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Phenanthrene binding by humic acid-protein complexes as studied by passive dosing technique
Jian Zhao1, Zhenyu Wang, Saikat Ghosh
1Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
Environmental Pollution (Barking, Essex : 1987)
|September 20, 2013
Summary
Phenanthrene binding to humic substances and proteins was studied. Humic acid-bovine serum albumin complexes significantly enhanced phenanthrene binding, unlike other protein complexes.
Area of Science:
- Environmental Chemistry
- Biogeochemistry
- Organic Geochemistry
Background:
- Polycyclic aromatic hydrocarbons (PAHs) like phenanthrene are persistent organic pollutants.
- Humic substances (HS) and proteins are key environmental components influencing PAH fate.
- Understanding binding interactions is crucial for predicting PAH bioavailability and transport.
Purpose of the Study:
- To investigate phenanthrene binding to humic acids (HA) and proteins (bovine serum albumin (BSA), lysozyme, pepsin).
- To evaluate the binding behavior of phenanthrene with HA-protein complexes.
- To elucidate the mechanisms behind altered binding in complex matrices.
Main Methods:
- Passive dosing technique was employed to measure phenanthrene sorption.
- Sorption isotherms were analyzed using the Freundlich model.
- Binding affinities were compared across individual components and their complexes.
Main Results:
- Binding affinity order: HA-5 > HA-2 > BSA > pepsin > lysozyme.
- Phenanthrene binding to HA-BSA complexes was significantly enhanced compared to individual components.
- HA-lysozyme complexes showed reduced binding due to aggregation; HA-pepsin showed no enhancement.
Conclusions:
- Humic acid-protein complexation, particularly with BSA, can significantly increase phenanthrene binding.
- Protein unfolding, reduced aggregate size, and favorable complex conformations drive binding enhancement.
- The nature of the protein (charge, aggregation tendency) critically influences binding interactions.
Keywords:
Atomic force microscopyComplexationDissolved organic matterHydrophobic interactionHydrophobic organic contaminantsMore Related Videos
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