Boc-NH-PEG(3)-COOH

t-Boc-N-amido-PEG4-CH2CO2H is a PEG linker containing a terminal carboxylic acid and Boc-protected amino group. The hydrophilic PEG spacer increases solubility in aqueous media. 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. The Boc group can be deprotected under mild acidic conditions to form the free amine.

This heterobifunctional, PEGylated crosslinker features a carboxylic acid at one end and Boc-protected amino group at the other, which can be deprotected with mildly acidic conditions. The hydrophillic PEG linker facilitates solubility in biological applications. BocNH-PEG4-acid can be used for bioconjugation or as a building block for synthesis of small molecules, conjugates of small molecules and/or biomolecules, or other tool compounds for chemical biology and medicinal chemistry that require ligation. Examples of applications include its synthetic incorporation into antibody-drug conjugates or proteolysis-targeting chimeras (PROTAC^? molecules) for targeted protein degradation