The carboxy-PEG_n-amine (CA[PEG]n) PEGylation reagents are zwitterionic, amino acid derivatives that are used for modifying proteins or surfaces such as beads, nanoparticles and self-assembled monolayers. These PEGylation reagents are homogenous compounds of defined molecular weight and spacer length, providing precision in optimising modification applications.

• Provided as a series of 4, 8, 12 and 24 ethylene glycol units, enabling modification procedures to be optimised for a specific application
• PEG spacer provides unique advantages, including increased stability, reduced tendency toward aggregation and reduced immunogenicity
• Allows site-specific labeling or crosslinking involving primary amines or carboxyl groups on proteins or surfaces
• Easy-to-follow instructions increase the likelihood of a successful outcome

CA(PEG)n is the abbreviation for a set of compounds having polyethylene glycol (PEG) spacers with carboxy (-COOH) and amino (-NH₂) termini. The unbranched, hydrophilic, discrete-length molecules have the form Carboxy-PEGn-Amine, where the subscript 'n' denotes 4, 8, 12, or 24 ethylene glycol units. The carboxyl and primary amine of each compound provide specific targets for crosslinking and other conjugation methods, making these compounds useful as PEGylation reagents.