A synthetic genetic circuit has been designed whose topology and function echo those of an electronic inverting amplifier. Several variants of this circuit have been built in our laboratory. This paper reports on the testing of one of these variants and contributes to the field both in terms of evaluating the specific amplifier performance and in terms of providing a methodology for performance evaluation of analog genetic circuits. An input source was created and partially calibrated. It was then used to test the circuit through both fluorometer measurements and flow cytometry. In the discussion, consideration is given to cellular loading by the synthetic circuits and the resulting impact on circuit performance. Models developed earlier are compared with the experimental results. The circuit does indeed perform as an inverting amplifier.