Merck, P3415-100MG, 3-(2-Pyridyldithio)propionic acid N-hydroxysuccinimide ester

3-(2-Pyridyldithio)propionic acid N-hydroxysuccinimide ester (SPDP) is a heterobifunctional cross-linking reagent with amine and sulfhydryl reactivity. It is typically coupled initially to molecules containing primary amines by amide bonds buffered at pH 7.5 (6.5-8.5). Second coupling specific for molecules containing free sulfhydryl by thiol-disulfide exchange buffered at pH 8.0 (7.5-8.5). Alternately, this reagent may be used as a protected thiolating reagent following initial coupling and reduction of linker. It incorporates four atom linker.