Zhu Hongping, Wang Wenfeng, Yao Side
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Invest New Drugs. 2006 Nov;24(6):465-70. doi: 10.1007/s10637-006-7073-4.
Excitation of the thioxanthone derivatives (TXs), 2, 4-diethylthioxanthone (DETX) and 2-(2,3-epoxypropyloxy) thioxanthone (ETX) in acetonitrile/water mixture solution (1:1, v/v) upon 355 nm laser flash produced the triplet of TXs ((3)TXs()). Characteristic absorption spectra of (3)TXs()(590 nm) were recorded and rate constants of (3)TXs() quenched by O(2) and by its ground state were determined (9.8 x 10(9) M(-1) s(-1), 7.3 x 10(9) M(-1) s(-1) and 2.6 x 10(8) M(-1) s(-1), 2.2 x 10(8) M(-1) s(-1) respectively). The reactions of some amino acids oxidized by (3)TXs() were carried out. It has been found that tryptophan (Trp) and tyrosine (Tyr) can quench (3)TXs() via electron transfer process and related quenching rate constants were obtained. (3)TXs() induced protein damage was investigated using electrophoresis and significant levels of dimerisation were observed under aerobic and anaerobic conditions. The influence of photo-sensitizer's structure on photo-oxidation of amino acid and protein has been discussed.
在乙腈/水混合溶液（1:1，v/v）中，用355nm激光闪光激发噻吨酮衍生物（TXs）、2,4 - 二乙基噻吨酮（DETX）和2 - (2,3 - 环氧丙氧基)噻吨酮（ETX），产生了TXs的三重态（(3)TXs()）。记录了(3)TXs()（590nm）的特征吸收光谱，并测定了(3)TXs()被O₂及其基态猝灭的速率常数（分别为9.8×10⁹ M⁻¹ s⁻¹、7.3×10⁹ M⁻¹ s⁻¹和2.6×10⁸ M⁻¹ s⁻¹、2.2×10⁸ M⁻¹ s⁻¹）。进行了一些被(3)TXs()氧化的氨基酸的反应。已发现色氨酸（Trp）和酪氨酸（Tyr）可通过电子转移过程猝灭(3)TXs()，并获得了相关的猝灭速率常数。使用电泳研究了(3)TXs()诱导的蛋白质损伤，在有氧和无氧条件下均观察到显著水平的二聚化。讨论了光敏剂结构对氨基酸和蛋白质光氧化的影响。
