Tr-PEG8-OH

Tr-PEG8-OH, is a polyethylene glycol–based spacer designed to improve solubility, reduce non-specific interactions, and tune the effective distance between a targeting ligand and an E3 ligase recruiter. Its hydroxyl-terminated handle enables convenient conjugation strategies commonly used in targeted protein degradation workflows. The following sections describe the linker’s structure and practical reactivity considerations in more detail.

Structure: Tr-PEG8-OH is a flexible PEG chain bearing a terminal hydroxyl group, providing a hydrophilic, conformationally mobile scaffold. It contains repeating ether linkages that confer water compatibility, while the terminal alcohol offers a reactive functional site for derivatization. Overall, it behaves as a non-rigid spacer.

Reactivity: The terminal hydroxyl supports standard functionalization routes used to assemble PROTAC constructs, including activation to form electrophilic intermediates followed by nucleophilic substitution with complementary amine or heteroatom-bearing partners. Typical approaches employ coupling/activation reagents under anhydrous, inert or controlled conditions, with polar aprotic solvents often used to maintain solubility. Reaction design should account for PEG stability and minimize side reactions such as over-activation.