The Thermo Scientific EZ-Link Sulfo NHS-SS Biotinylation Kit contains sufficient reagents for 8 biotinylation reactions (e.g., 0.05–0.2 mg antibody per reaction). The EZ-Link Sulfo-NHS-SS-Biotin included in the kit is a water-soluble, NHS-ester biotinylation reagent whose spacer arm includes a cleavable disulfide bond for reversible labeling of proteins and cell surface primary amines.

Features of EZ-Link Sulfo-NHS-SS-Biotin:

• Protein labeling – biotinylate antibodies to facilitate immobilization, purification or detection
• Cell surface labeling – biotinylates only surface proteins of whole cells because the negatively charged reagent does not permeate cell membranes
• Amine-reactive—reacts with primary amines (-NH2), such as lysine side-chains, 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
• Soluble – charged sulfo-NHS group increases reagent water solubility compared to ordinary NHS-ester compounds
• 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

Sulfo-NHS-SS-Biotin is a thiol-cleavable amine-reactive biotinylation reagent that contains an extended spacer arm to reduce steric hindrances associated with avidin binding. This reagent is water-soluble, enabling biotinylation to be performed in the absence of organic solvents such as DMSO or DMF for applications that cannot tolerate solvents or are complicated by their inclusion. The compound is particularly useful for labeling and purifying cell surface proteins, because (a) its sulfonate group prevents it from permeating cell membranes and (b) its cleavable spacer arm enables initially biotinylated proteins to be released from streptavidin affinity columns.

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.

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EZ-Link™ Sulfo-NHS-SS-Biotin
EZ-Link™ Sulfo NHS-SS Biotinylation Kit