Maleimide functionalized polyethylene glycol, Maleimide PEG is a sulfhydryl (thiol/SH) group reactive PEG derivative that can be used to selectively modify protein, peptide or any other surfaces with availablesulfhydryl groups. The reaction between maleimide and thiol proceeds readily at pH 6.5~7.5 to form stable thioether bonds. Maleimide functionalized polyethylene glycol, Maleimide PEG is a sulfhydryl (thiol/SH) group reactive PEG derivative that can be used to selectively modify protein, peptide or any other surfaces with availablesulfhydryl groups. The reaction between maleimide and thiol proceeds readily at pH 6.5~7.5 to form stable thioether bonds. application： Applicated in medical research, drug-release, nanotechnology and new materials research, cell culture. In the study of ligand, polypeptide synthesis support, a graft polymer compounds, new materials, and polyethylene glycol-modified functional coatings and other aspects of the active compound.