Collection: PEG NHS Ester

PEG NHS esters, a category of amine-reactive PEG reagents, are widely employed in the bioconjugation process with antibodies (ADC), proteins, peptides, and various molecules. Their notable attributes include ease of preparation, reactivity, selectivity, stability for storage, and functionality in aqueous environments. These esters engage in the formation of stable and irreversible amide bonds with primary amines (-NH2) present on proteins, peptides, antibodies, and other molecules or surfaces.

The reaction is conducted within the pH range of 7 to 9, with the optimal pH falling between 8.3 and 8.5. In this process, primary amines act as nucleophiles, attacking the NHS ester and releasing NHS as a byproduct. It is noteworthy that the NHS ester can undergo hydrolysis in aqueous solutions, which competes with the amine reaction and becomes more pronounced at higher pH levels.

Proteins, including antibodies, often feature multiple primary amines on their lysine (K) residues and N-termini of each polypeptide chain, making them suitable targets for PEG NHS ester labeling. This capability facilitates swift and straightforward surface modification of these biomolecules, presenting significant utility in applications such as targeted drug delivery.