Maleimide-PEG₈-NHS ester (CAS 756525-93-6)

Maleimide-PEG8-NHS ester is a specialized compound frequently used in the area of bioconjugation, which plays a crucial role in biochemical and biophysical research. This compound incorporates three functional groups: maleimide, a polyethylene glycol (PEG) chain consisting of eight ethylene glycol units (PEG8), and an N-hydroxysuccinimide (NHS) ester, each contributing distinct properties that facilitate its use in modifying and connecting biomolecules. The NHS ester portion of Maleimide-PEG8-NHS ester allows for efficient and selective conjugation to primary amine groups, such as those found on lysine residues within proteins or on the N-termini of peptides. This reaction forms stable amide bonds, anchoring the molecule to amines in a highly specific manner under mild conditions. This property is crucial for the covalent attachment of PEG chains and maleimide groups to biomolecules for further functionalization. Maleimide is notably reactive towards thiol groups, often present in cysteine residues of proteins. This reactivity makes it valuable for forming stable thioether bonds that are resistant to hydrolysis, thus facilitating the targeted conjugation of thiol-containing molecules. The PEG8 spacer in the molecule enhances several key properties of the conjugates, including solubility in aqueous environments, reduced aggregation, and minimized immunogenicity of attached bioactive compounds. The presence of PEG also provides a flexible and inert linker that can improve the biophysical properties of conjugated molecules, such as proteins and peptides.