4arm PEG Vinylsulfone(4arm PEG VS), MW 10K is a 4arm PEG derivative with multiple reactive groups that bind free thiol groups in aqueous buffers at pH 6.5~8.5 at room temperature.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.