mPEG-Iodide

mPEGn-I is commonly employed as a highly reactive alkylating agent for nucleophilic substitution with thiols, amines, or carboxylates, facilitating covalent PEGylation of peptides, proteins, and small molecules. Its key advantages include superior leaving group ability (compared to Br/Cl analogs), tunable PEG length (n), and efficient conjugation under mild conditions, though the iodide group requires protection from light and moisture due to its sensitivity to hydrolysis and decomposition.