A tentacle gel simplifies the purification of ceruloplasmin

The mechanism of how chloroethylamine-treated agarose greatly simplifies the purification of ceruloplasmin (Cp) by preferentially binding this protein from blood plasma has been investigated. Chloroethylamine readily cyclizes to ethylenimine under alkaline conditions which then polymerizes to polyethylenimine (PEI). Ethylenimine and PEI were detected in the reaction mixture used to generate the resin. PEI polymers are grown from the matrix and form "tentacle" ligands, while PEI-silica and PEI-cellulose which are not tentacle gels did not bind Cp as readily. Spermine and spermidine, naturally occurring polyamine compounds, were attached to CNBr activated-agarose and showed weak affinity for Cp. [It should be noted that ethylenimine is a potential human carcinogen and presents an inhalation hazard.]