Interactions between protein-like and humic-like components in dissolved organic matter revealed by fluorescence quenching.
Interactions between protein-like and humic-like components in dissolved organic matter revealed by fluorescence quenching.
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DOI：
10.1016/j.watres.2014.10.024
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发表时间：
2015
期刊：
影响因子：
12.8
通讯作者：
Zhigang Wang;Jing Cao;F. Meng
中科院分区：
文献类型：
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作者：
Zhigang Wang;Jing Cao;F. Meng
许多报告通过表征 FDOM 成分的荧光猝灭，记录了荧光溶解有机物 (FDOM) 与其他化合物（例如金属和痕量污染物）的相互作用。由于 FDOM 由众多组件组成，因此可能会发生组件间交互。本研究通过滴定实验和端元混合测试研究了 FDOM 中类蛋白质和类腐殖质成分之间的相互作用。我们发现 FDOM 样品中类蛋白质和类腐殖酸成分的共现导致其与成分间相互作用相关的荧光峰之间的重叠行为。我们的结果表明，FDOM 样品中的类腐殖质成分可以极大地猝灭类蛋白质成分的荧光，例如，在滴定实验中，来自 Suwannee River 和 Nordic Reservoir FDOM 的类腐殖质成分对酪氨酸（分别为 52% 和 46%）和色氨酸（分别为 35% 和 36%）产生了显着的猝灭效果。然而，类腐殖酸成分的荧光不受类蛋白质成分的影响。在络合模型的帮助下，我们发现类蛋白质和类腐殖质成分之间的结合能力取决于它们的来源。这项研究可以增强我们目前对 FDOM 在水中作用的认识，对于荧光光谱法监测 FDOM 也很重要。
Numerous reports have documented the interactions of fluorescent dissolved organic matter (FDOM) with other compounds such as metals and trace contaminants by characterizing the fluorescence quenching of the FDOM components. As FDOM is composed of numerous components, inter-component interactions can potentially take place. This study investigated the interactions between protein-like and humic-like components in FDOM using titration experiments and end-member mixing tests. We found that the co-occurrence of protein-like and humic-like components in FDOM samples resulted in an overlap behavior between their fluorescence peaks related to inter-component interactions. Our results suggest that the fluorescence of the protein-like components could be greatly quenched by the humic-like components in the FDOM samples, e.g., the humic-like components from Suwannee River and Nordic Reservoir FDOM yielded significant quenching effect for tyrosine (52% and 46%, respectively) and tryptophan (35% and 36%, respectively) in the titration experiments. The fluorescence of the humic-like components, however, was not impacted by the protein-like components. With the help of complexation modeling, we found that the binding capability between protein-like and humic-like components was dependent on their sources. This study could enhance our current knowledge on the role of FDOM in water and it is also important to the monitoring of FDOM by fluorescence spectroscopy.