The invention relates to a method for identifying an active substance, which modifies an enzymatic characteristic of the SGLT1 protein. According to said method, primary carriers containing the SGLT1 protein in the vicinity of their membranes are provided. The primary carriers are adsorbed on the surface of a biosensor electrode that acts as a secondary carrier. A potential active substance is prepared and is reacted with the SGLT1 protein. The qualitative and/or quantitative influence of the potential active substance is determined by the detection of the electric action of the SGLT1 protein or a modification of said action by means of the biosensor electrode that acts as a secondary carrier, e.g. using an electric current measurement or voltage measurement.
