Chloroacetamido-PEG4-NHS ester linker contains chloroacetamide and NHS ester functional groups. The chloro- is a good leaving group and can undergo substitution reactions. The NHS ester is an active ester which reacts with primary amines to form stable amide bonds. The PEG spacer increases the solubility of the compound in aqueous media.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.