Mal-PEG4-t-butyl ester contains a maleimide group and a t-butyl ester group. The PEG spacer increases the aqueous solubility of the resulting compound. The t-butyl protected carboxyl group can be deprotected under acidic conditions. The maleimide group reacts specifically with a thiol group to form a covalent C-S bond, enabling the bioconjugation with a thiol bearing molecules.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.