CNBractivated

CNBr-activated refers to a class of immobilized resin materials, most commonly CNBr-activated Sepharose, that have been chemically treated with cyanogen bromide to present reactive groups on the matrix. The activated surface carries cyanate ester and imidocarbonate groups capable of reacting with primary amines on proteins, peptides, or other nucleophiles to form covalent bonds, enabling irreversible immobilization of the target molecule onto the solid support.

In practice, proteins or other amine-containing molecules are incubated with the CNBr-activated resin under mild alkaline conditions. Amino groups such as N-terminal amines and lysine side chains react with the activated groups to form covalent linkages, typically through urethane or related linkages. After coupling, unreacted active groups are commonly quenched with a small nucleophile such as ethanolamine to reduce non-specific binding. The resulting immobilized product is stable under typical chromatographic conditions, though the linkage is not orientation-specific and can affect protein activity if critical sites are involved.

Applications of CNBr-activated resins include affinity chromatography, enzyme immobilization, antibody coupling, and various immunoassays. They are valued for enabling straightforward covalent attachment of proteins to a solid support, facilitating reusable columns and stable immobilized reagents. Selection of CNBr-activated resins involves considerations of protein size, available lysine residues, desired binding density, and potential impact on protein activity.

Safety and handling: cyanogen bromide is highly toxic and volatile; operations must be conducted in a well-ventilated fume hood with appropriate personal protective equipment and waste disposal procedures. Storage typically keeps the resin moist and in accommodates a suitable buffer at refrigerated temperatures, with blocking steps performed after coupling to minimize non-specific interactions.