N-Mal-N-bis(PEG2-acid) is a thiol reactive PEG reagent. Maleimide reacts specifically with sulfhydryl groups to form a stable thioether linkage when the pH is between 6.5 and 7.5. The terminal carboxylic acids can react with primary amino groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond. Reagent grade, for research purpose. Please contact us for GMP-grade inquiries.