration at the reaction site and thus accelerates the reaction. Under extremely mild conditions the FastClick™ azides and alkynes react much faster in high yield compared to the corresponding conventional CuAAC reactions. Click chemistry was developed by K. Barry Sharpless as a robust and specific method of ligating two molecules together. Two important characteristics make click chemistry attractive for assembling biomolecules. First, click reactions are bio-orthogonal, thus the click chemistry-functionalized biomolecules would not react with the natural biomolecules that lack a clickable functional group. Second, the reactions proceed with ease under mild conditions, such as at room temperature and in aqueous media.


Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of FastClick™ XFD405 Alkyne 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 mM106.375 µL531.875 µL1.064 mL5.319 mL10.638 mL
5 mM21.275 µL106.375 µL212.75 µL1.064 mL2.128 mL
10 mM10.638 µL53.188 µL106.375 µL531.875 µL1.064 mL

Molarity calculator

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

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

Product Family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
FastClick™ Cy3 Alkyne55556915000010.1510.070.073
FastClick™ Cy5 Alkyne65167025000010.271, 0.420.020.03
FastClick™ Cy7 Alkyne7567792500000.30.050.036
FastClick™ XFD350 Alkyne34344119000-0.250.19
FastClick™ XFD488 Alkyne499520710000.9210.300.11
FastClick™ XFD555 Alkyne5535681500000.110.080.08
FastClick™ XFD647 Alkyne6506712390000.3310.000.03
FastClick™ XFD750 Alkyne7527762400000.1210.000.04



View all 37 references: Citation Explorer
Click-Functionalization of Silanized Carbon Nanotubes: From Inorganic Heterostructures to Biosensing Nanohybrids.
Authors: Manoharan, Gririraj and Bösel, Petra and Thien, Jannis and Holtmannspötter, Michael and Meingast, Laura and Schmidt, Mercedes and Eickmeier, Henning and Haase, Markus and Maultzsch, Janina and Steinhart, Martin and Wollschläger, Joachim and Palma, Matteo and Meyer, Carola
Journal: Molecules (Basel, Switzerland) (2023)
Diyne inactivators and activity-based fluorescent labeling of phenol hydroxylase in Pseudomonas sp. CF600.
Authors: Oyarzun Mejia, Alejandra P and Hyman, Michael R
Journal: FEMS microbiology letters (2023)
Monitoring the Sialome on Human Immune Cells.
Authors: O'Farrell, Laura K and Fraser, Alexander D and Davey, Gavin P
Journal: Methods in molecular biology (Clifton, N.J.) (2022): 323-329
Bivalent EGFR-Targeting DARPin-MMAE Conjugates.
Authors: Karsten, Lennard and Janson, Nils and Le Joncour, Vadim and Alam, Sarfaraz and Müller, Benjamin and Tanjore Ramanathan, Jayendrakishore and Laakkonen, Pirjo and Sewald, Norbert and Müller, Kristian M
Journal: International journal of molecular sciences (2022)
Differential Labeling of Chemically Modified Peptides and Lipids among Cyanobacteria Planktothrix and Microcystis.
Authors: Morón-Asensio, Rubén and Schuler, David and Wiedlroither, Anneliese and Offterdinger, Martin and Kurmayer, Rainer
Journal: Microorganisms (2021)
Controlled Monofunctionalization of Molecular Spherical Nucleic Acids on a Buckminster Fullerene Core.
Authors: Gulumkar, Vijay and Äärelä, Antti and Moisio, Olli and Rahkila, Jani and Tähtinen, Ville and Leimu, Laura and Korsoff, Niko and Korhonen, Heidi and Poijärvi-Virta, Päivi and Mikkola, Satu and Nesati, Victor and Vuorimaa-Laukkanen, Elina and Viitala, Tapani and Yliperttula, Marjo and Roivainen, Anne and Virta, Pasi
Journal: Bioconjugate chemistry (2021): 1130-1138
Protocol for visualizing newly synthesized proteins in primary mouse hepatocytes.
Authors: Shen, Yuqian and Liu, Wenhua and Zuo, Jian and Han, Junhai and Zhang, Zi Chao
Journal: STAR protocols (2021): 100616
Authors: Koch, Peter D and Quintana, Jeremy and Ahmed, Maaz and Kohler, Rainer H and Weissleder, Ralph
Journal: Advanced therapeutics (2021)
A novel tracer for in vivo optical imaging of fatty acid metabolism in the heart and brown adipose tissue.
Authors: Panagia, Marcello and Yang, Jing and Gale, Eric and Wang, Huan and Luptak, Ivan and Chen, Howard H and Patel, Dakshesh and Croteau, Dominique and Pimentel, David Richard and Bachschmid, Markus Michael and Colucci, Wilson S and Ran, Chongzhao and Sosnovik, David E
Journal: Scientific reports (2020): 11209
Nanobody click chemistry for convenient site-specific fluorescent labelling, single step immunocytochemistry and delivery into living cells by photoporation and live cell imaging.
Authors: Hebbrecht, Tim and Liu, Jing and Zwaenepoel, Olivier and Boddin, Gaëlle and Van Leene, Chloé and Decoene, Klaas and Madder, Annemieke and Braeckmans, Kevin and Gettemans, Jan
Journal: New biotechnology (2020): 33-43