AAT Bioquest

FastClick™ XFD350 Azide

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The reaction (Green Bar) of FastClick Cy5 Azide with coumarin alkyne 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 azide does not effectively react with the coumarin alkyne substrate.
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Physical properties
Molecular weight525.54
Spectral properties
Correction Factor (260 nm)0.25
Correction Factor (280 nm)0.19
Extinction coefficient (cm -1 M -1)19000
Excitation (nm)343
Emission (nm)441
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™ XFD350 Alkyne


See also: Click Chemistry
Molecular weight
Correction Factor (260 nm)
Correction Factor (280 nm)
Extinction coefficient (cm -1 M -1)
Excitation (nm)
Emission (nm)
FastClick™ XFD350 Azide contains both the CAG moiety of FastClick (for assisting click efficiency) and Alexa Fluor® 350 fluorophore (as the fluorescence tag) for developing Alexa Fluor® 350-based fluorescent probes. Alexa Fluor® 350 is a commonly used blue fluorophore for labeling proteins, nucleic acids, or other biomolecules. It has moderate photostability and excitation that matches the 350 nm laser line. 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™ XFD350 Azide 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 mM190.28 µL951.402 µL1.903 mL9.514 mL19.028 mL
5 mM38.056 µL190.28 µL380.561 µL1.903 mL3.806 mL
10 mM19.028 µL95.14 µL190.28 µL951.402 µL1.903 mL

Molarity calculator

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Spectral properties

Correction Factor (260 nm)0.25
Correction Factor (280 nm)0.19
Extinction coefficient (cm -1 M -1)19000
Excitation (nm)343
Emission (nm)441

Product Family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
FastClick™ Cy3 Azide55556915000010.1510.070.073
FastClick™ Cy5 Azide65167025000010.271, 0.420.020.03
FastClick™ Cy7 Azide7567792500000.30.050.036
FastClick™ XFD488 Azide499520710000.9210.300.11
FastClick™ XFD555 Azide5535681500000.110.080.08
FastClick™ XFD647 Azide6506712390000.3310.000.03
FastClick™ XFD750 Azide7527762400000.1210.000.04



View all 46 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)
Click-iT ® Plus OPP Alexa Fluor ® Protein Synthesis Assay in Embryonic Cells.
Authors: Li, Yan and Ji, Xu and Chang, Lu and Tang, Jianan and Hua, Min-Min and Liu, Jing and O'Neill, Christopher and Huang, Xuefeng and Jin, Xingliang
Journal: Bio-protocol (2022): e4441
Recyclable cell-surface chemical tags for repetitive cancer targeting.
Authors: Bhatta, Rimsha and Han, Joonsu and Zhou, Jingyi and Li, Haoyu and Wang, Hua
Journal: Journal of controlled release : official journal of the Controlled Release Society (2022): 164-174
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
EdU Incorporation To Assess Cell Proliferation and Drug Susceptibility in Naegleria fowleri.
Authors: Troth, Emma V and Kyle, Dennis E
Journal: Antimicrobial agents and chemotherapy (2021): e0001721
Azide-Functionalized Naphthoxyloside as a Tool for Glycosaminoglycan Investigations.
Authors: Willén, Daniel and Mastio, Roberto and Söderlund, Zackarias and Manner, Sophie and Westergren-Thorsson, Gunilla and Tykesson, Emil and Ellervik, Ulf
Journal: Bioconjugate chemistry (2021): 2507-2515
Authors: Koch, Peter D and Quintana, Jeremy and Ahmed, Maaz and Kohler, Rainer H and Weissleder, Ralph
Journal: Advanced therapeutics (2021)
Clickable Galactose Analogues for Imaging Glycans in Developing Zebrafish.
Authors: Daughtry, Jessica L and Cao, Wendy and Ye, Johnny and Baskin, Jeremy M
Journal: ACS chemical biology (2020): 318-324
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
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