Phenolic and non-phenolic substrates oxidation by laccase at variable oxygen concentrations: Selection of bisubstrate kinetic models from polarographic data

Pinto, Paula A.; Fraga, Irene; Bezerra, Rui M. F.; Dias, Albino A.

doi:10.1016/j.bej.2019.107423

Cited by 14 publications

(5 citation statements)

References 29 publications

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“…Surprisingly, the specific activity of StMCO against DMP was one order of magnitude lower than that of ABTS, which might be attributed to the different bisubstrate reaction mechanism. It was reported that the bisubstrate models of ABTS and DMP oxidation by multicopper oxidases were ping-pong and Theorell-Chance, respectively [35]. Multicopper oxidases, particularly laccase, were able to catalyze reactions involving a broad range of substrates, such as the model substrate 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), lignin-related aromatic compounds, metal ions, and so on [32].…”

Section: Biochemical Characterization Of Purified Recombinant Stmcomentioning

confidence: 99%

Section: Biochemical Characterization Of Purified Recombinant Stmcomentioning

confidence: 99%

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Efficient Degradation of Aflatoxin B1 and Zearalenone by Laccase-like Multicopper Oxidase from Streptomyces thermocarboxydus in the Presence of Mediators

Qin

Xin

Zou

et al. 2021

Toxins

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Multicopper oxidases (MCOs) are a diverse group of enzymes that could catalyze the oxidation of different xenobiotic compounds, with simultaneous reduction in oxygen to water. Aside from laccase, one member of the MCO superfamily has shown great potential in the biodegradation of mycotoxins; however, the mycotoxin degradation ability of other MCOs is uncertain. In this study, a novel MCO-encoding gene, StMCO, from Streptomyces thermocarboxydus, was identified, cloned, and heterologously expressed in Escherichia coli. The purified recombinant StMCO exhibited the characteristic blue color and bivalent copper ion-dependent enzyme activity. It was capable of oxidizing the model substrate ABTS, phenolic compound DMP, and azo dye RB5. Notably, StMCO could directly degrade aflatoxin B1 (AFB1) and zearalenone (ZEN) in the absence of mediators. Meanwhile, the presence of various lignin unit-derived natural mediators or ABTS could significantly accelerate the degradation of AFB1 and ZEN by StMCO. Furthermore, the biological toxicities of their corresponding degradation products, AFQ1 and 13-OH-ZEN-quinone, were remarkably decreased. Our findings suggested that efficient degradation of mycotoxins with mediators might be a common feature of the MCOs superfamily. In summary, the unique properties of MCOs make them good candidates for degrading multiple major mycotoxins in contaminated feed and food.

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Section: Biochemical Characterization Of Purified Recombinant Stmcomentioning

confidence: 99%

Section: Biochemical Characterization Of Purified Recombinant Stmcomentioning

confidence: 99%

Efficient Degradation of Aflatoxin B1 and Zearalenone by Laccase-like Multicopper Oxidase from Streptomyces thermocarboxydus in the Presence of Mediators

Qin

Xin

Zou

et al. 2021

Toxins

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show abstract

“…Once the second substrate binds, the first product is immediately released in a fast reaction while the second product is released in a slow reaction (rate-determining step), as shown in Figure 8. 315 McClard et al introduced a more complex "double Theorell−Chance" mechanism, as evidenced by kinetic results for the homodimeric enzyme, orotate phosphoribosyltransferase (OPRTase) from Saccharomyces cerevisiae. 316 In this mechanism, two substrates, 5-α-D-phoshorylribose 1-diphosphate (PRPP) and orotic acid (OA), are initially bound to one subunit, with the formed products, nucleotide orotidine 5′phosphate (OMP) and diphosphate (PP i ), stacked in the reaction subunit.…”

Section: Dual Ligand-binding Modelsmentioning

confidence: 99%

“…In this model, all substrates are bound and catalyzed initially. Once the second substrate binds, the first product is immediately released in a fast reaction while the second product is released in a slow reaction (rate-determining step), as shown in Figure …”

Section: Cooperativity Of Homodimeric Enzymes In Substrate Bindingmentioning

confidence: 99%

New Insights into the Cooperativity and Dynamics of Dimeric Enzymes

Chen

Sun

2023

Chem. Rev.

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A survey of protein databases indicates that the majority of enzymes exist in oligomeric forms, with about half of those found in the UniProt database being homodimeric. Understanding why many enzymes are in their dimeric form is imperative. Recent developments in experimental and computational techniques have allowed for a deeper comprehension of the cooperative interactions between the subunits of dimeric enzymes. This review aims to succinctly summarize these recent advancements by providing an overview of experimental and theoretical methods, as well as an understanding of cooperativity in substrate binding and the molecular mechanisms of cooperative catalysis within homodimeric enzymes. Focus is set upon the beneficial effects of dimerization and cooperative catalysis. These advancements not only provide essential case studies and theoretical support for comprehending dimeric enzyme catalysis but also serve as a foundation for designing highly efficient catalysts, such as dimeric organic catalysts. Moreover, these developments have significant implications for drug design, as exemplified by Paxlovid, which was designed for the homodimeric main protease of SARS-CoV-2.

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“…Kinetic assays of DMP oxidation using variable initial concentrations of dioxygen were conducted in a closed system, and the depletion rates of dioxygen were measured. As a result, bi-substrate and single-substrate models developed based on the Michaelis-Menten equation were successfully applied to the experimental data [168]. In a similar study, kinetic constants for the oxidation of a homologous series of catechol substrates by tyrosinase have been investigated.…”

Section: Enzymatic Oxidation Kineticmentioning

confidence: 99%

Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

et al. 2021

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Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phenols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating conditions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive potentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly catalyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

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Phenolic and non-phenolic substrates oxidation by laccase at variable oxygen concentrations: Selection of bisubstrate kinetic models from polarographic data

Cited by 14 publications

References 29 publications

Efficient Degradation of Aflatoxin B1 and Zearalenone by Laccase-like Multicopper Oxidase from Streptomyces thermocarboxydus in the Presence of Mediators

Efficient Degradation of Aflatoxin B1 and Zearalenone by Laccase-like Multicopper Oxidase from Streptomyces thermocarboxydus in the Presence of Mediators

New Insights into the Cooperativity and Dynamics of Dimeric Enzymes

Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

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