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EZ-Link Biocytin

Useful for synthesizing long-chain biotinylation reagents.

EZ-Link Biocytin

Thermo Scientific EZ-Link Biocytin is a simple variant of biotin that contains a primary amine in its valeric acid chain, which provides the essential backbone for construction of certain long-chain and trifunctional biotinylation reagents.

Biocytin is ε-N-[d-biotinyl]-L-lysine, a compound formed by conjugation of the epsilon amine of lysine to the valeric acid side chain of biotin. It contains terminal carboxyl and amino groups, which provide functional handles for derivatization or conjugation to proteins, surfaces and other molecules. Carbodiimide (EDC) and NHS-ester crosslinker chemistries are most often utilized for covalent modifications involving biocytin. The compound is also useful as an amino acid control or biotin standard in assay methods involving streptavidin binding.


  • Biotinylation – label molecules and surfaces for assays or affinity purification methods involving avidin or streptavidin probes and resins
  • Amine-activated – primary amine can be crosslinked to proteins and material surfaces using EDC and other crosslinkers
  • Lysine derivative – functions as a biotin-tagged amino acid; potentially useful as a control or quenching reagent in biotin assay methods
  • Medium length – spacer arm (total length added to target) is 20.1 angstroms, representing a 7-atom extension of the native biotin valeric acid

Product Details:

Chemical structure of Biocytin
Chemical structure of Biocytin. Carboxyl- and/or amine-terminated biotinylation reagents such as this one are often conjugated using the crosslinker EDC. For more information, see our review of Carbodiimide Reaction Chemistry.

Properties of Biocytin.
Alternative names Biotin-lysine
Chemical name ε-N-[d-biotinyl]-L-lysine
Molecular formula C16H28N4O4S
Molecular weight 372.48
Spacer arm length 20.1 angstroms
CAS number 576-19-2
Form White powder
Storage conditions Room temperature

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

Amino-biotin compounds can be conjugated to functional groups of proteins and other molecules in a variety of ways. The most common method is to crosslink the terminal primary amine to carboxyl groups using EDC carbodiimide crosslinker chemistry. Carboxyl groups (-COOH) occur in aspartate or glutamate residues and the carboxy-terminus of polypeptides. When activated with EDC (Part No. 22890), carboxylates react with amino (–NH2) groups to form amide bonds.

Biocytin has both carboxyl and amino groups. Therefore, to prevent self-conjugation of biocytin, EDC-mediated reaction schemes with this compound are usually done in two steps, aided by Sulfo-NHS (Part No. 24510): (1) Activate a carboxylate molecule using EDC and Sulfo-NHS, followed by complete removal or inactivation of the EDC reagent; then (2) Add Biocytin to allow its primary amine to react with the Sulfo-NHS ester-activated carboxyl groups. See NHS-ester Chemistry. Subsequently, the remaining carboxyl group of biocytin could be conjugated to yet another molecule. For example, biocytin is the starting material for synthesis of Sulfo-SBED (Part No. 33033), a trifunctional reagent.


  1. Baqui, M., et al. (2003) J. Biol. Chem. 278, 1206-1211.

Related Resources:

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

Related Products:

EDC (1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide Hydrochloride)
All Biotinylation Reagents
Avidin, Streptavidin, NeutrAvidin Affinity Resins

Ordering Information
Product # Description Pkg. Size Instructions MSDS CofA Price
28022 EZ-Link Biocytin
Formulation: epsilon-N-Biotinyl-L-Lysine
Sufficient For: 27mL of 10mM solution
100mg Product Instructions for product #28022 EZ-Link Biocytin MSDS for product #28022 EZ-Link Biocytin Certificate of Analysis for product #28022 EZ-Link Biocytin $214.00

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Instructions | MSDS | CofA
Product Instructions | MSDS | CofA  

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