SPDP
SPDP most commonly refers to N-succinimidyl 3-(2-pyridyldithio)propionate, a heterobifunctional crosslinker used in bioconjugation. It enables linking of proteins and other biomolecules by providing two reactive ends: an NHS ester for amine targeting and a 2-pyridyldithio group for thiol interactions. The NHS ester reacts with primary amines, such as lysine residues, to form a stable amide bond, attaching the crosslinker to the protein. The 2-pyridyldithio end can undergo disulfide exchange with free thiols, allowing reversible conjugation and forming a new disulfide bond while releasing 2-thiopyridone as a byproduct.
In practice, SPDP is used to create antibody labeling, protein–protein conjugates, or to link enzymes to targeting
Handling considerations include the reactive NHS ester, which necessitates appropriate personal protective equipment and handling in
See also: heterobifunctional crosslinkers, disulfide-cleavable linkers, protein bioconjugation.