Photosensitized oxidation of tryptophan and tyrosine by aromatic ketones:A laser flash photolysis study  

作　　者：TANG RuiZhi ZHANG Peng LI HaiXia LIU YanCheng WANG WenFeng 

机构地区：[1]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China [2]Graduate University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Chemistry》2012年第3期386-390,共5页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (21173252)

摘　　要：Photochemical processes of benzophenone （BP） and xanthone （XT） with tryptophan （TrpH） and tyrosine （TyrOH） were stud- ied using the laser flash photolysis technique. It has been observed that the triplet state of BP and XT reacted with TrpH and TyrOH by hydrogen transfer with the formation of BP and XT ketyl radicals and oxidized radicals of Trp＂ and TyrO＇. The re- lated rate constants of these reactions were determined in this paper. The free energy changes （AG） of these reactions suggested that the proposed hydrogen transfer mechanism was thermodynamically feasible. These results provide theoretical foundation for further studying structural effects on the photochemical behaviors of proteins with triplet state BP and XT.Photochemical processes of benzophenone (BP) and xanthone (XT) with tryptophan (TrpH) and tyrosine (TyrOH) were studied using the laser flash photolysis technique.It has been observed that the triplet state of BP and XT reacted with TrpH and TyrOH by hydrogen transfer with the formation of BP and XT ketyl radicals and oxidized radicals of TrpY and TyrOY.The related rate constants of these reactions were determined in this paper.The free energy changes (G) of these reactions suggested that the proposed hydrogen transfer mechanism was thermodynamically feasible.These results provide theoretical foundation for further studying structural effects on the photochemical behaviors of proteins with triplet state BP and XT.

关 键 词：BENZOPHENONE XANTHONE TRYPTOPHAN TYROSINE laser flash photolysis 

分 类 号：O625.42[理学—有机化学] X52[理学—化学]