Bis-PEG4-NHS ester linker contains two NHS ester groups. The PEG spacer increases the aqueous solubility of the resulting compound. The NHS ester can sequentially conjugate with amine containing proteins, oligonucleotides, etc.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.