Dde TAMRA Biotin Azide is a trifunctional, cleavable probe that allows for efficient recovery of avidin-bound protein complexes in affinity-based assays. This reagent contains a fluorescent dye (TAMRA) and biotin moiety linked to azide group through a spacer arm containing a hydrazine-cleavable Dde moiety. Under mild conditions (2% aqueous hydrazine), the Dde liner is cleaved, releasing the biotin tag and any avidin conjugate bound to it.

Trifunctional Click Chemistry Probes that incorporate a ligation handle, a biotin and a fluorophore have become a popular tool for for tandem labeling of proteins and subsequent detection or enrichment. However, due to the strong interaction between biotin and streptavidin harsh conditions are necessary for the elution of enriched proteins. This usually leads to contamination of the sample with non-specifically bound proteins and endogenously biotinlytated proteins, which complicates target identification.

Cleavable Trifunctional Click Chemistry Probes overcome this major drawback of the streptavidin-biotin affinity purification. These probes contain a biotin moiety linked to a “clickable” group and fluorescent dye through a spacer arm containing a cleavable Dde linker. Dde moiety is stable to rigorous, denaturing wash conditions, acidic or basic conditions including generally applied buffer systems to which the biological sample may be exposed. At the same time Dde linker can be quantitatively cleaved under mild aqueous buffered conditions with 2% hydrazine.

Another very important advantage of dual label probes over regular biotin probes is built-in control. Each step of enrichment process can easily followed either by UV-Vis (550 nm) or by more sensitive fluorescence spectroscopy. After elution form streptavidin beads target proteins containing TAMRA label can be easily distinguished from non-specifically bound proteins and endogenously biotinlytated proteins.

This new dual label probe should be useful to expand the new applications of standard biotin–streptavidin technology.