Alkyne groups preferentially label molecules containing azide groups (-N3). Copper-catalyzed Click Chemistry is used for initiating reactions between alkynes and azides.
Within physiological temperature and pH ranges, the alkyne group does not react with amines or hydroxyls, which are naturally present in many biomolecules. However, at higher pH or upon exposure to short-wave ultraviolet (UV) light, the alkyne group may become unstable towards sulfhydryls (-SH, thiols), organophosphines such as tris(2-carboxylethyl)phosphine (TCEP), and dihalogens such as iodine (I2).
