Conjugation of DSPE-PEG NHS ester to amine of antibody
The carboxylic acid on the phospholipid can be converted to a N-Hydroxysuccinimide (NHS) ester which can be further conjugated to a free amine on an antibody. This single step leads to the formation of a stable amide linkage. NHS ester is perhaps the most common activation chemistry for creating reactive acylating agents. The NHS ester derivative reacts with nucleophiles such as primary amine with release of the NHS leaving group to form a stable amide bond containing product. In protein, NHS ester reagents couple principally with alpha amines at the N terminal and the beta amines of lysine side chains. Sulfhydryl and hydroxyl groups can also react with such active esters but the products of such reactions , thioesters and esters, are unstable in aqueous environments or in the presence of amine nucleophiles.
Hydrolysis and amine reactivity both increase with increasing pH. The rate of hydrolysis may be monitored by measuring the increase in absorptivity at 260 nm as the NHS leaving group is cleaved. To maximize the modification of amines and minimize the effects of hydrolysis, maintain a high concentration of protein or other target molecule in the reaction medium. NHS ester can be formed by first activating the carboxylate using EDC which then can be transformed to an active ester by reaction in presence of NHS.
Antibody Liposome Conjugation: Using NHS activated Lipids
Copyright by Encapsula NanoSciences 2014
Use this form to find things you need on this site