[Two types of photoelectric differential responses of bacteriorhodopsin and their mechanisms].

Based on experimental measurement of the pulse response of the bacteriorhodopsin (BR) film photocell, the impact response function of the device is obtained by data fitting with MATLAB software. A simulation system is accordingly built with the SIMULINK module. The output response signals of the BR film photocell under different stepping incident light are calculated based on this simulation system. It is concluded that the differential response described before (which occurs in milliseconds to seconds, outputs a positive pulse when light is on, and outputs a negative pulse when light is off) was not the intrinsic property of the BR molecule, but was partially caused by the measuring circuit. The differential response caused by the intrinsic property of the BR molecule happened in microsecond time scale, and it produced a negative pulse when light is on and a positive pulse when light is off. The mechanisms of the two types of differential responses are discussed.