We have found THPTA to be a highly efficient ligand for click chemistry with working ranges from 10nmol up to 1000nmol, in partially organic and completely aqueous reactions. Labeling is complete in as little as 15 minutes at room temperature. The ligand CuSO4 complex exhibits no loss of activity when frozen for at least a month.
TBTA overs most of the practical applications for Click Chemistry except for a completely aqueous conjugation reaction. The benefits of a completely aqueous reaction include the biological labeling of live cells or the labeling of proteins without the concern of denaturing secondary structures. The water-soluble tris(3-hydroxypropyltriazolylmethyl)amine (THPTA) click ligand further simplifies Click Chemistry by allowing the entire reaction to be run in water, affording biological compatibility for Click reactions. The THPTA ligand binds Cu(I), blocking the bioavailability of Cu(I) and ameliorating the potential toxic effects while maintaining the catalytic effectiveness in click conjugations. The THPTA ligand was effectively used to label live cells with high efficiency while maintaining cell viability.4
4. V. Hong, N.F. Steinmetz, M. Manchester, and M.G. Finn, Bioconjugate Chemistry, 2010, 21, 1912-1916.