Shenzhen Key Laboratory of Environmental Chemistry and Ecological Remediation, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China.
Centre for Translational Medicine Research & Development, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518060, China.
Int J Biol Macromol. 2022 Aug 31;215:606-614. doi: 10.1016/j.ijbiomac.2022.06.124. Epub 2022 Jun 21.
A mediation strategy can effectively overcome the low reaction activity of enzymes with nonspecific substrates. In this study, we demonstrated how phenol compounds can mitigate the substrate limitation of HRP in catalytic degradation of various organic pollutants. In a classical HRP/HO system, phenol and natural phenolic compounds (4-HBA & pHBA), exhibited up to over 100-fold enhancement in eliminating organic dyes and persistent antibiotics while the loading is only 2-5 wt%. A combination of molecular modelling, docking and frontier orbital energy analysis was employed to elucidate the catalytic performance and mechanism. We revealed that (1) generating phenoxyl radicals required the proximity of mediators to the HRP active centre, and (2) the subsequent efficient radical transfer to pollutants was determined by the large energy gap between the SOMO energy of phenoxyl radicals and the HOMO energy of phenols. When considering phenols as pollutants, we showed a synergistic effect on catalytic degradation of phenols, dyes, and tetracycline with a removal efficiency of 71-92 %. Overall, this work not only demonstrates that phenoxyl mediators can overcome the lower efficiency and substrate-specificity limitations of the HRP/HO system but also revealed their structure-mediation relationship, implying great potential in the biodegradation of diverse pollutants and their mixtures.
一种介体策略可以有效地克服非特异性底物酶的低反应活性。在这项研究中，我们展示了酚类化合物如何减轻 HRP 在催化降解各种有机污染物中的底物限制。在经典的 HRP/HO 体系中，酚类和天然酚类化合物（4-HBA 和 pHBA）在去除有机染料和持久性抗生素方面表现出高达 100 倍以上的增强，而负载量仅为 2-5wt%。我们采用分子建模、对接和前沿轨道能量分析相结合的方法来阐明催化性能和机制。我们揭示了（1）生成苯氧自由基需要介体与 HRP 活性中心的接近，以及（2）随后的自由基向污染物的有效转移取决于苯氧自由基的 SOMO 能量和酚类 HOMO 能量之间的大能量间隙。当考虑酚类作为污染物时，我们展示了对酚类、染料和四环素的协同催化降解作用，去除效率为 71-92%。总的来说，这项工作不仅证明了苯氧介体可以克服 HRP/HO 体系效率较低和底物特异性限制，还揭示了它们的结构-介体关系，这意味着它们在多种污染物及其混合物的生物降解方面具有巨大的潜力。
