Azide-containing FLAG tag reagents can be used for the introduction of a FLAG-tag to terminal Alkyne and strained Alkyne (e.g. DBCO)-labeled biomolecules via Cu(I)-catalyzed Alknye-Azide (CUAAC) or Cu(I)-free strain-promoted Alkyne-Azide Click Chemistry (SPAAC) reaction, respectively.
Molecule solubility and efficient FLAG-tag detection is ensured by the integrated PEG-linker.
 Hopp et al. (1988) A Short Polypeptide Marker Sequence Useful for Recombinant Protein Identification and Purification. Bio/Technology 6:1204.
 Einhauer et al. (2001) The FLAG peptide, a versatile fusion tag for the purification of recombinant proteins. J. Biochem. Biophys. Methods 49:455.
 Brizzard et al. (1997) Epitope tagging of recombinant proteins. Current Protocols in Neuroscience:5.8.1.