Fmoc-NMe-PEG4-acid

Fmoc-NMe-PEG4-acid is a PEG linker containing an Fmoc-protected amine and a terminal carboxylic acid. The hydrophilic PEG spacer increases the water solubility of a compound in aqueous media. The Fmoc group can be deprotected under basic condition to obtain the free amine which can be used for further conjugations. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond.