Fluhler E N, Hurley J K, Kochevar I E
Department of Dermatology, Massachusetts General Hospital, Boston 02114.
Biochim Biophys Acta. 1989 Mar 24;990(3):269-75. doi: 10.1016/s0304-4165(89)80044-3.
The intensity and wavelength-dependence of Rose-Bengal-mediated photoinhibition of red blood cell acetylcholinesterase has been studied. Irradiation of dye-membrane suspensions with 308 nm laser excitation resulted in enzyme inhibition almost 50% greater than that obtained with 514 nm laser excitation. Sodium azide and argon purging greatly decreased the photosensitized enzyme inhibition at both wavelengths. Although Rose Bengal photosensitized enzyme inhibition more efficiently upon excitation into Sn (308 nm) than into S1 (514 nm), Stern-Volmer analysis of sodium azide quenching data gave similar quenching efficiencies at both wavelengths. Irradiation of dye-membrane suspensions with increasing intensities (Nd:YAG, 532 nm, 40 ps pulse duration) resulted in a decrease in enzyme inhibition. Saturation of the Rose Bengal fluorescence intensity and light transmission occurred with nearly the same intensity-dependence, suggesting that ground-state depletion occurs at the higher intensities. Our results demonstrate that excitation of a sensitizer into higher-lying excited singlet states can result in enhanced sensitizing efficiency. However, attempts to populate such states in Rose Bengal by sequential two-photon absorption using high intensities resulted only in ground-state depletion.
研究了孟加拉玫瑰红介导的对红细胞乙酰胆碱酯酶光抑制作用的强度及波长依赖性。用308 nm激光激发照射染料 - 膜悬浮液所导致的酶抑制作用比用514 nm激光激发照射时几乎高50%。叠氮化钠和氩气吹扫在两个波长下都大大降低了光敏化酶抑制作用。尽管孟加拉玫瑰红在激发到Sn（308 nm）时比激发到S1（514 nm）时对酶的光敏化抑制作用更有效，但对叠氮化钠猝灭数据的斯特恩 - 沃尔默分析在两个波长下给出了相似的猝灭效率。用强度不断增加的光（Nd:YAG，532 nm，40 ps脉冲持续时间）照射染料 - 膜悬浮液导致酶抑制作用降低。孟加拉玫瑰红荧光强度和光透射率的饱和发生时具有几乎相同的强度依赖性，这表明在较高强度下发生基态耗尽。我们的结果表明，将敏化剂激发到较高的激发单重态可导致敏化效率提高。然而，试图通过使用高强度的顺序双光子吸收使孟加拉玫瑰红中的此类态布居，结果仅导致基态耗尽。
