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LC-SPDP (succinimidyl 6-[3(2-pyridyldithio)propionamido]hexanoate)

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Long chain-SPDP, N-[6-[(2,5-dioxo-1-pyrrolidinyl)oxy]-6-oxohexyl]-3-(2-pyridinyldithio)propanamide
Empirical Formula (Hill Notation):
C18 H23 O5 N3 S2
CAS Number:
Molecular Weight:
MDL number:
PubChem Substance ID:



Quality Level



mol wt


reaction suitability

reagent type: cross-linking reagent

storage condition



DMSO or DMF: soluble

functional group

NHS ester

shipped in


storage temp.


SMILES string




InChI key


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General description

The amine-reactive portion of SPDP reagents is the N-hydroxysuccinimide (NHS) ester. Reactions are most commonly performed in phosphate, carbonate/bicarbonate, or borate buffers at pH 7-8. Other buffers can be used provided they do not contain primary amines (or thiols or disulfide reducing reagents – see discussion of the sulfhydryl reactivity). The rate of reaction and degradation by hydrolysis increases with increasing pH; for example, the half-life of the NHS ester is several hours at pH 7 and less than 10 minutes at pH 9. NHS-ester reagents like SPDP and LC-SPDP have limited aqueous solubility and must be dissolved in organic solvent before adding them to a reaction mixture. Sulfo-NHS-ester reagents like Sulfo-LC-SPDP are water-soluble and can be added directly to aqueous reaction mixtures.

Features and Benefits

  • Reactive groups: NHS ester and pyridyldithiol
  • Reactive towards: amino and sulfhydryl groups
  • Releases a detectable by-product when reacted with a free sulfhydryl group; by measuring the release of pyridine-2-thione at 343 nm, the reaction can be easily followed
  • Disulfide bond in the spacer arm is readily cleaved by 10-50 mM DTT or TCEP at pH 8.5
  • Spacer arm is also easily cleaved using reducing SDS-PAGE sample loading buffer
  • Cleavable crosslinker allows separation of crosslinked products
  • Water-insoluble (dissolve first in DMF or DMSO)
  • SPDP crosslinker is membrane permeable, so crosslinking can be done inside the cells
  • Compare to other varieties of SPDP-type reagents, including pegylated forms


This product is sensitive to moisture. The vial is packaged in a resealable bag with a desiccant to reduce exposure to moisture. After cold storage, equilibrate the vial to room temperature before opening to reduce condensation inside the vial. Make fresh solutions. Storage of stock solutions is not recommended. After use, return the vial to the resealable bag. Close the bag and store the product at the recommended temperature.

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

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A solid-phase enzyme-linked immunoassay using a fluorogenic substrate (4-methylumbelliferyl-beta-D-galactopyranoside) was developed. Antibodies were covalently linked to glutaraldehyde-activated 96-well aminopolystyrene plates. Antigens from test samples were adsorbed to the solid phase and detected using antibodies conjugated with E. coli beta-galactosidase. Glutaraldehyde
J Carlsson et al.
The Biochemical journal, 173(3), 723-737 (1978-09-01)
A heterobifunctional reagent, N-succinimidyl 3-(2-pyridyldithio)propionate, was synthesized. Its N-hydroxysuccinimide ester group reacts with amino groups and the 2-pyridyl disulphide structure reacts with aliphatic thiols. A new thiolation procedure for proteins is based on this reagent. The procedure involves two steps.

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