Polysulfone as well as commercially available microfiltration polysulfone membranes were metallated using Li-alkyl. By introducing glycidylethers, epoxidized polysulfone and corresponding epoxidized microfiltration membranes were obtained. From the epoxidized polysulfone, asymmetric ultrafiltration membranes were cast. Further reactions consisted of hydrolyzation and reaction with iminodiacetic acid. The addition of copper to these membranes yields affinity membranes. The different membranes were characterized conventionally, and also by their electrokinetic behavior. For the latter purpose streaming potential measurements were performed. By this means the surface properties of the membranes could clearly be depicted. The differences were related to the different functional groups at the membrane surface. The adsorption of human serum albumin onto the membrane completely altered the streaming potential of the membranes. A remarkable difference was found for neutral and charged membranes.