KEY FEATURES: ? SPDP contains a dithiopyridyl group which is reactive towards cysteines (-SH groups) and an NHS group, which is useful when targeting primary amines (-NH2 groups) ? SPDP releases a byproduct, pyridine-2-thione after reacting with free sulfhydryl groups. By measuring the release of this byproduct at 343 nm, the reaction can be easily followed ? Contains a disulfide linkage in its spacer arm with a length of 6.8 A? ? The spacer is cleavable with reducing agent, such as DTT, TCEP, etc. APPLICATIONS: ? Reversible crosslinking of proteins ? N-hydroxysulfosuccinimide (Sulfo-NHS) ester that reacts with primary amines, as found in lysine side chains ? Useful for adding sulfhydryl groups to proteins