环-Phe-His二肽水溶液的激光光解

Laser Flash Photolysis Study of Cyclic-Phe-His in Aqueous Solution

报导了利用纳秒级激光光解瞬态吸收光谱技术研究环苯丙氨酰组氨酰水溶液光解和光敏化作用过程.发现了该环肽在248nm激光的激励下产生光电离和光解离,光电离和光解离过程发生在苯丙氨酸残基上,生成具有320nm和410nm特征吸收的自由基,光解离产生具有320nm特征吸收的苄基自由基.而具有亲电子性的丙酮能在该环肽的苯丙氨酸残基的苯环上抽取电子,形成320nm和410nm的特征吸收峰,求出了自由基的有关动力学参数,并用脉冲辐解动态吸收光谱法印证了上述结果.

Photolysis and photosensition of cyclic-phenylalanine-histidine(cyclic-Phe-His) in aqueous solution were studied using KrF laser flash photolysis (248nm).Photoionization and photodissociation of cyclic-Phe-His in Phe-site occured and the charateristic absorption at 320nm and 410nm have been observed.From changes of the absorption peaks and kinetic analysis,the reaction mechanism of photoionization and photodissociation has been suggested,a series of kinetic parameters have been obtained.Using acetone as a photosensitizer,and N3·as an oxidant by pulse radiolysis method,the induced oxidation of cyclic-Phe-His in aqueous solution has been also reported in this paper,results similar to the photoionization of cyclic-Phe-His have been found.