t-Boc-N-Amido-PEG4-Ms contains a Boc protecting group and a mesyl group. The t-Boc group can be removed under acidic conditions to form free amine, which can be conjugated to caroxylic acid bearing biomolecules through amide coupling. The mesyl group can be easily replaced by thiol and amino group through a nucleophilic substitution. The hydrophilic PEG spacer can increase the water solubility of the compound. PEG spacer increase the water solubility of the resulting compound.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.