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SPDP-dPEG®₃₆-NHS ester (QBD-10867)



SPDP-dPEG®36-NHS ester, product number QBD-10867, is a long (115 atoms), hydrophilic, non-immunogenic, heterobifunctional crosslinker that has the same functionality as the widely popular, but unfortunately hydrophobic, SPDP crosslinker. It contains an amine-reactive N-hydroxysuccinimidyl (NHS) ester on one end of the dPEG®36 linker and a thiol-reactive SPDP (also known as OPSS) reactive group on the other end. The long spacer arm may facilitate the reaction of the SPDP end of the molecule with buried thiol groups.

Among the most popular heterobifunctional crosslinking reagents used in bioconjugate chemistry are those compounds that conjugate molecules containing free amine groups with molecules that contain sulfhydryl groups. SPDP (N-succinimidyl 3-(2-pyridyldithio)-propionate) is one of the most popular versions of this type of crosslinker. Unfortunately, SPDP and its popular varieties (LC-SPDP and Sulfo-LC-SPDP) are hydrophobic molecules. When conjugated to biomolecules, care must be taken not to modify the target molecules too much, because this can precipitate the conjugate products.

By contrast, SPDP-dPEG®36-NHS ester, product number QBD-10867, is used like SPDP and its related hydrophobic products to modify peptides, proteins, and other biomolecules. However, precautions against overly modifying the target molecule are not necessary. The water-soluble dPEG® product will not cause the resulting conjugates to precipitate due to excessive hydrophobicity.


Unit Size100mg, 1000mg
Molecular Weight1969.33; single compound
Chemical formulaC₈₇H₁₆₁N₃O₄₁S₂
Purity> 98%
SpacersdPEG® Spacer is 115 atoms and 137.8 Å
Typical solubility properties (for additional information contact Customer Support)Methylene chloride, Acetonitrile, DMAC or DMSO.
Storage and handling-20°C; Always let come to room temperature before opening; be careful to limit exposure to moisture and restore under an inert atmosphere; stock solutions can be prepared with dry solvent and kept for several days (freeze when not in use). dPEG® pegylation compounds are generally hygroscopic and should be treated as such. This will be less noticeable with liquids, but the solids will become tacky and difficult to manipulate, if care is not taken to minimize air exposure.


Greg T. Hermanson, Bioconjugate Techniques, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0); See pp. 276-335 for general description and use of heterobifunctional crosslinkers, and the specific sample protocol for SPDP and LC-SPDP on pp. 286-288. See Greg’s extensive index on pp. 1192-1193 for references to a number and range of applications and their respective protocols.

Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition, Elsevier, Waltham, MA 02451, 2013, ISBN 978-0-12-382239-0; See Chapter 18, Discrete PEG Reagents, pp. 787-821, for a full overview of the dPEG® products.

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