The NHS-Azide and NHS-Phosphine Reagents are amine-reactive compounds for derivatising primary amines of proteins or amine-coated polymer surfaces. Once a protein or surface is azide- or phosphine-labelled, the two components are mixed for effective and stable conjugation. Phosphine groups react with azides via a Staudinger reaction to produce an aza-ylide intermediate that is trapped to form a stable, covalent amide bond. Because phosphines and azides are absent from biological systems, there is minimal background labelling of macromolecules found in cells or lysates.

• Reagent Easily Dissolves in Water-Miscible Solvents 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
• NHS Esters are Specific for Covalent Attachment to Primary Amines (Side Chain of Lysine or N-terminus of Polypeptides)
• Chemoselective Azide and Phosphine Groups do not React or Interfere with Components of Biological Samples (Bioorthogonal) but Conjugate to One Another with High Efficiency

This NHS-ester compound reacts to form covalent bonds with primary amines (e.g., side chain of lysine residues or aminosilane-coated surfaces). The azide (N3) group reacts with phosphine-labeled molecules by a mechanism known as Staudinger chemistry, enabling efficient and specific conjugation of derivatized molecules in biological samples.