Schoenlein R W, Peteanu L A, Mathies R A, Shank C V
Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
Science. 1991 Oct 18;254(5030):412-5. doi: 10.1126/science.1925597.
The kinetics of the primary event in vision have been resolved with the use of femtosecond optical measurement techniques. The 11-cis retinal prosthetic group of rhodopsin is excited with a 35-femtosecond pump pulse at 500 nanometers, and the transient changes in absorption are measured between 450 and 580 nanometers with a 10-femtosecond probe pulse. Within 200 femtoseconds, an increased absorption is observed between 540 and 580 nanometers, indicating the formation of photoproduct on this time scale. These measurements demonstrate that the first step in vision, the 11-cis----11-trans torsional isomerization of the rhodopsin chromophore, is essentially complete in only 200 femtoseconds.
利用飞秒光学测量技术已解析出视觉中初级事件的动力学过程。用一个500纳米的35飞秒泵浦脉冲激发视紫红质的11 - 顺式视黄醛辅基，并通过一个10飞秒探测脉冲测量450至580纳米之间吸收的瞬态变化。在200飞秒内，观察到540至580纳米之间吸收增加，表明在此时间尺度上光产物的形成。这些测量结果表明，视觉的第一步，即视紫红质发色团的11 - 顺式----11 - 反式扭转异构化，在仅200飞秒内基本完成。
