Among the variety of different polyelectrolytes, sulfonated polyaniline (PASA) is found to be suitable for the construction of electroactive cyt c-containing multilayers. On the surface of gold electrodes subsequently coated with up to 16 alternating layers of cyt c and PASA the immobilized protein is fully electroactive, retains its native structure and can be successfully applied as a sensor for superoxide [1]. Here we present a study of the polyelectrolyte influence on the multilayer formation and redox properties of the assemblies formed. Two different sulfonated polyanilines (PASA1 [2] and PASA2 [3]) have been chemically synthesized, the assembly build-up has been investigated by Quartz Crystal Microbalance (QCM), and characterization of these systems on electrodes has been performed by Cyclic Voltammetry (CV). The chemically synthesized PASA versions differ in the grade of sulfonation, chain length, overall charge and the presence of an additional methoxy group on the aniline ring. The assembly of both polymers with cyt c is successful, which follows from the results of QCM measurements. Electrochemical studies show an increase in amount of electroactive species on the electrode surface with increasing number of layers in both cases. However, in the case of PASA2, which is shorter than PASA1 and has an additional methoxy group in its structure, higher electroactivity of the polyaniline itself has been observed. This may cause side reactions when the system would be applied in sensorics. Multilayer assemblies with PASA1, in contrast, show a behavior dominated by the redox activity of cyt c , which makes them promising for sensor approaches, e.g for superoxide detection. The study demonstrates that several requirements have to be fulfilled in order to obtain functional protein assemblies on electrodes.