DSPE-PEG-Amine, MW 5000 (ammonium), is a phosphatidylethanolamine that plays a role in the synthesis of liposomes for delivery systems. The amine group in DSPE-PEG-Amine, MW 5000 (ammonium) can be transformed into an aromatic aldehyde, which reacts with acetone-protected aromatic hydrazine on the surface of bovine carbonic anhydrase (BCA) molecules. The liposomes form bisaryl hydrazone (BAH) conjugates with the target enzyme molecules, resulting in liposome-BAH-BCA conjugates that can catalyze the hydration of carbon dioxide into bicarbonate.