THE EFFECT OF pH ON THE ROTATIONAL DIFFUSION AND PHOTOELECTRICAL RESPONSE OF BACTERIORHODOPSIN
pH对菌紫质分子的旋转运动和光电响应的影响

The rotational diffusion of bacteriorhodopsin reconstituted into DMPC vesicles was measured at different pH by the technique of flash-induced transient dichroism.Photoelectrical response of bacteriorhodopsin was measured at different pH by the planar membrane system (BLM).In the range of pH3 to pH 8.3,no obvious difference of the rotational diffusion of bacteriorhodopsin was observed.Below pH3,there was obvious difference.Above pH 11,no rotational diffusion could be observed.In the range of the pH2 to pH 11,we measured photo-electrical response of bacteriorhodopsin of BLM.with the increase of the pH value,both the photoelectrical response of the fragment and monomer of bacteriorhodopsin changed from fast positive signal (light on) and fast negative signal (light off) to slow positive signal.Above pH 9.4,the photoelectical response (light on) of monomer changed from positive to negative.Above pH 11,no-photoelectric response could be observed.