AFDye™ 350 Picolyl Azide (Alexa Fluor® 350 Picolyl Azide equivalent) is an advanced fluorescent probe that incorporates a copper-chelating motif in order to raise the effective concentration of Cu(I) at the reaction site. The rate of the CuAAC reaction depends on the concentrations of all reagents, including copper, therefore raising the effective copper concentration at the reaction site dramatically increases the rate of the CuAAC reaction without needing to increase the concentration of azide reagent or copper.
In addition, the use of AFDye™ 350 Picolyl Azide instead of conventional azides allows for at least a tenfold reduction in the concentration of the copper catalyst without sacrificing the efficiency of labeling.
In summary, the introduction of a picolyl moiety into an azide probe leads to a substantial increase in the sensitivity of alkyne detection. This is of special value for the detection of low abundance targets or where significant increase in signal intensity is desired. AFDye™ 350 Picolyl Azide is a blue-fluorescent azide-activated probe that reacts with terminal alkynes via a copper-catalyzed click reaction (CuAAC). It also reacts with strained cyclooctyne via a copper-free click chemistry reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures.
AFDye™ 350 dye is structurally identical to Invitrogen’s Alexa Fluor® Dye 350.