Bis-PEG7-NHS ester

This PROTAC linker product, Bis-PEG7-NHS ester, provides a bifunctional polyethylene glycol (PEG) scaffold capped with N-hydroxysuccinimide (NHS) ester groups for efficient conjugation. Its flexible, hydrophilic linker architecture supports favorable solubility and reduced nonspecific interactions in targeted protein degradation workflows. The dual NHS reactivity enables modular assembly of PROTACs by connecting two ligands or a ligand to a scaffold, facilitating systematic optimization. Detailed structural and reactivity guidance is provided below.

Structure: Bis-PEG7-NHS ester is a PEG-based linker containing two NHS ester termini, connected through ether-rich PEG chains. It features amide-forming activated carbonyls and stable ethyl/alkyl substituent environments typical of NHS esters. The overall structure is flexible, water-compatible, and designed for bioconjugation.

Reactivity: The NHS ester groups react with primary amines to form stable amide bonds via nucleophilic acyl substitution. Suitable conditions typically use mildly basic aqueous buffers that preserve NHS ester reactivity while promoting amine nucleophilicity. Common approaches include adding the amine-containing ligand under controlled pH and temperature, using compatible solvents such as aqueous buffer with limited cosolvent if needed. No special catalysts are generally required; reaction monitoring is recommended to manage hydrolysis of NHS esters.