NH2-PEG-NH2 (MW 2000) is a polyethylene glycol derivative featuring two primary amine groups. These amine groups readily react with activated carboxylic acids or carboxyl groups (such as NHS esters) to form stable amide bonds. The PEGylation with NH2-PEG-NH2 enhances solubility and stability while reducing the immunogenicity of peptides and proteins. As a result, it is primarily utilized for the modification of proteins, peptides, and other substances.