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Qin X, Ding C, Tian Y, Dong J, Cheng B. Multifunctional Ti 3C 2T x MXene/Silver Nanowire Membranes with Excellent Catalytic, Antifouling, and Antibacterial Properties for Nitrophenol-Containing Water Purification. ACS Appl Mater Interfaces 2023; 15:48154-48167. [PMID: 37801365 DOI: 10.1021/acsami.3c09983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
The uncontrolled release of nitrophenol and dye pollutants into water systems is an increasingly serious worldwide concern, and thus efficient wastewater treatment technologies are urgently needed. Herein we report a novel two-dimensional (2D) transition metal carbides and/or nitrides (Ti3C2Tx MXene) membrane modified with silver nanowires (AgNWs) by vacuum assisted filtration technology for the ultrafast nitrophenol catalysis and water purification applications. Regular and controllable membrane transport channels were constructed by stacking Ti3C2Tx MXene nanosheets. Furthermore, the intercalation of AgNWs into the Ti3C2Tx MXene interlayer greatly enlarged the interlayer spacing, resulting in more gaps for fast and selective molecular transport. The optimized Ti3C2Tx MXene@AgNWs (M@A) membrane exhibited a water flux up to ∼191.9 L/(m2 h) while maintaining a high bovine serum albumin (BSA) rejection of ∼95.4%. We emphatically used M@A membranes as efficient catalysts for the reduction of 4-nitrophenol (4-NP), and the results indicated that M@A-12% membrane exhibited the greatest catalytic reduction ability, and recycling utilization. M@A-12% membrane also had an antibacterial rate of more than 99% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This work provides a possibility to expand the application of 2D multifunctional M@A membranes in wastewater treatment and pollutant catalytic degradation.
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Affiliation(s)
- Xiwen Qin
- State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes, Tianjin 300387, China
- School of Materials Science and Engineering, Tiangong University, Tianjin 300387, China
| | - Changkun Ding
- State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes, Tianjin 300387, China
- School of Materials Science and Engineering, Tiangong University, Tianjin 300387, China
| | - Yingying Tian
- State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes, Tianjin 300387, China
- School of Materials Science and Engineering, Tiangong University, Tianjin 300387, China
| | - Jiankang Dong
- State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes, Tianjin 300387, China
- School of Materials Science and Engineering, Tiangong University, Tianjin 300387, China
| | - Bowen Cheng
- State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes, Tianjin 300387, China
- School of Materials Science and Engineering, Tiangong University, Tianjin 300387, China
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Pimviriyakul P, Chaiyen P. Formation and stabilization of C4a-hydroperoxy-FAD by the Arg/Asn pair in HadA monooxygenase. FEBS J 2023; 290:176-195. [PMID: 35942637 DOI: 10.1111/febs.16591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/25/2022] [Accepted: 08/08/2022] [Indexed: 01/14/2023]
Abstract
HadA monooxygenase catalyses the detoxification of halogenated phenols and nitrophenols via dehalogenation and denitration respectively. C4a-hydroperoxy-FAD is a key reactive intermediate wherein its formation, protonation and stabilization reflect enzyme efficiency. Herein, transient kinetics, site-directed mutagenesis and pH-dependent behaviours of HadA reaction were employed to identify key features stabilizing C4a-adducts in HadA. The formation of C4a-hydroperoxy-FAD is pH independent, whereas its decay and protonation of distal oxygen are associated with pKa values of 8.5 and 8.4 respectively. These values are correlated with product formation within a pH range of 7.6-9.1, indicating the importance of adduct stabilization to enzymatic efficiency. We identified Arg101 as a key residue for reduced FAD (FADH- ) binding and C4a-hydroperoxy-FAD formation due to the loss of these abilities as well as enzyme activity in HadAR101A and HadAR101Q . Mutations of the neighbouring Asn447 do not affect the rate of C4a-hydroperoxy-FAD formation; however, they impair FADH- binding. The disruption of Arg101/Asn447 hydrogen bond networking in HadAN447A increases the pKa value of C4a-hydroperoxy-FAD decay to 9.5; however, this pKa was not altered in HadAN447D (pKa of 8.5). Thus, Arg101/Asn447 pair should provide important interactions for FADH- binding and maintain the pKa associated with H2 O2 elimination from C4a-hydroperoxy-FAD in HadA. In the presence of substrate, the formation of C4a-hydroxy-FAD at the hydroxylation step is pH insensitive, and it dehydrates to form the oxidized FAD with pKa of 7.9. This structural feature might help elucidate how the reactive intermediate was stabilized in other flavin-dependent monooxygenases.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
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Li G, Yuan B, Chen S, Gan L, Xu C. Covalent Organic Frameworks-TpPa-1 as an Emerging Platform for Electrochemical Sensing. Nanomaterials (Basel) 2022; 12:nano12172953. [PMID: 36079991 PMCID: PMC9457582 DOI: 10.3390/nano12172953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 06/07/2023]
Abstract
Covalent organic frameworks (COFs) are a new type of metal-free porous architecture with a well-designed pore structure and high stability. Here an efficient electrochemical sensing platform was demonstrated based on COFs TpPa-1 constructed by 1,3,5-triformylphloroglucinol (Tp) with p-phenylenediamine (Pa-1), which possesses abundant nitrogen and oxo-functionalities. COFs TpPa-1 exhibited good water dispersibility and strong adsorption affinities for Pd2+ and thus was used as loading support to modify Pd2+. The Pd2+-modified COFs TpPa-1 electrode (Pd2+/COFs) showed high electrocatalytic activity for both hydrazine oxidation reaction and nitrophenol reduction reaction. In addition, TpPa-1-derived nitrogen-doped carbon presented high activity for the electro-oxidation of reduced glutathione (GSH), and sensitive electrochemical detection of GSH was achieved. The presented COFs TpPa-1 can be utilized as a precursor as well as support for anchoring electro-active molecules and nanoparticles, which will be useful for electrochemical sensing and electrocatalysis.
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Chen Y, Fan S, Chen J, Deng L, Xiao Z. Catalytic Membrane Nanoreactor with Cu-Ag x Bimetallic Nanoparticles Immobilized in Membrane Pores for Enhanced Catalytic Performance. ACS Appl Mater Interfaces 2022; 14:9106-9115. [PMID: 35143180 DOI: 10.1021/acsami.1c22753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A catalytic membrane nanoreactor (CMNR) with Cu-Agx (where x is the millimolar concentration of AgNO3) bimetallic catalysts immobilized in membrane pores has been fabricated via coupling flowing synthesis and replacement reaction. Surface characterization by transmission electron microscopy (TEM) gives obvious evidence of the formation of Cu-Ag bimetallic core-shell nanostructures with Ag islands deposited on the Cu core metal. An apparent high shift phenomenon for the Cu element and a low shift phenomenon for the Ag element was determined by X-ray photoelectron spectroscopy (XPS), indicating a close interaction with the transfer of electron density from the Cu atom to the Ag atom. The hydrogenation catalysis of p-nitrophenol (p-NP) was tested to evaluate the catalytic performance. During the catalytic process, the Cu core acts as an electron-deficient site to adsorb and activate the -NO2 group for p-NP, and the Ag shell is beneficial for enhancing active H spilling to the Cu surface and then performing hydrogenation. A volcano-shaped apparent reaction rate constant can be achieved, which rises initially with the increasing Ag content and subsequently drops with a further increase in the Ag content. The highest value of 1071 min-1 can be achieved for CMNR immobilized with Cu-Ag2 owing to the suitable adsorption activation behavior and the best hydrogen spillover behavior.
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Affiliation(s)
- Yu Chen
- Sichuan University, No. 24 South Section 1, Yihuan Road, 610065 Chengdu, China
| | - Senqin Fan
- Sichuan University, No. 24 South Section 1, Yihuan Road, 610065 Chengdu, China
| | - Jiaojiao Chen
- Sichuan University, No. 24 South Section 1, Yihuan Road, 610065 Chengdu, China
| | - Lei Deng
- Sichuan University, No. 24 South Section 1, Yihuan Road, 610065 Chengdu, China
| | - Zeyi Xiao
- Sichuan University, No. 24 South Section 1, Yihuan Road, 610065 Chengdu, China
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Vibulcharoenkitja P, Suginta W, Schulte A. Electrochemical N-Acetyl-β-D-glucosaminidase Urinalysis: Toward Sensor Chip-Based Diagnostics of Kidney Malfunction. Biomolecules 2021; 11:biom11101433. [PMID: 34680066 PMCID: PMC8533638 DOI: 10.3390/biom11101433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022] Open
Abstract
N-Acetyl-β-D-glucosaminidase (GlcNAcase) is a valuable biomarker for kidney health, as an increased urinary level of the enzyme indicates cell damage within the renal tubular filtration system from acute or chronic organ injury or exposure to nephrotoxic compounds. Effective renal function is vital for physiological homeostasis, and early detection of acute or chronic renal malfunction is critically important for timely treatment decisions. Here, we introduce a novel option for electrochemical urinalysis of GlcNAcase, based on anodic differential pulse voltammetry at boron-doped diamond disk sensors of the oxidizable product 4-nitrophenol (4NP), which is released by the action of GlcNAcase on the synthetic substrate 4NP-N-acetyl-β-D-glucosaminide (GlcNAc-4NP), added to the test solution as a reporter molecule. The proposed voltammetric enzyme activity screen accurately distinguishes urine samples of normal, slightly elevated and critically high urinary GlcNAcase content without interference from other urinary constituents. Moreover, this practice has the potential to be adapted for use in a hand-held device for application in clinical laboratories by physicians or in personal home health care. Evidence is also presented for the effective management of the procedure with mass-producible screen-printed sensor chip platforms.
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Adeyeye Nafiu S, Shaheen Shah S, Aziz A, Shaikh MN. Biogenic Synthesis of Gold Nanoparticles on a Green Support as a Reusable Catalyst for the Hydrogenation of Nitroarene and Quinoline. Chem Asian J 2021; 16:1956-1966. [PMID: 34043274 DOI: 10.1002/asia.202100385] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/23/2021] [Indexed: 01/05/2023]
Abstract
Direct attachment of gold nanoparticles to a green support without the use of an external reducing agent and using it for removing toxic pollutants from wastewater, i. e., reduction of nitroarene to amine, are described. A novel approach involving the reduction of gold by the jute plant (Corchorus genus) stem-based (JPS) support itself to form nanoparticles (AuNPs) to be used as a catalytic system ('dip-catalyst') and its catalytic activity for the hydrogenation of series of nitroarenes in aqueous media are presented. AuNPs/JPS catalyst was characterized using SEM, UV-Vis, FTIR, TEM, XPS, and ICP-OES. Confined area elemental mapping exhibits uniform and homogeneous distribution of AuNPs on the support surface. TEM shows multi-faceted AuNPs in the range of 20-30 nm. The reactivity of AuNPs/JPS for the transfer hydrogenation of nitroarene as well as hydrogenation of quinoline under molecular H2 pressure was evaluated. Sodium borohydride, when used as the hydrogen source, demonstrates a high catalytic efficiency in the transfer hydrogenation reduction of 4-nitrophenol (4-NP). Quinoline is quantitatively and chemoselectively hydrogenated to 1,2,3,4-tetrahydroquinoline (py-THQ) using molecular hydrogen. Reusability studies show that AuNPs are stable on the support surface and their selectivity is not affected.
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Affiliation(s)
- Sodiq Adeyeye Nafiu
- Department of Chemistry, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia
| | - Syed Shaheen Shah
- Center of Research Excellence in Nanotechnology (CENT), King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia.,Physics Department, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Abdul Aziz
- Center of Research Excellence in Nanotechnology (CENT), King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia
| | - M Nasiruzzaman Shaikh
- Center of Research Excellence in Nanotechnology (CENT), King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia
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Pimviriyakul P, Jaruwat A, Chitnumsub P, Chaiyen P. Structural insights into a flavin-dependent dehalogenase HadA explain catalysis and substrate inhibition via quadruple π-stacking. J Biol Chem 2021; 297:100952. [PMID: 34252455 PMCID: PMC8342789 DOI: 10.1016/j.jbc.2021.100952] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 12/20/2022] Open
Abstract
HadA is a flavin-dependent monooxygenase catalyzing hydroxylation plus dehalogenation/denitration, which is useful for biodetoxification and biodetection. In this study, the X-ray structure of wild-type HadA (HadAWT) co-complexed with reduced FAD (FADH–) and 4-nitrophenol (4NP) (HadAWT−FADH–−4NP) was solved at 2.3-Å resolution, providing the first full package (with flavin and substrate bound) structure of a monooxygenase of this type. Residues Arg101, Gln158, Arg161, Thr193, Asp254, Arg233, and Arg439 constitute a flavin-binding pocket, whereas the 4NP-binding pocket contains the aromatic side chain of Phe206, which provides π-π stacking and also is a part of the hydrophobic pocket formed by Phe155, Phe286, Thr449, and Leu457. Based on site-directed mutagenesis and stopped-flow experiments, Thr193, Asp254, and His290 are important for C4a-hydroperoxyflavin formation with His290, also serving as a catalytic base for hydroxylation. We also identified a novel structural motif of quadruple π-stacking (π-π-π-π) provided by two 4NP and two Phe441 from two subunits. This motif promotes 4NP binding in a nonproductive dead-end complex, which prevents C4a-hydroperoxy-FAD formation when HadA is premixed with aromatic substrates. We also solved the structure of the HadAPhe441Val−FADH–−4NP complex at 2.3-Å resolution. Although 4NP can still bind to this variant, the quadruple π-stacking motif was disrupted. All HadAPhe441 variants lack substrate inhibition behavior, confirming that quadruple π-stacking is a main cause of dead-end complex formation. Moreover, the activities of these HadAPhe441 variants were improved by ⁓20%, suggesting that insights gained from the flavin-dependent monooxygenases illustrated here should be useful for future improvement of HadA’s biocatalytic applications.
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Affiliation(s)
- Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Aritsara Jaruwat
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, Pathumthani, Thailand.
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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Peng Z, Li Q, Zhang G, Zhao W, Lian H, Zhang S. [Solid phase extraction and high performance liquid chromatography with tetraaza[2]arene[2]triazine-bonded silica gel adsorbent for determination of nitrophenols and diethylstilbestrol in river water]. Se Pu 2020; 38:143-148. [PMID: 34213162 DOI: 10.3724/sp.j.1123.2019.06022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023] Open
Abstract
A novel method based on solid phase extraction (SPE)-high performance liquid chromatography (HPLC) was developed for the simultaneous determination of nitrophenols and diethylstilbestrol in river water. Tetraaza[2]arene[2]triazine-bonded silica gel, a homemade SPE adsorbent, was used to enrich the nitrophenols and diethylstilbestrol, and the optimal SPE and HPLC conditions were established. The sample solution was adjusted to pH 5, purified with a lab-made solid phase extraction column, and then eluted with 2 mL ammonia-methanol (2:98, v/v). The enriched sample was separated on a C8 column with methanol and 0.1% phosphoric acid solution as mobile phases in a gradient elution. Under the optimized conditions, the limits of detection (LOD, S/N=3) for the four target analytes were 0.03-0.3 μg/L, and the limits of quantification (LOQ, S/N=10) were 0.1-1.0 μg/L. The recoveries were 75.5%-104.2%, and the relative standard deviations (RSD, n=5) were less than 6.3%. The proposed method is accurate and reliable, and it has been successfully used for determining nitrophenols and diethylstilbestrol in river water.
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Affiliation(s)
- Zifang Peng
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Qin Li
- Food and Drug Inspection Institute of Zhengzhou, Zhengzhou 450008, China
- College of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Guangrui Zhang
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Wuduo Zhao
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
| | - Hongzhen Lian
- College of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Shusheng Zhang
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
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Larrea A, Eguizabal A, Sebastián V. Gas-Directed Production of Noble Metal-Magnetic Heteronanostructures in Continuous Fashion: Application in Catalysis. ACS Appl Mater Interfaces 2019; 11:43520-43532. [PMID: 31664814 DOI: 10.1021/acsami.9b15982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Complex nanomaterials produced by scale-up batch processes lack suitable control of shape, size distribution, chemical composition, and quality, because heat and mass transfer are seriously affected as the reactor volume increases. Here we use a novel continuous synthesis procedure, the active gas-liquid segmented flow, to produce noble metal-magnetic heteronanostructures with enormous interest in the fields of catalysis, biomedicine, environmental sensors, food monitoring, and chemical analysis. The microreactor technology proposed scales down the reaction volume to gain advantage of the large surface area to volume ratio with respect to conventional batch-type reactors, improving heat and mass transport and, consequently, promoting a uniform heating and mixing. The gas phase was introduced in the chemical reactor as gas slugs of nanoliter scale with a dual role: (1) passive mixing and (2) chemical directing agent to tune the crystallization of nanostructures in a continuous fashion. The shape, size, and magnetic properties of the resulting heteronanostructures, as well as the density, size, and composition of noble metal nanoparticles were tuned to show the versatility of the proposed approach in a timeline of 4 min. We demonstrated that the produced nanostructures provide excellent catalytic properties in the catalyzed hydrogenation of nitrophenols to aminophenols. Electron microscopy, UV-vis spectroscopy, and cyclic voltammetry studies showed the remarkable catalytic performance of the produced heteronanostructures.
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Affiliation(s)
- Ane Larrea
- Institute of Nanoscience of Aragon and Department of Chemical Engineering , University of Zaragoza , E-50018 Zaragoza , Spain
| | - Adela Eguizabal
- Institute of Nanoscience of Aragon and Department of Chemical Engineering , University of Zaragoza , E-50018 Zaragoza , Spain
| | - Víctor Sebastián
- Institute of Nanoscience of Aragon and Department of Chemical Engineering , University of Zaragoza , E-50018 Zaragoza , Spain
- Networking Research Center in Bioengineering, Biomaterials and Nanomedicine , E-50018 Zaragoza , Spain
- Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza , Pedro Cerbuna 12 , 50009 Zaragoza , Spain
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Pimviriyakul P, Chaiyen P. A complete bioconversion cascade for dehalogenation and denitration by bacterial flavin-dependent enzymes. J Biol Chem 2018; 293:18525-18539. [PMID: 30282807 DOI: 10.1074/jbc.ra118.005538] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/29/2018] [Indexed: 12/17/2022] Open
Abstract
Halogenated phenol and nitrophenols are toxic compounds that are widely accumulated in the environment. Enzymes in the had operon from the bacterium Ralstonia pickettii DTP0602 have the potential for application as biocatalysts in the degradation of many of these toxic chemicals. HadA monooxygenase previously was identified as a two-component reduced FAD (FADH-)-utilizing monooxygenase with dual activities of dehalogenation and denitration. However, the partner enzymes of HadA, that is, the flavin reductase and quinone reductase that provide the FADH- for HadA and reduce quinone to hydroquinone, remain to be identified. In this report, we overexpressed and purified the flavin reductases, HadB and HadX, to investigate their functional and catalytic properties. Our results indicated that HadB is an FMN-dependent quinone reductase that converts the quinone products from HadA to hydroquinone compounds that are more stable and can be assimilated by downstream enzymes in the pathway. Transient kinetics indicated that HadB prefers NADH and menadione as the electron donor and acceptor, respectively. We found that HadX is an FAD-bound flavin reductase, which can generate FADH- for HadA to catalyze dehalogenation or denitration reactions. Thermodynamic and transient kinetic experiments revealed that HadX prefers to bind FAD over FADH- and that HadX can transfer FADH- from HadX to HadA via free diffusion. Moreover, HadX rapidly catalyzed NADH-mediated reduction of flavin and provided the FADH- for a monooxygenase of a different system. Combination of all three flavin-dependent enzymes, i.e. HadA/HadB/HadX, reconstituted an effective dehalogenation and denitration cascade, which may be useful for future bioremediation applications.
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Affiliation(s)
- Panu Pimviriyakul
- From the School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210 and.,the Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 14000, Thailand
| | - Pimchai Chaiyen
- From the School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210 and
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Neng NR, Nogueira JMF. Determination of phenol compounds in surface water matrices by bar adsorptive microextraction-high performance liquid chromatography-diode array detection. Molecules 2014; 19:9369-79. [PMID: 24995922 PMCID: PMC6271164 DOI: 10.3390/molecules19079369] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 11/29/2022] Open
Abstract
Bar adsorptive microextraction combined with liquid desorption followed by high performance liquid chromatography with diode array detection (BAµE-LD/HPLC-DAD) is proposed for the determination of trace levels of five phenol compounds (3-nitrophenol, 4-nitrophenol, bisphenol-A, 4-n-octylphenol and 4-n-nonylphenol) in surface water matrices. By using a polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phase, high selectivity and efficiency is achieved even against polydimethylsiloxane through stir bar sorptive extraction. Assays performed by BAµE(PS-DVB)-LD/HPLC-DAD on 25 mL water samples spiked at the 10.0 µg/L levels yielded recoveries over 88.0%±5.7% for all five analytes, under optimized experimental conditions. The analytical performance showed good precision (RSD<15%), detection limits of 0.25 µg/L and linear dynamic ranges (1.0-25.0 μg/L) with determination coefficient higher than 0.9904. By using the standard addition method, the application of the present method to surface water matrices allowed very good performances at the trace level. The proposed methodology proved to be a suitable alternative to monitor phenol compounds in surface water matrices, showing to be easy to implement, reliable, sensitive and requiring a low sample volume.
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Affiliation(s)
- Nuno R Neng
- University of Lisbon, Faculty of Sciences, Chemistry and Biochemistry Department and Center of Chemistry and Biochemistry, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal.
| | - José M F Nogueira
- University of Lisbon, Faculty of Sciences, Chemistry and Biochemistry Department and Center of Chemistry and Biochemistry, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal.
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