Description Features and Benefits SPDP-dPEG®12-NHS ester has an amine-reactive N-hydroxysuccinimide (NHS) ester at one end and a sulfhydryl-reactive 2-pyridyldithiol group at the opposite end. This has a single molecular weight PEG spacer arm, which confers greater water solubility to the crosslinker and linked proteins compared to crosslinkers having only hydrocarbon spacers. Protein aggregation and precipitation also are greatly reduced with SPDP-dPEG crosslinkers compared to crosslinkers that have only hydrocarbon spacers. dPEG spacer of specific length (51.3 Å) provides precise distance control between the SPDP moiety and the target molecule. Pyridyldithiol reagents produce disulfide-containing linkages that can be cleaved with reducing agents such as dithiothreitol (DTT). Crosslinking experiments with SPDP reagents are not limited to those involving proteins. Any of a variety of molecules with primary amines and sulfhydryl groups can be modified or crosslinked using SPDP reagents. Legal Information Products Protected under U.S. Patents # 7,888,536 B2 dPEG is a registered trademark of Quanta BioDesign