Characteristics analysis of bacteriorhodopsin under irradiation of strong and weak light in turn

Abstract：Characteristics of bacteriorhodopsin under strong and weak light irradiation were studied and analyzed.The simplified energy level diagram and rate equations were established based on the photocycle of bacteriorhodopsin, and the molecule number concentration and its variation rule of the most important and longest lifetime at upper-energy state were obtained by solving the rate equations.It was found that the molecular number concentration at the upper-energy stateM¯¯¯Μ¯under the srong light irradiation tended to saturation with time, the rate of rise was faster as the increase of light intensity, and it gradually returned to ground state after the strong light was stopped.When the bacteriorhodopsin was irradiated with weak light at once, the molecule number concentration at the upper-energy stateM¯¯¯Μ¯was affected by the slow attenuation after the strong light irradiation and the increase caused by the weak light irradiation.With the extension of time, the molecule number concentratio at upper-energy stateM¯¯¯Μ¯was mainly affected by weak light irradiation.The main component of human eye's rod cells is rhodopsin, and its molecular structure and characteristics are basically the same as those of bacteriorhodopsin.The results of the study could be used to explain the dark adaptation characteristics of human eyes.

Keyword：bacteriorhodopsin;photocycle;energy level;relative molecule number concentratio;rhodopsin;