Thalidomide-5-(PEG4-acid) is thalidomide acid derivative. It is commonly used as a precursor to PROTAC that hijacks cereblon as the E3 ubiquitin ligase component. The carboxylic acid group readily conjugate with a linker/target protein ligand.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.