Methylamino-PEG4-acid

Methylamino-PEG4-acid is a polyethylene glycol-based PROTAC linker featuring a terminal carboxylic acid for controlled conjugation and a methylamino handle that can support amide or related coupling strategies. Its flexible, hydrophilic PEG architecture helps tune linker length and conformational freedom, which can improve ternary complex formation and targeted protein degradation performance in PROTAC workflows. The following sections describe the molecule’s structure and the practical reactivity considerations for PROTAC assembly in detail below.

Structure: The linker comprises a PEG repeat unit providing a flexible, water-compatible scaffold, terminated by a carboxylic acid and substituted with a methylamino group. It contains ether linkages within the PEG chain and functional groups suitable for amide bond formation, enabling stable conjugation chemistry.

Reactivity: The terminal carboxylic acid is typically activated for coupling to amine-containing warheads or ligands using standard peptide-coupling approaches, such as carbodiimide-mediated activation with additives that suppress side reactions. The methylamino group can participate in nucleophilic acyl substitution to form amides when paired with activated carboxylic derivatives. Mild, aqueous-organic solvent systems and controlled pH are commonly used to maintain linker integrity and minimize hydrolysis.