【摘要】 采用紫外可见吸收光谱技术和闪光光解技术 ,初步观察了细菌视紫红质 (BR)分子在宽 pH范围 (2 1～12 3)内的特征吸收峰以及M412 的相对浓度和M412 的慢成分半衰期的变化 ,并对其结构和光循环功能进行了讨论 .紫外可见吸收光谱实验结果显示 :pH =5 0～ 10 0时 ,BR最大特征吸收峰值约为 5 6 8nm ;pH <5 0时 ,BR最大特征吸收峰发生红移 ;pH >10 0时 ,BR最大特征吸收峰发生蓝移 .闪光动力学光谱结果显示 :pH为7 3～ 9 5时 ,M412 的相对浓度 (M0 )基本稳定在 0 0 38左右 ;pH <7 3时 ,M0 逐渐减小 ;pH >9 5时 ,M0 明显上升 ,在pH =11 8时达到最大值 0 135 5 ,随后又快速下降 .pH为 2 1～ 7 3时 ,M412 的慢成分半衰期 (ts1/2 )值在 (4 1± 1 1)ms左右 ;pH >7 3时 ,ts1/2 值急剧延长到 4 0 6 77 4ms .推测在高 pH条件下 ,BR分子的光循环有新的路径和机理更多还原

【Abstract】 The changes of bacteriorhodopsins structure and function were monitored by the UV/VIS absorption spectrum technique and the flash photolysis technique over the wide pH range (2 1～12 3). The results of the UV/VIS absorption spectra showed that: 1) the wavelength of the characteristic absorption peak was about 568 nm (pH=5 0～10 0), 2) the red shift of the absorption spectra was observed (pH<5 0) and 3) the blue shift of the absorption spectra was observed (pH>10 0). The results of the flash induced kinetics spectra indicated that: a) M 0 (relative concentration of M 412 ) kept around 0 038 constantly (pH =7 3～9 5); b) M 0 decreased gradually as pH was below 7 3; c) when pH was above 9 5, M 0 increased obviously and reached the maximum 0 1355 (pH =11 8) then dropped down sharply; d) t s 1/2 (halftime of the slow component of M 412 ) was (4 1±1 1)ms approximately (pH=2 1～7 3) and e) t s 1/2 was prolonged to 40 677 4ms sharply (pH>7 3). It can be concluded that under the condition of high pH, the novel pathway and mechanism of bacteriorhodopsins photocyle may exist.更多还原