ɑ-Butyric Acid NHS Ester-ω-Propargylacetamido PEG

PEGylation reagent for "Click" Chemistry. This PEG crosslinking reagent with a terminal alkyne functionality on one chain end reacts with azides under "Click" Chemistry conditions (for example Cu(I) catalyzed alkyne-azide cycloaddition, CuAAC) to form a stable triazole link between the two reaction partners. 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.