ɑ-Butyric Acid NHS Ester-ω-Tritylmercaptopropanamido PEG

This crosslinking agent is designed to first conjugate an amino substrate via the active ester. Subsequently the thiol functionality is deprotected and used for crosslinking the conjugated molecule to transition metal surfaces like gold/silver or to other thiol specific groups. PEG-NHS ester derivatives are active esters and useful reagents to pegylate proteines, peptides or any other surfaces with a free primary amino group to form stable amide bonds. The Reaction requires a neutral to alkaline pH (7 to 8.5) to proceed. However, hydrolysis competes with aminolysis of the active ester and also increases with higher pH. Thus, working with excess PEG-NHS ester is necessary to obtain high pegylation yields. The PEG butyric acid NHS ester derivative has a C4 chain directly attached to PEG. It is one of the most stable PEG NHS esters known with a hydrolysis half-life of over 20 min at pH 8.