Amino-PEG-CH2COOH is a molecule composed of a polyethylene glycol (PEG) chain with an amino group and a carboxylic acid functional group attached to it. This molecule belongs to a class of compounds called PEGylation agents, which are widely used in pharmaceutical research and development. PEGylation refers to the covalent attachment of PEG chains to drugs or biomolecules, which can improve their pharmacokinetic and pharmacodynamic properties, such as increasing their solubility, stability, and half-life. Amino-PEG-CH2COOH is particularly useful in the synthesis of PEGylated proteins, peptides, and small molecules, as it can react with primary amines or carboxylic acids in the target molecule to form stable amide bonds. This allows researchers to precisely control the degree and site of PEGylation, which can influence the efficacy and safety of the final product.