N-hydroxylsuccinimide (NHS) functionalized polyethylene glycol (PEG-NHS) is an amino (-NH2) reactive PEG derivative that can be used to modify protein, peptide or any other surfaces with their available amino groups. NHS esters react with primary amine groups at pH 7~8.5 to form stable amide bonds.Compared to other PEG NHS ester derivatives, our succinimidyl carbonate (SC) functionalized mPEG-NHS offers superior reactivity and higher stability in aqueous solution. NHS esters react with deprotonated primary amines, therefore, the reaction requires neutral to basic pH values to proceed. Primary amines react with NHS esters by nucleophilic attack and NHS is released as a byproduct. Hydrolysis of the NHS-ester competes with the reaction in aqueous solution and increases with increasing pH.
- Off-white/white solid or viscous liquid depends on molecule weight;
- Soluble in regular aqeous solution as well as most organic solvents;
- Store at -20 0C, desiccate. NHS PEG tends to hydrolyze from moisture. Avoid frequent thaw and frozen.
Generally, a 10 to 50-fold molar excess of NHS PEG over the amount of amine-containing material results in sufficient conjugation.
- Conjugation buffer: Sodium bicarbonate 100 mM buffer, pH 8.5 or other amine-free buffer at pH 7-8.5.
- PEG NHS stock solution: 100 mg in 1 mL conjugation buffer.
- Washing solution: Distilled water or any aqueous buffer.
Dissolve targeted materials in conjugation buffer. Estimate the concentration of primary amine groups on the targeted materials. Add NHS PEG stock solution to the targeted conjugation materials with the final concentration keep at least 10 mg/mL. 10~50 molar excess of PEG NHS needed for optimal conjugation; Allow mixture agitates at room temperature for 30~60 min at room temperature or 2 hours at 4 0C. Conjugates can be purified either by size exclusion chromatography or dialysis.