Biotin-HPDP is a sulfhydryl-reactive biotinylation reagent that forms a reversible disulfide linkage. It is used to label protein cysteines and other substrates that contain sulfhydryl groups. Biotin-HPDP is also used in the biotin switch technique to tag S-nitrosylated (SNO) proteins, following reduction of SNO groups to thiols. Compounds that are tagged with biotin interact avidly with streptavidin-coupled beads, fluorophores, enzymes, etc. The interaction of biotin-HPDP with substrates containing sulfhydryl groups is easily performed at pH 6.5 to 7.5 in buffers such as PBS. The disulfide linkage that is formed between avidin and substrate can later by cleaved by a reducing agent, like dithiothreitol.
