Biotin-label azide-tagged molecules for specific detection or purification.

Thermo Scientific Biotin-PEG3-Phosphine is a versatile biotinylation reagent for labeling azide-containing molecules. The phosphine group reacts with an azide to produce an aza-ylide intermediate that is trapped to form a stable, covalent amide bond, which is also referred to as the Staudinger reaction.

The azide group, which is the reactive target of phosphine-activated biotin, can be introduced into proteins or other cellular targets via azide reagents or through in vivo labeling with azide-derivatives of naturally occurring metabolic building blocks. Because neither phosphines nor azides are present in biological systems, they comprise chemoselective (mutually specific) ligation pairs for labeling and conjugation.

Thus, when used in combination with azide labeling strategies, Biotin-PEG3-Phosphine enables directed biotin labeling to facilitate detection or affinity purification of protein interactions and post-translational modifications using streptavidin probes or streptavidin agarose resins.

Highlights:

• Soluble – easily dissolves in water-miscible solvents (e.g., DMSO) for subsequent dilution in aqueous reaction mixtures with cell lysates and other biological samples
• Compatible – reaction chemistry occurs effectively in simple buffer conditions; requires no accessory reagents such as copper or reducing agents
• Chemoselective – the phosphine reactive group is specific in biological samples for azide-tagged molecules, ensuring that biotinylation is specific
• PEG spacer – polyethylene glycol spacer arm helps maintain solubility of labeled molecules and decreases steric hindrance for affinity-binding to avidin, streptavidin or NeutrAvidin Protein

Chemical structure of Biotin-PEG3-Phosphine, a Staudinger ligation reagent.

 

Example strategy for in vivo metabolic labeling with biotin using Biotin-PEG3-Phosphine. When bioorthogonal azido-sugar derivatives are supplied to living cells, they become incorporated into glycoprotein structures by endogenous post-translational modification mechanisms. The azide-tagged molecules can then be selectively labeled or conjugated to phosphine-activated molecules, in this case, a derivative of biotin. If the azido sugars were supplied to cells being studied for response to a particular treatment, the biotin affinity-tag could be used to purify and analyze differences in glycosylation resulting from the treatment regime.

 

Related Products and Resources:

• Azide-Phosphine Reagent Guide – complete product list of available reagents
• Metabolic Labeling for Chemoselective Ligation – description and examples of chemoselective ligation and bioorthogonal in vivo labeling strategies
• Staudinger Ligation Reaction Chemistry – diagram and more detailed description of the azide-phosphine reaction chemistry
• Superiority of Azide-Phosphine Chemistry – experimental data comparing Staudinger ligation to azide-alkyne "click" chemistry
• Protein Methods Library – links to articles about other crosslinking and labeling techniques

  Product #	Description	Pkg. Size
  88901	Biotin-PEG3-Phosphine	10mg