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EZ-Link HPDP-Biotin

For reversible biotinylation of cysteine sulfhydryl groups.

EZ-Link HPDP-Biotin

Thermo Scientific EZ-Link HPDP-Biotin is pyridyldithiol-activated, sulfhydryl-reactive biotinylation reagent that conjugates via a cleavable (reversible) disulfide bond to enable use in a variety of purification methods.

HPDP-Biotin is a pyridyldithiol-biotin compound for labeling protein cysteines and other molecules that contain sulfhydryl groups. This reagent specifically reacts with reduced thiols (-SH) in near-neutral buffers to form reversible disulfide bonds. HPDP-Biotin is useful for labeling and affinity-purification applications that require recovery of the original, unmodified molecule. For example, a protein can be biotinylated, allowed to bind its interactor, then captured to a streptavidin column and finally eluted and recovered by reduction of the disulfide bond with dithiothreitol.


  • Protein labeling – biotinylate antibodies or other proteins for use in protein methods
  • Thiol-reactive – reacts with sulfhydryls (-SH), such as the side-chain of cysteine (C)
  • Pyridyldithiol-activated – perform reactions at pH 6.5 to 7.5 in buffers such as PBS
  • Reversible – forms disulfide bonds, which can be cleaved using DTT or other reducing agent
  • Solubility – must be dissolved in DMSO or DMF before further dilution in aqueous buffers
  • Medium length – spacer arm (total length added to target) is 29.2 angstroms

Product Details:

Chemical structure of HPDP-Biotin
Chemical structure of HPDP-Biotin. This biotinylation reagent labels antibodies and other proteins and molecules that contain sulfhydryl groups (e.g., side-chain of cysteine). The reaction releases pyridine-2-thione, which can be measured spectrophotometrically (Amax = 343nm) to monitor labeling progress. For more information, see our review of Pyridyl Disulfide Reaction Chemistry.

Properties of HPDP-Biotin. This sulfhydryl-reactive compound has a an extended spacer arm and a pyridyldisulfide group that forms reversible disulfide bonds.
Alternative names Biotin-HPDP, pyridyldithiol-biotin, pyridyldisulfide-biotin
Chemical name N-[6-(Biotinamido)hexyl]-3'-(2'-pyridyldithio)propionamide
Molecular formula C24H37N5O3S3
Molecular weight 539.78
Spacer arm length 29.2 angstroms
Mass added to target 428.19 daltons
Form White powder
Storage conditions 4°C, protect from thiols
Reactive groups Pyridyldisulfide, reacts with sulfhydryls at pH 6.5-7.5
Cleave with 50mM DTT or other reducing agents

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency and performance for the intended research applications.

Biotinylation reagents differ in reactivity, length, solubility, cell permeability and cleavability. Three types of sulfhydryl-reactive compounds are available: maleimido, iodoacetyl and pyridyldithiol. Pyridyldithiol reagents specifically react with sulfhydryl groups (-SH) in near-neutral buffers to form reversible disulfide bonds.

In proteins, sulfhydryls exist where there are cysteine (C) residues. Cystine disulfide bonds must be reduced to make sulfhydryl groups available for labeling. Hinge-region disulfide bridges of antibodies can be selectively reduced to make functional half-antibodies that can be labeled.


  • Retrieve cell surface receptors and cleave the biotin away on an immobilized avidin column (Ref.1)


  1. Ghebrehiwet, B., et al. (1988). J.Immunol.Meth. 110, 251-260
  2. Horney, Mark J., et al. (2001) J. Biol. Chem. 276, 2880-2889.
  3. Slatin, S.L., et al. (2002) Proc. Natl. Acad. Sci. 99, 1286-1291.

Related Resources:

Biotinylation Reagents Selection Guide
Review of Biotinylation Methods and Applications
Chemistry of Crosslinking (and Labeling Reagents)

Related Products:

All Biotinylation Reagents
Biotin Quantitation Reagents and Kits
Avidin, Streptavidin, NeutrAvidin Affinity Resins

Ordering Information
Product # Description Pkg. Size Instructions MSDS CofA Price
21341 EZ-Link HPDP-Biotin
Formulation: Pyridyldithiol-activated biotin with a hexylenediamine spacer
Sufficient For: Approx. 25 uses to label a total of 232mg of IgG using typical conditions
50mg Product Instructions for product #21341 EZ-Link HPDP-Biotin MSDS for product #21341 EZ-Link HPDP-Biotin Certificate of Analysis for product #21341 EZ-Link HPDP-Biotin $268.00

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Instructions | MSDS | CofA
Product Instructions | MSDS | CofA  

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