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EZ-Link NHS-SS-Biotin

Membrane-permeable and cleavable for intracellular, reversible biotinylation.

EZ-Link NHS-SS-Biotin

Thermo Scientific EZ-Link NHS-SS-Biotin enables simple and efficient biotinylation of antibodies, proteins and other primary amine-containing molecules, as well as intracellular labeling.

NHS-SS-Biotin is succinimidyl 2-(biotinamido)-ethyl-1,3' -dithiopropionate, a compound that enables simple and efficient biotinylation of antibodies, proteins and other primary amine-containing molecules. The extended spacer arm (24.3 angstroms) of this reagent reduces steric hindrance associated with binding to avidin or other biotin-binding proteins and incorporates a reducing agent-cleavable disulfide bond (-S-S-) within the spacer, providing further versatility to the reagent.


  • Protein labeling – biotinylate antibodies or other proteins for detection or purification using streptavidin probes or resins
  • Membrane-permeable – can be used to label inside cells (intracellular)
  • Amine-reactive – reacts with primary amines (-NH2), such as the side-chain of lysines (K) or the amino-termini of polypeptides
  • Cleavable – disulfide bond in spacer arm allows the biotin label to be removed using reducing agents such as DTT; only a small sulfhydryl group remains attached to the molecule
  • Solubility – must be dissolved in DMSO or DMF before further dilution in aqueous buffers
  • Medium length – spacer arm (total length added to target) is 24.3 angstroms; it consists of the native biotin valeric acid group extended by a 7-atom chain

Product Details:

Chemical structure of NHS-SS-Biotin Chemical structure of NHS-SS-Biotin. This biotinylation reagent labels antibodies and other proteins and molecules that contain primary amines (e.g., side-chain of lysine). For more information, see our review of NHS Ester Reaction Chemistry.

Properties of NHS-SS-Biotin. This amine-reactive compound has a cleavable disulfide bond and is cell membrane permeable. Cleavable compounds that are not membrane permeable also exist.
Molecular formula C19H28O6N4S3
Molecular weight 504.65
Spacer arm length 24.3 angstroms
Mass added to target 389.56 daltons
Form White to off-white powder
Storage conditions -20°C with desiccant, protect from moisture, use only fresh solutions
Reactive groups N-hydroxysuccinimide ester, reacts with primary amines at pH 7.0-9.0
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.

N-Hydroxysulfosuccinimide (NHS) esters of biotin are the most popular type of biotinylation reagent. NHS-activated biotins react efficiently with primary amino groups (-NH2) in alkaline buffers to form stable amide bonds. Proteins (e.g., antibodies) typically have several primary amines that are available as targets for labeling, including the side chain of lysine (K) residues and the N-terminus of each polypeptide.

Varieties of biotin NHS-ester reagents differ in length, solubility, cell permeability and cleavability. Non-sulfonated NHS-biotins are cell permeable but must be dissolved in organic solvent such as DMSO or DMF. Sulfo-NHS biotins (and those with pegylated spacers) are directly water soluble but not membrane permeable. Varieties containing disulfide bonds can be cleaved using reducing agents, enabling the biotin group to be disconnected from the labeled protein.

Related Resources:

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

Related Products:

Pierce Cell Surface Protein Isolation Kit
All Biotinylation Reagents
Avidin, Streptavidin, NeutrAvidin Affinity Resins

Ordering Information
Product # Description Pkg. Size Instructions MSDS CofA Price
21441 EZ-Link NHS-SS-Biotin
Formulation: NHS ester of biotin with an ethyl-1,3-dithioproprionate spacer
Sufficient For: Approx. 25 uses to label a total of 661mg of IgG using typical conditions
50mg Product Instructions for product #21441 EZ-Link NHS-SS-Biotin MSDS for product #21441 EZ-Link NHS-SS-Biotin Certificate of Analysis for product #21441 EZ-Link NHS-SS-Biotin $241.00

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Instructions | MSDS | CofA
Product Instructions | MSDS | CofA  

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