Ms-PEG8-t-butyl ester linker contains a mesyl group and a t-butyl protecting group. The mesyl group can be easily replaced by thiol and amino group through a nucleophilic substitution. Under mild de-protection conditions, the t-butyl ester can be converted to free carboxylic acid for amide coupling with amine-bearing biomolecules. The PEG spacer addes solubility of the compound in aqueous media.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.