The acid NHS ester can be used to conjugate with amine-bearing biomolecules such as lysine residue on the proteins and amine modified oligonucleotide and biopolymers. The pyridyldithiol reactive groups can react cysteine sulfhydryls with to form cleavable (reducible) disulfide bonds, which makes it an ideal conjugate tool for cysteine residues.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.