Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein
Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein
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DOI：
10.1016/s0301-0104(02)00969-2
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发表时间：
2003-01-15
期刊：
影响因子：
2.3
通讯作者：
Hegemann, P
中科院分区：
文献类型：
--
作者：
Drössler, P;Holzer, W;Hegemann, P
测定了核黄素在甲醇、DMSO、水以及含有硫原子的氨基酸蛋氨酸和半胱氨酸的水溶液中的荧光量子分布、荧光量子产率和荧光寿命。在甲醇、DMSO 和水 (pH = 4-8) 中，仅观察到由于系间交叉和内部转换导致的动态荧光减弱。在 pH = 5.25-9 的蛋氨酸水溶液中，可能由于核黄素阴离子-蛋氨酸阳离子对的形成而发生与 pH 无关的静态和动态荧光猝灭。在半胱氨酸水溶液（pH 范围为 4.15 至 9）中，由于半胱氨酸硫醇盐的形成，荧光猝灭随着 pH 值的升高而增加。低pH值下存在的半胱氨酸硫醇形式不与中性核黄素反应。高pH值下存在的半胱氨酸硫醇盐似乎与中性核黄素反应，通过半胱氨酸硫醇盐还原成半胱氨酸硫醇形式，导致核黄素去质子化（阴离子形成）。 (C) 2002 Elsevier Science B.V. 保留所有权利。
The fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes of riboflavin in methanol, DMSO, water, and aqueous solutions of the sulphur atom containing amino acids methionin and cystein have been determined. In methanol, DMSO, and water (pH = 4-8) only dynamic fluorescence reduction due to intersystem crossing and internal conversion is observed. In aqueous methionin solutions of pH = 5.25-9 a pH independent static and dynamic fluorescence quenching occurs probably due to riboflavin anion-methionin cation pair formation. In aqueous cystein solutions (pH range from 4.15 to 9) the fluorescence quenching increases with rising pH due to cystein thiolate formation. The cystein thiol form present at low pH does not react with neutral riboflavin. Cystein thiolate present at high pH seems to react with neutral riboflavin causing riboflavin deprotonation (anion formation) by cystein thiolate reduction to the cystein thiol form. (C) 2002 Elsevier Science B.V. All rights reserved.