EFFECT OF SOME POLY(ETHYLENE-GLYCOL)-BOUND AND DEXTRAN-BOUND AFFINITYLIGANDS ON THE PARTITION OF SYNAPTIC-MEMBRANES IN AQUEOUS 2-PHASE SYSTEMS

Ligands with an apparent affinity for various structural elements on t he surface of synaptic membrane fragments have been bound to the polym ers poly(ethylene glycol) and dextran. The ligand-polymer derivatives have been included in aqueous two-phase systems composed of water, pol y(ethylene glycol) and dextran. The uneven distribution of the polymer s resulted in the concentration of the polymer-bound ligand in one of the two phases. The effect of the ligand-polymer on the partition of m embranes was studied by using synaptic membranes from calf brain, obta ined by standard centrifugation methods. By using ligand-containing tw o-phase systems for nine-step counter-current distribution of membrane s, it was shown that the distribution behaviour of various parts of th e membrane preparation could be affected. The distribution was followe d by determination of opiate binding, acetylcholinesterase, and total membrane (using protein and light-scattering measurements).