Thermo Scientific EZ-Link Sulfo-NHS-LC-Biotin is an intermediate-length, water-soluble biotinylation reagent for labeling antibodies, proteins and other molecules that have primary amines.

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

• Protein labeling—biotinylate antibodies to facilitate immobilization, purification or detection using streptavidin resins or probes
• 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
• Soluble—charged sulfo-NHS group increases reagent water solubility compared to ordinary NHS-ester compounds
• Irreversible—forms permanent amide bonds; spacer arm cannot be cleaved
• Medium length—spacer arm (total length added to target) is 22.4 angstroms; provides excellent balance between adequate length (minimal steric hindrance for biotin binding) and modest mass

Sulfo-NHS-LC-Biotin is one of three very similar EZ-Link Reagents that are water-soluble, non-cleavable, and enable simple and efficient biotinylation of antibodies, proteins and any other primary amine-containing macromolecules in solution. Specific labeling of cell surface proteins is another common application for these uniquely water-soluble and membrane impermeable reagents. Differing only in their spacer arm lengths, the three Sulfo-NHS-ester reagents offer the possibility of optimizing labeling and detection experiments where steric hindrance of biotin binding is an important factor. Sulfo-NHS-LC-Biotin is offered in several package sizes and as complete protein labeling kits.

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.