Bis-Mal-Lysine-PEG4-acid

Bis-Mal-Lysine-PEG4-acid, is designed to provide a flexible, water-compatible spacer that can connect two functional handles for multivalent PROTAC assembly. Its PEG-based architecture supports favorable solubility and conformational adaptability, while the maleyl-lysine motif enables controlled conjugation strategies commonly used in targeted protein degradation workflows. The

Structure: The linker contains a PEG4-derived hydrophilic segment that imparts flexibility and aqueous compatibility, flanked by bis-maleimide-reactive lysine-derived functionalities and a terminal carboxylic acid for handle-based coupling. It features amide and ether linkages, with maleimide-type electrophilic centers suitable for selective thio-conjugation.

Reactivity: Suitable PROTAC construction typically relies on thiol–maleimide conjugation under mild, near-neutral conditions to form stable thioether linkages. Reaction progress is commonly monitored by analytical methods, with careful control of thiol equivalents and pH to maintain maleimide reactivity while minimizing side reactions such as hydrolysis. Water-miscible buffers and compatible organic co-solvents are often used, and inert atmosphere is sometimes employed to limit thiol oxidation.