Biotin-PEG2-NH-Mal linker contains a biotin group and a maleimide group. The maleimide group specifically labels and crosslinks with cysteines and other sulfhydryls (at pH 6.5-7.5) and form a stable, irreversible thioether bond. The hydrophilic PEG spacer can increase aqueous solubility of the biotin conjugated molecules. It also can also help minimize steric hindrance and provide extra flexibility with the binding to stravidin and avidin molecules.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.