Three-dimensional superstructures, multilayer-arrays consisting of Au-nanoparticles (13 +/- 1 nm) and crosslinked by microperoxidase-11 (MP-11), were assembled on transparent ITO conductive glass supports. The structures of the assemblies were confirmed by spectroscopic and electrochemical analyses, which revealed that each Au-particle is associated with ca. 50 MP-11 molecules. The multilayered MP-11/Au-particle systems act as electrocatalysts for the reduction of H2O2. The number of MP-11 / Au-particle layers associated with the electrode controls the resulting electrocatalytic currents. The controllable number of MP-11 / Au-particle layers associated with the electrode enables the control of the effectiveness of the electrocatalytic process and tuning of the sensitivity of the H2O2-sensing interface.