Abstract: The present invention provides a process for the colorimetric determination of an analyte by means of enzymatic oxidation of the analyte in the presence of an electron acceptor and determination of the reduced electron acceptor by color formation as measure for the amount of the analyte, wherein the analyte is oxidized with an appropriate oxidoreductase in the presence of a substance selected from the group of compounds with nitrogen in an oxidation stage between +1 and -1 as direct electron acceptor.The present invention also provides an agent for the colorimetric determination of an analyte by enzymatic oxidation of the analyte, containing an oxidoreductase and a color-forming electron acceptor, wherein the color-forming electron acceptor is a substance reacting directly with the analyte/enzyme system selected from the group of compounds with nitrogen in an oxidation stage between +1 and -1.