1
|
Xu C, Lin P, Garimella R, Li D, Xing W, Patterson NE, Kaplan DI, Yeager CM, Hatcher PG, Santschi PH. 1H- 13C heteronuclear single quantum coherence NMR evidence for iodination of natural organic matter influencing organo-iodine mobility in the environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:152546. [PMID: 34973322 DOI: 10.1016/j.scitotenv.2021.152546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
The complex biogeochemical behavior of iodine (I) isotopes and their interaction with natural organic matter (NOM) pose a challenge for transport models. Here, we present results from iodination experiments with humic acid (HA) and fulvic acid (FA) using 1H-13C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy. Even though not a quantitative approach, 1H-13C HSQC NMR corroborated that iodination of NOM occurs primarily through aromatic electrophilic substitution of proton by I, and also revealed how iodination chemically alters HA and FA in a manner that potentially affects the mobility of iodinated NOM in the environment. Three types of iodination experiments were conducted with HA and FA: a) non-enzymatic iodination by IO3- (pH 3) and I- (pH 4 and 7), b) addition of lactoperoxidase to promote I--iodination in the presence of the co-substrate, H2O2 (pH 7), and c) addition of laccase for facilitating I--iodination in the presence of O2, with or without a mediator (pH 4). When mediators or H2O2 were present, extracellular oxidases and peroxidases enhanced I- incorporation into NOM by between 54% and 3400%. Iodination of HA, which was less than that of FA, enhanced HA's stability (inferred from increases in aliphatic compounds, decreases in carbohydrate moieties, and thus increased molecular hydrophobicity) yet reduced HA's tendency to incorporate more iodine. As such, HA is expected to act more as a sink for iodine in the environment. In contrast, iodination of FA appeared to generate additional iodine binding sites, which resulted in greater iodine uptake capability and enhanced mobility (inferred from decreases in aliphatic compounds, increases in carbohydrates, and thus decreases in molecular hydrophobicity). These results indicate that certain NOM moieties may enhance while others may inhibit radioiodine mobility in the aqueous environment.
Collapse
Affiliation(s)
- Chen Xu
- Department of Marine Science, Texas A & M University at Galveston, Galveston, TX 77551, United States.
| | - Peng Lin
- Department of Marine Science, Texas A & M University at Galveston, Galveston, TX 77551, United States
| | | | - Dien Li
- Savannah River National Laboratory, Aiken, SC 29808, United States
| | - Wei Xing
- Department of Marine Science, Texas A & M University at Galveston, Galveston, TX 77551, United States
| | - Nicole E Patterson
- Department of Marine Science, Texas A & M University at Galveston, Galveston, TX 77551, United States
| | - Daniel I Kaplan
- Savannah River National Laboratory, Aiken, SC 29808, United States
| | - Chris M Yeager
- Los Alamos National Laboratory, Los Alamos, NM 87545, United States
| | - Patrick G Hatcher
- Department of Chemistry, Old Dominion University, Norfolk, VA 23529, United States
| | - Peter H Santschi
- Department of Marine Science, Texas A & M University at Galveston, Galveston, TX 77551, United States
| |
Collapse
|
2
|
Coria-Oriundo LL, Battaglini F, Wirth SA. Efficient decolorization of recalcitrant dyes at neutral/alkaline pH by a new bacterial laccase-mediator system. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 217:112237. [PMID: 33892342 DOI: 10.1016/j.ecoenv.2021.112237] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 03/31/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Laccases and laccase-mediator systems (LMS) are versatile catalysts that can oxidize a broad range of substrates coupled to the sole reduction of dioxygen to water. They possess many biotechnological applications in paper, textile, and food industries, bioethanol production, organic synthesis, detection and degradation of pollutants, and biofuel cell development. In particular, bacterial laccases are getting relevance due to their activity in a wide range of pH and temperature and their robustness under harsh conditions. However, the enzyme and the redox mediator's availability and costs limit their large-scale commercial use. Here we demonstrate that β-(10-phenothiazyl)-propionic acid can be used as an efficient and low-cost redox mediator for decolorizing synthetic dyes by the recombinant laccase SilA from Streptomyces ipomoeae produced in E. coli. This new LMS can decolorize more than 80% indigo carmine and malachite green in 1 h at pH = 8.0 and 2 h in tap water (pH = 6.8). Furthermore, it decolorized more than 40% of anthraquinone dye remazol brilliant blue R and 80% of azo dye xylidine ponceau in 5 h at 50 °C, pH 8.0. It supported at least 3 decolorization cycles without losing activity, representing an attractive candidate for a cost-effective and environmentally friendly LMS functional at neutral to alkaline pH.
Collapse
Affiliation(s)
- Lucy L Coria-Oriundo
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía, INQUIMAE, DQIAQF, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina; Facultad de Ciencias, Universidad Nacional de Ingeniería, Av. Tupac Amaru 210, Lima 25, Perú
| | - Fernando Battaglini
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía, INQUIMAE, DQIAQF, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina
| | - Sonia A Wirth
- Laboratorio de Agrobiotecnología, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Argentina; Instituto de Biodiversidad y Biología Experimental y Aplicada, IBBEA-CONICET-UBA, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Argentina.
| |
Collapse
|
3
|
Jeong D, Choi KY. Biodegradation of Tetracycline Antibiotic by Laccase Biocatalyst Immobilized on Chitosan-Tripolyphosphate Beads. APPL BIOCHEM MICRO+ 2020. [DOI: 10.1134/s0003683820030047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
4
|
Laurynėnas A, Butkevičius M, Dagys M, Shleev S, Kulys J. Consecutive Marcus Electron and Proton Transfer in Heme Peroxidase Compound II-Catalysed Oxidation Revealed by Arrhenius Plots. Sci Rep 2019; 9:14092. [PMID: 31575893 PMCID: PMC6773748 DOI: 10.1038/s41598-019-50466-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/12/2019] [Indexed: 11/16/2022] Open
Abstract
Electron and proton transfer reactions in enzymes are enigmatic and have attracted a great deal of theoretical, experimental, and practical attention. The oxidoreductases provide model systems for testing theoretical predictions, applying experimental techniques to gain insight into catalytic mechanisms, and creating industrially important bio(electro)conversion processes. Most previous and ongoing research on enzymatic electron transfer has exploited a theoretically and practically sound but limited approach that uses a series of structurally similar ("homologous") substrates, measures reaction rate constants and Gibbs free energies of reactions, and analyses trends predicted by electron transfer theory. This approach, proposed half a century ago, is based on a hitherto unproved hypothesis that pre-exponential factors of rate constants are similar for homologous substrates. Here, we propose a novel approach to investigating electron and proton transfer catalysed by oxidoreductases. We demonstrate the validity of this new approach for elucidating the kinetics of oxidation of "non-homologous" substrates catalysed by compound II of Coprinopsis cinerea and Armoracia rusticana peroxidases. This study - using the Marcus theory - demonstrates that reactions are not only limited by electron transfer, but a proton is transferred after the electron transfer event and thus both events control the reaction rate of peroxidase-catalysed oxidation of substrates.
Collapse
Affiliation(s)
- Audrius Laurynėnas
- Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257, Vilnius, Lithuania.
| | - Marius Butkevičius
- Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257, Vilnius, Lithuania
| | - Marius Dagys
- Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257, Vilnius, Lithuania
| | - Sergey Shleev
- Malmö University, Jan Waldenströmsgata 25, SE-214 28, Malmö, Sweden
| | - Juozas Kulys
- Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257, Vilnius, Lithuania
| |
Collapse
|
5
|
Machovina MM, Ellis ES, Carney TJ, Brushett FR, DuBois JL. How a cofactor-free protein environment lowers the barrier to O 2 reactivity. J Biol Chem 2019; 294:3661-3669. [PMID: 30602564 DOI: 10.1074/jbc.ra118.006144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/01/2019] [Indexed: 11/06/2022] Open
Abstract
Molecular oxygen (O2)-utilizing enzymes are among the most important in biology. The abundance of O2, its thermodynamic power, and the benign nature of its end products have raised interest in oxidases and oxygenases for biotechnological applications. Although most O2-dependent enzymes have an absolute requirement for an O2-activating cofactor, several classes of oxidases and oxygenases accelerate direct reactions between substrate and O2 using only the protein environment. Nogalamycin monooxygenase (NMO) from Streptomyces nogalater is a cofactor-independent enzyme that catalyzes rate-limiting electron transfer between its substrate and O2 Here, using enzyme-kinetic, cyclic voltammetry, and mutagenesis methods, we demonstrate that NMO initially activates the substrate, lowering its pKa by 1.0 unit (ΔG* = 1.4 kcal mol-1). We found that the one-electron reduction potential, measured for the deprotonated substrate both inside and outside the protein environment, increases by 85 mV inside NMO, corresponding to a ΔΔG 0' of 2.0 kcal mol-1 (0.087 eV) and that the activation barrier, ΔG ‡, is lowered by 4.8 kcal mol-1 (0.21 eV). Applying the Marcus model, we observed that this suggests a sizable decrease of 28 kcal mol-1 (1.4 eV) in the reorganization energy (λ), which constitutes the major portion of the protein environment's effect in lowering the reaction barrier. A similar role for the protein has been proposed in several cofactor-dependent systems and may reflect a broader trend in O2-utilizing proteins. In summary, NMO's protein environment facilitates direct electron transfer, and NMO accelerates rate-limiting electron transfer by strongly lowering the reorganization energy.
Collapse
Affiliation(s)
- Melodie M Machovina
- From the Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715-3400 and
| | - Emerald S Ellis
- From the Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715-3400 and
| | | | - Fikile R Brushett
- Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307
| | - Jennifer L DuBois
- From the Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715-3400 and
| |
Collapse
|
6
|
Vazquez-Duhalt R, Aguila SA, Arrocha AA, Ayala M. QM/MM Molecular Modeling and Marcus Theory in the Molecular Design of Electrodes for Enzymatic Fuel Cells. ChemElectroChem 2013. [DOI: 10.1002/celc.201300096] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
7
|
Nicolini C, Bruzzese D, Cambria MT, Bragazzi NL, Pechkova E. Recombinant Laccase: I. Enzyme cloning and characterization. J Cell Biochem 2013; 114:599-605. [DOI: 10.1002/jcb.24397] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 09/07/2012] [Indexed: 11/08/2022]
|
8
|
|
9
|
Probing Reactivity of PQQ-Dependent Carbohydrate Dehydrogenases Using Artificial Electron Acceptor. Appl Biochem Biotechnol 2010; 163:404-14. [DOI: 10.1007/s12010-010-9048-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 07/19/2010] [Indexed: 10/19/2022]
|
10
|
Kulys J, Tetianec L, Bratkovskaja I. Pyrroloquinoline quinone-dependent carbohydrate dehydrogenase: Activity enhancement and the role of artificial electron acceptors. Biotechnol J 2010; 5:822-8. [DOI: 10.1002/biot.201000119] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
11
|
|
12
|
Kinetics of N-substituted phenothiazines and N-substituted phenoxazines oxidation catalyzed by fungal laccases. Open Life Sci 2009. [DOI: 10.2478/s11535-008-0050-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractLaccase-catalyzed oxidation of N-substituted phenothiazines and N-substituted phenoxazines was investigated at pH 5.5 and 25°C. The recombinant laccase from Polyporus pinsitus (rPpL) and the laccase from Myceliophthora thermophila (rMtL) were used. The dependence of initial reaction rate on substrate concentration was analyzed by applying the laccase action scheme in which the laccase native intermediate (NI) reacts with a substrate forming reduced enzyme. The reduced laccase produces peroxide intermediate (PI) which in turn decays to the NI. The calculated constant (kox) values of the PI formation are (6.1±3.1)×105 M−1s−1 for rPpL and (2.5±0.9)×104 M−1s−1 for rMtL. The bimolecular constants of the reaction of the native intermediate with electron donor (kred) vary in the interval from 2.2×105 to 2.1×107 M−1s−1 for rPpL and from 1.3×102 to 1.8×105 M-1s−1 for rMtL. The larger reactivity of rPpL in comparison to rMtL is associated with the higher redox potential of type I Cu of rPpL. The variation of kred values for both laccases correlates with the change of the redox potential of substrates. Following outer sphere (Marcus) electron transfer mechanism the calculated activationless electron transfer rate and the apparent reorganization energy are 5.0×107 M−1s−1 and 0.29 eV, respectively.
Collapse
|
13
|
Evtyugin GA, Budnikov GK, Porfir’eva AV. Electrochemical DNA-sensors for determining biologically active low-molecular compounds. RUSS J GEN CHEM+ 2009. [DOI: 10.1134/s107036320812030x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
14
|
Kinetic study of peroxidase-catalyzed oxidation of 1-hydroxypyrene. Development of a nanomolar hydrogen peroxide detection system. Open Life Sci 2008. [DOI: 10.2478/s11535-008-0021-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractKinetics of 1-hydroxypyrene (1-HP) oxidation catalyzed with recombinant Coprinus cinereus (rCiP) and horseradish (HRP) peroxidases was investigated with a special emphasis for developing a nanomolar hydrogen peroxide (H2O2) detection system. At pH 8.0 the bimolecular constants of 1-HP oxidation with the ferryl compounds of rCiP and HRP were equal to (1.0 ± 0.3) × 108 M−1 s−1 and (0.6 ± 0.2) × 108 M−1 s−1, respectively. High bimolecular constants and fluorescence quantum yield of 1-HP (0.66) permitted detection as low as 21 nM of H2O2. To optimize the detection system 1-HP oxidation was modeled at steady-state conditions in the range pH 5.0 to pH 8.0. The 1-HP based detection system was compared with the Amplex Red system. The peroxidase-catalyzed 1-HP oxidation system was used for determination of ozone in the air.
Collapse
|
15
|
Boussaad S, Diner BA, Fan J. Influence of Redox Molecules on the Electronic Conductance of Single-Walled Carbon Nanotube Field-Effect Transistors: Application to Chemical and Biological Sensing. J Am Chem Soc 2008; 130:3780-7. [DOI: 10.1021/ja075131f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Salah Boussaad
- Central Research and Development, Experimental Station, E. I. du Pont de Nemours & Co, Wilmington, Delaware 19880-0173
| | - Bruce A. Diner
- Central Research and Development, Experimental Station, E. I. du Pont de Nemours & Co, Wilmington, Delaware 19880-0173
| | - Janine Fan
- Central Research and Development, Experimental Station, E. I. du Pont de Nemours & Co, Wilmington, Delaware 19880-0173
| |
Collapse
|
16
|
Tadesse MA, D'Annibale A, Galli C, Gentili P, Sergi F. An assessment of the relative contributions of redox and steric issues to laccase specificity towards putative substrates. Org Biomol Chem 2008; 6:868-78. [DOI: 10.1039/b716002j] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
17
|
Kulys J, Vidziunaite R, Janciene R, Palaima A. Spectroelectrochemical Study ofN-Substituted Phenoxazines as Electrochemical Labels of Biomolecules. ELECTROANAL 2006. [DOI: 10.1002/elan.200603604] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
18
|
|
19
|
Kulys J, Tetianec L. Synergistic substrates determination with biosensors. Biosens Bioelectron 2005; 21:152-8. [PMID: 15967363 DOI: 10.1016/j.bios.2004.08.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Revised: 08/10/2004] [Accepted: 08/11/2004] [Indexed: 10/26/2022]
Abstract
High sensitive biosensors for heterocyclic compounds determination were built using oxidases-catalyzed hexacyanoferrate(III) reduction in the presence of these compounds. As oxidases Aspergillus niger glucose oxidase and recombinant Microdochium nivale carbohydrate oxidase were used. The biosensors were build using graphite electrodes and entrapped solution of the oxidases. The sensitivity of the biosensors achieves 5.2-14.5 microA microM-1 cm-2. The detection limit of some heterocyclic compounds was 0.2 microM. The sensitivity of biosensors was 300-10,000 times larger in comparison to hexacyanoferrate(III). To background the scheme of biosensors action kinetics of synergistic substrates oxidation was investigated in homogenous solution. The measurements showed that the rate of the reduction of low reactive substrate (hexacyanoferrate(III)) increased due to synergistic action of high reactive substrates (oxidized heterocyclic compounds). The modeling revealed the limiting step of the process. The increase of hexacyanoferrate(III) reduction rate is determined by the rate of reduced enzymes interaction with oxidized heterocyclic compound. The oxidation of heterocyclic compounds (mediators) with hexacyanoferrate(III) does not limit the process. The analysis of macrokinetics of biosensors action showed that synergistic effect may be realized and high biosensors sensitivity may be achieved if diffusion module of the enzyme reaction with the oxidized mediator and of a cross reaction is larger than 0.5. The calculated relative sensitivity is about three times higher in comparison to experimentally determined that may be caused by the limited stability of oxidized heterocyclic compounds and/or some external diffusion limitation of substrates.
Collapse
Affiliation(s)
- Juozas Kulys
- Institute of Biochemistry, Enzyme Chemistry, Mokslininku 12, LT-08662 Vilnius, Lithuania.
| | | |
Collapse
|
20
|
Krikstopaitis K, Kulys J, Tetianec L. Bioelectrocatalytical glucose oxidation with phenoxazine modified glucose oxidase. Electrochem commun 2004. [DOI: 10.1016/j.elecom.2004.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
|
21
|
Won K, Kim YH, An ES, Lee YS, Song BK. Horseradish Peroxidase-Catalyzed Polymerization of Cardanol in the Presence of Redox Mediators. Biomacromolecules 2003; 5:1-4. [PMID: 14715000 DOI: 10.1021/bm034325u] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Horseradish peroxidase-catalyzed polymerization of cardanol in aqueous organic solvent was investigated in the presence of a redox mediator. Cardanol is a phenol derivative from a renewable resource mainly having a C15 unsaturated hydrocarbon chain with mostly 1-3 double bonds at a meta position. Unlike soybean peroxidase (SBP), it has been shown that horseradish peroxidase (HRP) is not able to perform oxidative polymerization of phenol derivatives having a bulky meta substituent such as cardanol. For the first time, redox mediators have been applied to enable horseradish peroxidase to polymerize cardanol. Veratryl alcohol, N-ethyl phenothiazine, and phenothiazine-10-propionic acid were tested as a mediator. It is surprising that the horseradish peroxidase-catalyzed polymerization of cardanol took place in the presence of N-ethyl phenothiazine or phenothiazine-10-propionic acid. However, veratryl alcohol showed no effect. FT-IR and GPC analysis of the product revealed that the structure and properties of polycardanol formed by HRP with a mediator were similar to those by SBP. This is the first work to apply a redox mediator to enzyme-catalyzed oxidative polymerization. Our new finding that oxidative polymerization of a poor substrate, which the enzyme is not active with, can take place in the presence of an appropriate mediator will present more opportunities for the application of enzyme-catalyzed polymerization.
Collapse
Affiliation(s)
- Keehoon Won
- Korea Research Institute of Chemical Technology, 100 Jang-Dong, Yuseong-Gu, Daejeon 305-343, South Korea
| | | | | | | | | |
Collapse
|
22
|
Kulys J, Vidziunaite R. Amperometric biosensors based on recombinant laccases for phenols determination. Biosens Bioelectron 2003; 18:319-25. [PMID: 12485779 DOI: 10.1016/s0956-5663(02)00172-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Graphite (GE) or printed graphite electrode (PGE) based biosensors containing recombinant fungal laccase Polyporus pinsitus (rPpL), and Myceliophthora thermophila (rMtL) were developed. The enzymes were immobilized using bovine serum albumin and glutaraldehyde. At pH 5.5 and -0.1 V, the calibration graphs of GE based biosensors were hyperbolic if pyrocatechol was used. The concentration of substrate that results in 50% of steady-state response (EC(50)) was 0.7 mM and sensitivity (S) was 3.8 mA/M. The sensitivity increased up to 4 A/M if larger amount of rPpL was used. The sensitivity of biosensors changed little during 9 days of exploitation, but decreased at longer time. The PGE based biosensors were mounted into the flow-through cell and calibrated under kinetic regime. EC(50) of the biosensors containing rPpL varied from 0.6 to 4.0 mM and sensitivity varied from 0.11 to 1.9 mA/M. The response of biosensor containing thermostable laccase rMtL was less, but response saturated at larger pyrocatechol concentration. The sensitivity changed little during 6 days. Both type of biosensors responded also to 1-naphthol, o-phenylenediamine, guaiacol, o-anizidine, benzidine. The experiments demonstrate recombinant laccases application to biosensor engineering and their use to phenol and related compound determination under steady-state and flow-through regimes.
Collapse
Affiliation(s)
- Juozas Kulys
- Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania.
| | | |
Collapse
|
23
|
|
24
|
Barsberg S. Modification phenomena of solid-state lignin caused by electron-abstracting oxidative systems. Arch Biochem Biophys 2002; 404:62-70. [PMID: 12127070 DOI: 10.1016/s0003-9861(02)00225-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Oxidative treatments of wood pulp lignin by one-electron-abstracting enzymatic or chemical systems result in modification phenomena which are not fully described in terms of those known from lignin model compound studies. The generation of, e.g., long-lived radicals necessitates nondestructive spectroscopic analysis of the lignin polymer for a proper characterization of these. The present work exposes a complexity of spectroscopic modification phenomena, which has not previously been realized. This is achieved by a laccase-mediator system, where the mediator is an aromatic low-molecular-weight compound, which mediates the electron abstraction between the lignin and the enzyme laccase. It is demonstrated that the modification generated exhibits qualitatively different temporal phases. The mechanisms are partly explained in terms of Marcus electron transfer theory, and it is suggested that these may play a role in the in vivo synthesis and degradation of lignin.
Collapse
Affiliation(s)
- Søren Barsberg
- Plant Fibre Laboratory, The Royal Veterinary and Agricultural University, 10, Agrovej, DK-2630 Taastrup, Denmark.
| |
Collapse
|
25
|
Kulys J, Deussen HJ, Krikstopaitis K, Lolck R, Schneider P, Ziemys A. N-Arylhydroxamic Acids as Novel Oxidoreductase Substrates. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200109)2001:18<3475::aid-ejoc3475>3.0.co;2-k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
26
|
Kulys J, Ziemys A. A role of proton transfer in peroxidase-catalyzed process elucidated by substrates docking calculations. BMC STRUCTURAL BIOLOGY 2001; 1:3. [PMID: 11545682 PMCID: PMC55340 DOI: 10.1186/1472-6807-1-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2001] [Accepted: 08/28/2001] [Indexed: 11/10/2022]
Abstract
BACKGROUND Previous kinetic investigations of fungal-peroxidase catalyzed oxidation of N-aryl hydroxamic acids (AHAs) and N-aryl-N-hydroxy urethanes (AHUs) revealed that the rate of reaction was independent of the formal redox potential of substrates. Moreover, the oxidation rate was 3-5 orders of magnitude less than for oxidation of physiological phenol substrates, though the redox potential was similar. RESULTS To explain the unexpectedly low reactivity of AHAs and AHUs we made ab initio calculations of the molecular structure of the substrates following in silico docking in the active center of the enzyme. CONCLUSIONS AHAs and AHUs were docked at the distal side of heme in the sites formed by hydrophobic amino acid residues that retarded a proton transfer and finally the oxidation rate. The analogous phenol substrates were docked at different sites permitting fast proton transfer in the relay of distal His and water that helped fast substrate oxidation.
Collapse
Affiliation(s)
- Juozas Kulys
- Department of Enzyme Chemistry, Institute of Biochemistry, Mokslininku 12, Vilnius, 2600, Lithuania
| | - Arturas Ziemys
- Department of Biology, Faculty of Natural Sciences Vytautas Magnus University, Vileikos 8, Kaunas, 3500, Lithuania
| |
Collapse
|