This chemical is a bifunctional linker primarily utilized in bioconjugation and protein modification. The maleimide (dioxopyrrole) moiety reacts selectively with thiol groups on biomolecules, such as cysteine residues in proteins or peptides, to form stable thioether bonds, enabling attachment to other substrates or probes. The terminal carboxylic acid group can be activated to form stable amide bonds with primary amino groups (e.g., lysine residues or amines on substrates). This dual reactivity makes it valuable in developing diagnostic assays, drug delivery systems, and targeted therapies. Additionally, its polyethylene glycol (PEG) chain (approximately PEG6) enhances water solubility, biocompatibility, reduces immunogenicity, and improves the pharmacokinetic properties of conjugated molecules, making it a versatile tool in biomedical research and therapeutic applications.