Nitric-oxide synthase (NOS) is a family of enzymes involved in many intercellular signaling processes. NOS is a key component of many biological processes, including cellular differentiation, immune responses, and signaling; however, it is still poorly understood. By exploring the optical properties of the F161A mutant of cytochrome P450, we are able to better understand the structure and therefore function of NOS. F161A is known to be emissive upon excitation by specific wavelengths. However, emission has never been measured with simultaneous electrochemical stimulation (and hence reduction or oxidization) of the protein. I measured changes in the emission intensity of F161A upon oxidation and reduction of the heme. I found that reduction of the heme from the FeIII state to the FeII yields a less intense light emission, and reoxidation to the FeIII increases the emission intensity.