Laccases are a type of extracellular enzyme produced by fungi, bacteria, and plants. Laccase can catalyze one-electron oxidation of a variety of phenolic compounds using molecular oxygen as the electron acceptor. In this study, transformation of halophenols (XPs) in laccase-catalyzed oxidation processes was explored. We first examined the intrinsic reaction kinetics and found that the transformation of XPs appeared first order to the concentrations of both XPs and laccase. A numerical model was developed to describe the role of humic acid (HA) in this process. It was demonstrated that HA could reverse the oxidation of XPs by acting as the inner filtrator of XP radical intermediates formed upon reactions between the substrates and laccase. The extent of such reversion was proportional to HA concentration. MS analysis in combination with quantum chemistry computation suggested that coupling products were generated. XPs coupled to each via C—C or C—O—C pathways, generating hydroxyl polyhalogenated biphenyl ethers (OH-PCDEs) and hydroxyl polyhalogenated biphenyls, respectively. Many of these polyhalogenated products are known to be hazardous to the ecosystem and human health, but they are not synthetic chemicals. This study shed light on their genesis in the environmental media.
Wenhui Liang,Yanting Chen,Muwei Huang,Zeyu Song,Cancan Li,Yanhong Zheng,Zhongsheng Yi
Graphical This manuscript employs computational simulations and multispectral analysis to elucidate the binding sites and underlying mechanisms of the interaction between halogenated phenols (HPS) and transthyretin (TTR), thereby enhancing the comprehension of their molecular dynamics and the consequent toxicological implications of HPS exposure. Moreover, it contributes significantly to the identification of potential environmental endocrine-disrupting compounds. The aim of this study was to understand the interaction between transthyretin (TTR) and halogenated phenols (HPs) including 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), pentachlorophenol (PCP), 2-bromophenol (2-BP), 2,4-dibromophenol (DBP) and 2,4,6-tribromophenol (TBP). Computer simulation and multi-spectroscopy techniques were used to investigate the interaction. The fluorescence of TTR was found to be quenched through static quenching and non-radiative energy transfer by HPs, suggesting that the binding process between HPs and TTR was primarily influenced by van der Waals forces and hydrogen bonds. ANS substitution experiments indicated that HPs interacted with TTR at the T4 binding site. Three-dimensional fluorescence spectra and Fourier transform infrared spectroscopy were used to investigate the conformational and microenvironmental changes of TTR resulting from the interactions with HPs. Additionally, molecular docking and reduced density gradient analysis were used to identify the specific residues and binding forces involved in the interaction between HPs and TTR binding sites. The findings were subsequently validated through quantum chemical analysis. This research integrates state-of-the-art multispectral analytical methodologies with sophisticated computational modeling to introduce an innovative approach for dissecting the interactions between halogenated phenols (HPs) and transthyretin (TTR). This methodology offers a novel avenue for investigating the molecular interplay between HPs and TTR, thereby providing critical insights that are instrumental in assessing the latent toxicity of these compounds.
Zifan Hu,Weiyang Sun,Jiaqi Guo,Xuan Wang,Li Yong,Lin Ren,Dejian Feng,Xiaoli Zou
Using high-performance liquid chromatography-mass spectrometry, fifteen bisphenols and halogenated phenols were simultaneously analyzed in tea for the first time in China. Response surface methodology was used to optimize sample preparation conditions based on QuEChERS. Finally, the limits of detection and the limits of quantification were 0.0200–0.173 μg/kg and 0.0892–0.770 μg/kg, respectively. The recoveries were 70 %–120 % for most compounds (except for some compounds at low spiked concentrations) with RSDs <20 %. Then 135 dried tea samples were analyzed. Bisphenol S, A and F were the predominant bisphenol contaminants with detection rates above 80 %, and the median level of bisphenol F (4.90 μg/kg) was even higher than that of bisphenol A (2.74 μg/kg). Bisphenol A ( p < 0.001) and bisphenol F ( p = 0.007) were significantly higher in black tea than in green tea. Hazard index was estimated and bisphenols in tea may pose potential risks to human health.
危险品化学品经营许可证（带存储）