APN-C3-PEG5-acid

APN-C3-PEG5-acid is a thiol-specific conjugation linker. It contains a thiol-reactive 3-arylpropiolonitrile (APN) group and an azide group. The aqueous stable APN group couples specifically with cysteine thiol of biomolecules to form a stable thioether linkage without the risk of subsequent side reactions that can occur with maleimides. The azide group can react with alkyne, BCN, DBCO via Click Chemistry to afford a stable triazole linkage. The PEG spacer increases the aqueous solubility of the resulting compound.