Biotin-PEG2-iodide contains a biotin and iodo moiety. Biotin is commonly used for protein conjugation and is commonly used with streptavidin and avidin. Iodo is a good leaving group for nucleophilic substitutions. The hydrophilic PEG spacer increases the solubility of a compound in aqueous media.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.