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1.
Biomolecules ; 11(9)2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34572604

RESUMO

BACKGROUND: Fungal DyP-type peroxidases have so far been described exclusively for basidiomycetes. Moreover, peroxidases from ascomycetes that oxidize Mn2+ ions are yet not known. METHODS: We describe here the physicochemical, biocatalytic, and molecular characterization of a DyP-type peroxidase (DyP, EC 1.11.1.19) from an ascomycetous fungus. RESULTS: The enzyme oxidizes classic peroxidase substrates such as 2,6-DMP but also veratryl alcohol and notably Mn2+ to Mn3+ ions, suggesting a physiological function of this DyP in lignin modification. The KM value (49 µM) indicates that Mn2+ ions bind with high affinity to the XgrDyP protein but their subsequent oxidation into reactive Mn3+ proceeds with moderate efficiency compared to MnPs and VPs. Mn2+ oxidation was most effective at an acidic pH (between 4.0 and 5.0) and a hypothetical surface exposed an Mn2+ binding site comprising three acidic amino acids (two aspartates and one glutamate) could be localized within the hypothetical XgrDyP structure. The oxidation of Mn2+ ions is seemingly supported by four aromatic amino acids that mediate an electron transfer from the surface to the heme center. CONCLUSIONS: Our findings shed new light on the possible involvement of DyP-type peroxidases in lignocellulose degradation, especially by fungi that lack prototypical ligninolytic class II peroxidases.


Assuntos
Ascomicetos/enzimologia , Corantes/metabolismo , Peroxidases/metabolismo , Sítios de Ligação , Cor , Corantes/isolamento & purificação , Espaço Extracelular/enzimologia , Concentração de Íons de Hidrogênio , Cinética , Funções Verossimilhança , Manganês/metabolismo , Modelos Moleculares , Oxirredução , Peroxidases/química , Peroxidases/isolamento & purificação , Filogenia , Espectrofotometria Ultravioleta , Fatores de Tempo
2.
Toxins (Basel) ; 13(1)2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33478106

RESUMO

Little is known about the degradability of mycotoxin deoxynivalenol (DON) by the spent mushroom substrate (SMS)-derived manganese peroxidase (MnP) and lignin peroxidase (LiP) and its potential. The present study investigated the growth inhibition of Fusarium graminearum KR1 and the degradation of DON by MnP and LiP extracted from SMS. The results from the 7-day treatment period showed that mycelium inhibition of F. graminearum KR1 by MnP and LiP were 23.7% and 74.7%, respectively. Deoxynivalenol production in the mycelium of F. graminearum KR1 was undetectable after treatment with 50 U/mL of MnP or LiP for 7 days. N-acetyl-D-glucosamine (GlcNAc) content and chitinase activity both increased in the hyphae of F. graminearum KR1 after treatment with MnP and LiP for 1, 3, and 6 h, respectively. At 12 h, only the LiP-treated group had higher chitinase activity and GlcNAc content than those of the control group (p < 0.05). However, more than 60% of DON degradabilities (0.5 mg/kg, 1 h) were observed under various pH values (2.5, 4.5, and 6.5) in both MnP (50 U/g) and LiP (50 U/g) groups, while DON degradability at 1 mg/kg was 85.5% after 50 U/g of LiP treatment for 7 h in simulated pig gastrointestinal tracts. Similarly, DON degradability at 5 mg/kg was 67.1% after LiP treatment for 4.5 h in simulated poultry gastrointestinal tracts. The present study demonstrated that SMS-extracted peroxidases, particularly LiP, could effectively degrade DON and inhibit the mycelium growth of F. graminearum KR1.


Assuntos
Flammulina/enzimologia , Fusarium/efeitos dos fármacos , Peroxidases/farmacologia , Tricotecenos/metabolismo , Animais , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Biodegradação Ambiental , Parede Celular/efeitos dos fármacos , Contaminação de Alimentos , Proteínas Fúngicas/isolamento & purificação , Proteínas Fúngicas/farmacologia , Suco Gástrico , Concentração de Íons de Hidrogênio , Modelos Biológicos , Micélio , Micotoxinas/metabolismo , Peroxidases/isolamento & purificação , Aves Domésticas , Suínos
3.
Sci Rep ; 10(1): 8007, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32409642

RESUMO

In this study, peroxidase from Ziziphus jujuba was purified using ion exchange, and gel filtration chromatography resulting in an 18.9-fold enhancement of activity with a recovery of 20%. The molecular weight of Z. jujuba peroxidase was 56 kDa, as estimated by Sephacryl S-200. The purity was evaluated by SDS, which showed a single prominent band. The optimal activity of the peroxidase was achieved at pH 7.5 and 50 °C. Z. jujuba peroxidase showed catalytic efficiency (Kcat/Km) values of 25 and 43 for guaiacol and H2O2, respectively. It was completely inactivated when incubated with ß-mercaptoethanol for 15 min. Hg2+, Zn2+, Cd2+, and NaN3 (5 mM) were effective peroxidase inhibitors, whereas Cu2+ and Ca2+ enhanced the peroxidase activity. The activation energy (Ea) for substrate hydrolysis was 43.89 kJ mol-1, while the Z value and temperature quotient (Q10) were found to be 17.3 °C and 2, respectively. The half-life of the peroxidase was between 117.46 and 14.15 min. For denaturation of the peroxidase, the activation energy for irreversible inactivation Ea*(d) was 120.9 kJmol-1. Thermodynamic experiments suggested a non-spontaneous (∆G*d > 0) and endothermic reaction phase. Other thermodynamic parameters of the irreversible inactivation of the purified enzyme, such as ∆H* and ∆S*, were also studied. Based on these results, the purified peroxidase has a potential role in some industrial applications.


Assuntos
Frutas/enzimologia , Peroxidases/química , Peroxidases/isolamento & purificação , Ziziphus/enzimologia , Algoritmos , Catálise , Fracionamento Químico , Fenômenos Químicos , Ativação Enzimática , Cinética , Modelos Teóricos , Peso Molecular , Termodinâmica
4.
Int J Mol Sci ; 21(2)2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31936493

RESUMO

Manganese peroxidases (MnP) from the white-rot fungi Phanerochaete chrysosporium catalyse the oxidation of Mn2+ to Mn3+, a strong oxidizer able to oxidize a wide variety of organic compounds. Different approaches have been used to unravel the enzymatic properties and potential applications of MnP. However, these efforts have been hampered by the limited production of native MnP by fungi. Heterologous expression of MnP has been achieved in both eukaryotic and prokaryotic expression systems, although with limited production and many disadvantages in the process. Here we described a novel molecular approach for the expression and purification of manganese peroxidase isoform 1 (MnP1) from P. chrysosporium using an E. coli-expression system. The proposed strategy involved the codon optimization and chemical synthesis of the MnP1 gene for optimised expression in the E. coli T7 shuffle host. Recombinant MnP1 (rMnP1) was expressed as a fusion protein, which was recovered from solubilised inclusion bodies. rMnP1 was purified from the fusion protein using intein-based protein purification techniques and a one-step affinity chromatography. The designated strategy allowed production of an active enzyme able to oxidize guaiacol or Mn2+.


Assuntos
Escherichia coli/metabolismo , Expressão Gênica , Peroxidases/isolamento & purificação , Phanerochaete/enzimologia , Sequência de Aminoácidos , Ensaios Enzimáticos , Vetores Genéticos/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Padrões de Referência , Solubilidade
5.
Curr Protein Pept Sci ; 21(5): 497-506, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31746293

RESUMO

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants' defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.


Assuntos
Antifúngicos/farmacologia , Quitinases/farmacologia , Látex/química , Peptídeo Hidrolases/farmacologia , Peroxidases/farmacologia , Lectinas de Plantas/farmacologia , Proteínas de Plantas/farmacologia , Antifúngicos/classificação , Antifúngicos/isolamento & purificação , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Quitinases/classificação , Quitinases/isolamento & purificação , Quitinases/fisiologia , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Ponto Isoelétrico , Testes de Sensibilidade Microbiana , Peso Molecular , Peptídeo Hidrolases/classificação , Peptídeo Hidrolases/isolamento & purificação , Peptídeo Hidrolases/fisiologia , Peroxidases/classificação , Peroxidases/isolamento & purificação , Peroxidases/fisiologia , Doenças das Plantas/microbiologia , Extratos Vegetais/química , Lectinas de Plantas/classificação , Lectinas de Plantas/isolamento & purificação , Lectinas de Plantas/fisiologia , Proteínas de Plantas/classificação , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/fisiologia , Plantas/química
6.
J Hazard Mater ; 386: 121954, 2020 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-31884363

RESUMO

The present study deals with optimizing, producing, characterizing, application and techno- economic analysis of oxidative enzymes [Laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP)] from Aspergillus iizukae EAN605 in submerged fermentation process using pumpkin peels as a production substrate. The best operating parameters for producing Lac, MnP and LiP (6.15, 2.58 and 127.99 U mg-1 respectively) were recorded with 20 g 100 mL-1 of substrate, 4.6 mL 100 mL-1 of inoculum size at pH 5.5 after 10 days. The crude enzyme exhibited high stability at pH (3-9) and temperatures (20-60 °C). Km (Michaelis-Menten) of Lac, MnP and LiP crude enzyme was 2.25, 1.79 and 0.72 mM respectively. The decolourization of Remazol Brilliant Blue R by the crude enzyme was 84.84 %. The techno-economic analysis was assessed for a production unit with an annual operating time for enzymatic production and application is 7920 h/year and 100 m3 of the capacity. The process would produce 27,000 cm3 of crude enzyme with a price of USD 0.107 per cm3 compared to USD 1 per cm3 of the current commercial enzyme. The findings indicated that pumpkin peels have potential as a production substrate for oxidative enzymes from A. iizukae EAN605 and is economically feasible.


Assuntos
Aspergillus/enzimologia , Reatores Biológicos/microbiologia , Cucurbita/química , Lacase/isolamento & purificação , Peroxidases/isolamento & purificação , Reatores Biológicos/economia , Celulose/química , Análise Custo-Benefício , Fermentação , Especificidade por Substrato
7.
Int J Biol Macromol ; 138: 433-440, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325503

RESUMO

Lignin peroxidase (LiP) was obtained from Pichia methanolica through heterologous expression. LiP was extracted, purified, and immobilized on Fe3O4@SiO2@polydopamine (PDA) nanoparticles to acquire immobilized LiP. The optimal preparation conditions for immobilized LiP were investigated. Results showed that the immobilization efficiency of immobilized LiP reached 56.37% when the enzyme amount, PDA concentration, and immobilization time were 12 mg, 1.6 mg/mL, and 12 h, respectively. Compared with free LiP, the immobilized LiP showed good thermal stability and storage stability and improved pH tolerance. It also retained more than 30% of its initial activity after 8 cycles, demonstrating its improved reusability. The immobilized LiP demonstrated efficacy of reaction of 100%, 100%, 100%, 100%, 79%, 73%, and 65% for tetracycline, dibutyl phthalate, 5-chlorophenol, phenol, phenanthrene, fluoranthene, and benzo(a)pyrene, respectively, while the inactivated immobilized LiP only adsorbed <25% of phenanthrene and fluoranthene. The dissipation of organic pollutants was a combination of degradation and adsorption, with the former playing a more important role.


Assuntos
Poluentes Ambientais/química , Enzimas Imobilizadas , Indóis/química , Nanopartículas de Magnetita , Compostos Orgânicos/química , Peroxidases/química , Polímeros/química , Dióxido de Silício , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Nanopartículas de Magnetita/química , Estrutura Molecular , Peroxidases/isolamento & purificação , Dióxido de Silício/química , Temperatura
8.
Appl Biochem Biotechnol ; 189(2): 576-588, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31069629

RESUMO

In this study, peroxidases (PODs) from three waste by-products: broad bean pods (BBP), pea pods (PP), and artichoke stems (ARS) were purified and their optimal conditions were determined for the first time. The purification process resulted in 4.32, 7.21, and 8.9% of POD recoveries for PP, ARS, and BBP, respectively. They were purified 2.12-, 32.97-, and 10-fold with specific activities of 27.26, 266.43, and 27 U/mg of protein, respectively. Analysis of their optimal conditions showed that POD purified from BBP and PP exhibited the highest activity at 60 °C temperature and pH 6 and 8 with strong affinity with catechol substrate (Km of 0.356 and 0.189 mM; Vmax of 0.08 and 0.041 µM/min for BBP and PP, respectively). The highest activity of ARS POD was obtained under the following conditions: temperature at 50 °C, pH from 6 to 8, and guaiacol as substrate (Km 0.375 mM; Vmax 0.012 µM/min). Apart from giving the opportunity for recycling the food industry wastes, the studied waste by-products could represent an alternative source of PODs that could find several applications in the biotechnological, chemical, and food industries.


Assuntos
Cynara scolymus/enzimologia , Peroxidases/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Resíduos , Peroxidases/química , Proteínas de Plantas/química
9.
Sci Rep ; 9(1): 4923, 2019 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-30894631

RESUMO

The genus Agrilus comprises diverse exotic and agriculturally important wood-boring insects that have evolved efficient digestive systems. Agrilus mali Matsumara, an invasive insect, is causing extensive mortality to endangered wild apple trees in Tianshan. In this study, we present an in-depth characterization of the gut microbiota of A. mali based on high-throughput sequencing of the 16S rRNA gene and report the presence of lignocellulose-degrading bacteria. Thirty-nine operational taxonomic units (OTUs) were characterized from the larval gut. OTUs represented 6 phyla, 10 classes, 16 orders, 20 families, and 20 genera. The majority of bacterial OTUs belonged to the order Enterobacteriales which was the most abundant taxa in the larval gut. Cultivable bacteria revealed 9 OTUs that all belonged to Gammaproteobacteria. Subsequently, we examined the breakdown of plant cell-wall compounds by bacterial isolates. Among the isolates, the highest efficiency was observed in Pantoea sp., which was able to synthesize four out of the six enzymes (cellulase, cellobiase, ß-xylanase, and ß-gluconase) responsible for plant-cell wall degradation. One isolate identified as Pseudomonas orientalis exhibited lignin peroxidase activity. Our study provides the first characterization of the gut microbial diversity of A. mali larvae and shows that some cultivable bacteria play a significant role in the digestive tracts of larvae by providing nutritional needs.


Assuntos
Parede Celular/química , Besouros/microbiologia , Enterobacteriaceae/enzimologia , Gammaproteobacteria/enzimologia , Microbioma Gastrointestinal/genética , Malus/parasitologia , Filogenia , Animais , Proteínas de Bactérias , Biodiversidade , Parede Celular/parasitologia , Celulase/genética , Celulase/isolamento & purificação , Celulase/metabolismo , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/isolamento & purificação , Endo-1,4-beta-Xilanases/metabolismo , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Gammaproteobacteria/classificação , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Trato Gastrointestinal/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala , Larva/microbiologia , Lignina/metabolismo , Malus/química , Peroxidases/genética , Peroxidases/isolamento & purificação , Peroxidases/metabolismo , Células Vegetais/química , Células Vegetais/parasitologia , RNA Ribossômico 16S/genética , Madeira/química , Madeira/parasitologia , beta-Glucosidase/genética , beta-Glucosidase/isolamento & purificação , beta-Glucosidase/metabolismo
10.
Sci Rep ; 9(1): 3769, 2019 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-30842542

RESUMO

Sweet potato (Ipomoea batatas L.) is the sixth most important food crop in the world. The industry discarded huge amount of sweet potato stems, rich of peroxidases and phenolics. A simple procedure was developed to make peroxidases and phenolics from sweet potato old stems. Dried stem powder was loaded into columns with water and eluted sequentially with water and 50% ethanol. Peroxidases (91%) were extracted in 5.5-fold water extracts and 87% phenolics were extracted in 4.4-fold ethanol extracts. Purified peroxidases powder was yielded at 3.1 g (8.6 unit/mg) per kilogram stems by PEG6000/Na2SO4 aqueous two-phase purification from the water extracts (93.2% recovery), followed by ethanol precipitation and vacuum freeze-drying. The purified peroxidase had high activity in transforming tea catechins into theaflavins. Phenolics powder containing 43% phenolics and 27% flavonoids was yielded at 76.9 g per kilogram stems after vacuum-concentrating the ethanol extracts. This method can make valuable functional products using the sweet potato waste.


Assuntos
Ipomoea batatas/metabolismo , Peroxidases/isolamento & purificação , Fenóis/isolamento & purificação , Proteínas de Bactérias/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Manipulação de Alimentos , Congelamento , Caules de Planta/metabolismo
11.
J Am Chem Soc ; 140(51): 17840-17845, 2018 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-30525563

RESUMO

The biosynthetic route to the napyradiomycin family of bacterial meroterpenoids has been fully described 32 years following their original isolation and 11 years after their gene cluster discovery. The antimicrobial and cytotoxic natural products napyradiomycins A1 and B1 are produced using three organic substrates (1,3,6,8-tetrahydroxynaphthalene, dimethylallyl pyrophosphate, and geranyl pyrophosphate), and catalysis via five enzymes: two aromatic prenyltransferases (NapT8 and T9); and three vanadium dependent haloperoxidase (VHPO) homologues (NapH1, H3, and H4). Building upon the previous characterization of NapH1, H3, and T8, we herein describe the initial (NapT9, H1) and final (NapH4) steps required for napyradiomycin construction. This remarkably streamlined biosynthesis highlights the utility of VHPO enzymology in complex natural product generation, as NapH4 efficiently performs a unique chloronium-induced terpenoid cyclization to establish two stereocenters and a new carbon-carbon bond, and dual-acting NapH1 catalyzes chlorination and etherification reactions at two distinct stages of the pathway. Moreover, we employed recombinant napyradiomycin biosynthetic enzymes to chemoenzymatically synthesize milligram quantities in one pot in 1 day. This method represents a viable enantioselective approach to produce complex halogenated metabolites, like napyradiomycin B1, that have yet to be chemically synthesized.


Assuntos
Antibacterianos/síntese química , Proteínas de Bactérias/química , Dimetilaliltranstransferase/química , Peroxidases/química , Proteínas de Bactérias/isolamento & purificação , Biocatálise , Dimetilaliltranstransferase/isolamento & purificação , Naftoquinonas/síntese química , Peroxidases/isolamento & purificação , Streptomyces/enzimologia
12.
Methods Enzymol ; 605: 141-201, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29909824

RESUMO

Vanadium-dependent haloperoxidases in seaweeds, cyanobacteria, fungi, and possibly phytoplankton play an important role in the release of halogenated volatile compounds in the environment. These halocarbons have effects on atmospheric chemistry since they cause ozone depletion. In this chapter, a survey is given of the different sources of these enzymes, some of their properties, the various methods to isolate them, and the bottlenecks in purification. The assays to detect and quantify haloperoxidase activity are described as well as their kinetic properties. Several practical tips and pitfalls are given which have not yet been published explicitly. Recent developments in research on structure and function of these enzymes are reviewed. Finally, the application of vanadium-dependent haloperoxidases in the biosynthesis of brominated and other compounds is discussed.


Assuntos
Organismos Aquáticos/metabolismo , Cloreto Peroxidase/isolamento & purificação , Ensaios Enzimáticos/métodos , Iodeto Peroxidase/isolamento & purificação , Peroxidases/isolamento & purificação , Organismos Aquáticos/química , Cloreto Peroxidase/química , Cloreto Peroxidase/metabolismo , Química Verde/métodos , Iodeto Peroxidase/química , Iodeto Peroxidase/metabolismo , Peroxidases/química , Peroxidases/metabolismo
13.
Methods Enzymol ; 605: 51-68, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29909837

RESUMO

Catalase-related allene oxide synthase (cAOS) is a hemoprotein that converts a specific fatty acid hydroperoxide to an unstable allene oxide intermediate at turnover rates in the order of 1000 per second. Fatty acid allene oxides are intermediates in the formation of cyclopentenone or hydrolytic products in marine systems, most notably the prostanoid-related clavulones. Although the key catalytic amino acid residues around the active site of cAOS are the same as in true catalases, cAOS does not react with hydrogen peroxide. cAOS occurs exclusively as the N-terminal domain of a naturally occurring fusion protein with a C-terminal lipoxygenase (LOX) domain that supplies the hydroperoxide substrate. In marine invertebrates, an 8R-LOX domain converts arachidonic acid to 8R-hydroperoxyeicosatetraenoic acid (8R-HPETE) and the cAOS domain forms an 8,9-epoxy allene oxide. The fusion protein from the sea whip octocoral Plexaura homomalla is the prototypical model with crystal structures of the individual domains. The cAOS (43kDa) expresses exceptionally well in Escherichia coli, with yields of up to 100mg/L. This article describes in detail expression and assay of the P. homomalla cAOS and two methods for the preparation of its 8R-HPETE substrate. Another article in this volume focuses on the P. homomalla 8R-LOX (Gilbert, Neau, & Newcomer, 2018).


Assuntos
Antozoários/metabolismo , Ensaios Enzimáticos/métodos , Hemeproteínas/metabolismo , Leucotrienos/síntese química , Lipoxigenase/metabolismo , Peroxidases/metabolismo , Animais , Ácido Araquidônico/química , Domínio Catalítico/genética , Cromatografia Líquida/instrumentação , Cromatografia Líquida/métodos , Ciclopentanos/metabolismo , Escherichia coli/metabolismo , Hemeproteínas/genética , Hemeproteínas/isolamento & purificação , Peróxido de Hidrogênio/química , Leucotrienos/metabolismo , Lipoxigenase/genética , Lipoxigenase/isolamento & purificação , Oxirredução , Peroxidases/genética , Peroxidases/isolamento & purificação , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo
14.
Int J Biol Macromol ; 114: 898-905, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29626603

RESUMO

Peroxidase (POD) from jackfruit bulb was purified using ammonium sulfate precipitation, hydrophobic interaction and gel filtration columns. The POD was a dimer with a molecular weight of 104kDa. The Km and Vmax values for guaiacol, gallic acid and o­phenylenediamine (OPD) were estimated. OPD was the most suitable substrate. The enzyme showed its maximum activity at pH5.5 and 55-60°C. The activation energy (Ea) of heat inactivation was estimated to be 206.40kJ/mol. The enthalpy, free energy and entropy values for the thermal inactivation were also determined. The POD activity was enhanced by K+, Zn2+, Ba2+, citric acid, malic acid, benzoic acid and EDTA·Na2, but inhibited by Cu2+, Ca2+, glutathione, cysteine and ascorbic acid. Chemical modification indicated a histidine residue was located in the enzyme active site. The POD activity in fruit extracts significantly decreased when heated at 80°C and 90°C. The ferric-reducing antioxidant power, ABTS radical scavenging activity and total phenolics decreased with increasing heating temperature and time.


Assuntos
Artocarpus/enzimologia , Peroxidases/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Catecol Oxidase/antagonistas & inibidores , Catecol Oxidase/isolamento & purificação , Catecol Oxidase/farmacologia , Cátions/farmacologia , Inibidores Enzimáticos/farmacologia , Aditivos Alimentares/farmacologia , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Temperatura Alta , Concentração de Íons de Hidrogênio , Cinética , Peso Molecular , Oxirredução , Peroxidases/antagonistas & inibidores , Peroxidases/farmacologia , Fenóis/análise , Proteínas de Plantas/agonistas , Proteínas de Plantas/antagonistas & inibidores , Proteínas de Plantas/farmacologia , Raízes de Plantas/enzimologia , Estabilidade Proteica , Especificidade por Substrato
15.
Enzyme Microb Technol ; 111: 81-86, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29421042

RESUMO

Synthesis of nanoparticles is an enzymatic reduction process in microorganisms. In the present study, a protein, lignin peroxidase has been purified by DEAE-Cellulose anion exchange chromatography and Biogel P-150 gel filtration chromatography from the cell suspension of Acinetobacter sp. SW30 responsible for the synthesis of gold nanoparticles (AuNP) and selenium nanoparticles (SeNP). The purified fraction has a specific activity of 29.4U/mg/min with 959 fold purification. Native and SDS PAGE confirmed that purified lignin peroxidase is monomeric enzyme with 97.4KDa molecular weight. The enzyme synthesized spherical crystalline AuNP (10±2nm) and amorphous SeNP (100±10nm). It has maximum activity at pH 2 and temperature 40°C, with 1.0mMKm value, when n-propanol was used as a substrate. Activity was completely inhibited by sodium thiosulphate and zinc sulphate. This is the first report on association of lignin peroxidase in the synthesis of AuNP and SeNP from Acinetobacter sp. SW30.


Assuntos
Acinetobacter/enzimologia , Proteínas de Bactérias/metabolismo , Ouro/metabolismo , Nanopartículas Metálicas/química , Nanopartículas/metabolismo , Peroxidases/metabolismo , Selênio/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Peso Molecular , Nanotecnologia , Peroxidases/química , Peroxidases/isolamento & purificação , Especificidade por Substrato
16.
Int J Biol Macromol ; 106: 636-646, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28813685

RESUMO

Two extracellular peroxidases from Bjerkandera adusta strain CX-9, namely a lignin peroxidase (called LiP BA45) and manganese peroxidase (called MnP BA30), were purified simultaneously by applying successively, ammonium sulfate precipitation-dialysis, Mono-S Sepharose anion-exchange and Sephacryl S-200 gel filtration and biochemically characterized. The sequence of their NH2-terminal amino acid residues showed high homology with those of fungi peroxidases. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzymes MnP BA30 and LiP BA45 were a monomers with a molecular masses 30125.16 and 45221.10Da, respectively. While MnP BA30 was optimally active at pH 3 and 70°C, LiP BA45 showed optimum activity at pH 4 and 50°C. The two enzymes were inhibited by sodium azide and potassium cyanide, suggesting the presence of heme-components in their tertiary structures. The Km and Vmax for LiP BA45 toward 2,4-Dichlorolphenol (2,4-DCP) were 0.099mM and 9.12U/mg, respectively and for MnP BA30 toward 2,6-Dimethylphenol (2,6-DMP), they were 0.151mM and 18.60U/mg, respectively. Interestingly, MnP BA30 and LiP BA45 demonstrated higher catalytic efficiency than that of other tested peroxidases (MnP, LiP, HaP4, and LiP-SN) and marked organic solvent-stability and dye-decolorization efficiency. Data suggest that these peroxidases may be considered as potential candidates for future applications in distaining synthetic-dyes.


Assuntos
Clorofenóis/metabolismo , Coriolaceae/enzimologia , Proteínas Fúngicas/metabolismo , Lignina/metabolismo , Peroxidases/metabolismo , Xilenos/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Corantes/metabolismo , Coriolaceae/genética , Ensaios Enzimáticos , Estabilidade Enzimática , Proteínas Fúngicas/genética , Proteínas Fúngicas/isolamento & purificação , Expressão Gênica , Temperatura Alta , Concentração de Íons de Hidrogênio , Cinética , Peso Molecular , Peroxidases/genética , Peroxidases/isolamento & purificação , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
17.
J Biol Inorg Chem ; 23(2): 209-219, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29170897

RESUMO

Possessing both peroxidase and peroxygenase activities with a broad substrate profile that includes phenols, indoles, and pyrroles, the enzyme dehaloperoxidase (DHP) from Amphitrite ornata is a multifunctional catalytic hemoglobin that challenges many of the assumptions behind the well-established structure-function paradigm in hemoproteins. While previous studies have demonstrated that the F21W variant leads to attenuated peroxidase activity in DHP, here we have studied the impact of this mutation on peroxygenase activity to determine if it is possible to selectively tune DHP to favor one function over another. Biochemical assays with DHP B (F21W) revealed minimal decreases in peroxygenase activity of 1.2-2.1-fold as measured by 4-nitrophenol or 5-Br-indole substrate conversion, whereas the peroxidase activity catalytic efficiency for 2,4,6-trichlorophenol (TCP) was more than sevenfold decreased. Binding studies showed a 20-fold weaker affinity for 5-bromoindole (K d = 2960 ± 940 µM) in DHP B (F21W) compared to WT DHP B. Stopped-flow UV/visible studies and isotope labeling experiments together suggest that the F21W mutation neither significantly changes the nature of the catalytic intermediates, nor alters the mechanisms that have been established for peroxidase and peroxygenase activities in DHP. The X-ray crystal structure (1.96 Å; PDB 5VLX) of DHP B (F21W) revealed that the tryptophan blocks one of the two identified TCP binding sites, specifically TCPinterior, suggesting that the other site, TCPexterior, remains viable for binding peroxygenase substrates. Taken together, these studies demonstrate that blocking the TCPinterior binding site in DHP selectively favors peroxygenase activity at the expense of its peroxidase activity.


Assuntos
Hemoglobinas/metabolismo , Mutação , Peroxidases/metabolismo , Poliquetos/enzimologia , Animais , Catálise , Cristalografia por Raios X , Hemoglobinas/química , Hemoglobinas/genética , Hemoglobinas/isolamento & purificação , Peroxidases/química , Peroxidases/genética , Peroxidases/isolamento & purificação , Espectrofotometria Ultravioleta , Especificidade por Substrato
18.
Talanta ; 169: 130-135, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28411802

RESUMO

Protein mixtures were separated using tube radial distribution chromatography (TRDC) in a polytetrafluoroethylene (PTFE) capillary (internal diameter=100µm) separation tube. Separation by TRDC is based on the annular flow in phase separation multiphase flow and features an open-tube capillary without the use of specific packing agents or application of high voltages. Preliminary experiments were conducted to examine the effects of pH and salt concentration on the phase diagram of the ternary mixed solvent solution of water-acetonitrile-ethyl acetate (8:2:1 volume ratio) and on the TRDC system using the ternary mixed solvent solution. A model protein mixture containing peroxidase, lysozyme, and bovine serum albumin was analyzed via TRDC with the ternary mixed solvent solution at various pH values, i.e., buffer-acetonitrile-ethyl acetate (8:2:1 volume ratio). Protein was separated on the chromatograms by the TRDC system, where the elution order was determined by the relation between the isoelectric points of protein and the pH values of the solvent solution.


Assuntos
Eletrocromatografia Capilar/métodos , Muramidase/isolamento & purificação , Peroxidases/isolamento & purificação , Politetrafluoretileno/química , Soroalbumina Bovina/isolamento & purificação , Cloreto de Sódio/química , Animais , Bovinos , Humanos , Concentração de Íons de Hidrogênio , Muramidase/química , Peroxidases/química , Transição de Fase , Soroalbumina Bovina/química
19.
Curr Protein Pept Sci ; 18(8): 864-880, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28393701

RESUMO

The aim of this review is to cover most recent research on plant pathogenesis- and defenserelated proteins from latex-bearing medicinal plant Chelidonium majus (Papaveraceae) in the context of its importance for latex activity, function, pharmacological activities, and antiviral medicinal use. These results are compared with other latex-bearing plant species and recent research on proteins and chemical compounds contained in their latex. This is the first review, which clearly summarizes pathogenesisrelated (PR) protein families in latex-bearing plants pointing into their possible functions. The possible antiviral function of the latex by naming the abundant proteins present therein is also emphasized. Finally latex-borne defense system is hypothesized to constitute a novel type of preformed immediate defense response against viral, but also non-viral pathogens, and herbivores.


Assuntos
Antivirais/química , Chelidonium/química , Látex/química , Proteínas de Plantas/química , Alcaloides/química , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Antivirais/isolamento & purificação , Antivirais/farmacologia , Benzilisoquinolinas/química , Benzilisoquinolinas/isolamento & purificação , Benzilisoquinolinas/farmacologia , Catecol Oxidase/química , Catecol Oxidase/isolamento & purificação , Catecol Oxidase/farmacologia , Quitinases/química , Quitinases/isolamento & purificação , Quitinases/farmacologia , Endopeptidases/química , Endopeptidases/isolamento & purificação , Endopeptidases/farmacologia , Lipoxigenase/química , Lipoxigenase/isolamento & purificação , Lipoxigenase/farmacologia , Peroxidases/química , Peroxidases/isolamento & purificação , Peroxidases/farmacologia , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/farmacologia , Ribonucleases/química , Ribonucleases/isolamento & purificação , Ribonucleases/farmacologia , Replicação Viral/efeitos dos fármacos
20.
J Biosci Bioeng ; 124(1): 91-98, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28319022

RESUMO

Amauroderma rugosum is a wild mushroom species widely distributed in tropics and is classified under the class of Basidiomycetes. Basidiomycetes are well-known for their abilities of producing lignocellulolytic enzymes such as lignin peroxidase (LiP), laccase (Lac) and manganese peroxidase (MnP). Different factors such as nutrient sources, incubation period and agitation affect the production of lignocellulolytic enzymes. The A. rugosum produced LiP in the medium supplemented with potato dextrose broth (PDB), 0.5% yeast and 1.0% saw dust at 26.70±3.31 U/mL. However, the LiP activity was increased to 106.32±5.32 U/mL when supplemented with 150 µm of copper (CuSO4). The aqueous two-phase system (ATPS) is a simple, rapid and low cost method for primary extraction and recovery of LiP. A total of 25 systems made from five different molecular weights of polyethylene glycol (PEG)/dipotassium hydrogen phosphate (K2HPO4) were tested. PEG 600 produced the highest top phase purification factor (PFT) of 1.33±0.62 with yield of 72.18±8.50%. The optimization of the ATPS parameters, such as volume ratio VR, pH and crude enzyme loading are the factors controlling the phase partition. Our results showed that significant improvement (PFT of 6.26±2.87 with yield of 87.31±3.14%) of LiP recovery can be achieved by optimized the parameters.


Assuntos
Fracionamento Químico/métodos , Fermentação , Peroxidases/isolamento & purificação , Polietilenoglicóis/química , Polyporales/metabolismo , Água/química , Imersão , Peso Molecular , Peroxidases/biossíntese , Peroxidases/química , Cloreto de Sódio/química
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