Oxidoreductase Enzymes Research Articles

Evaluating the Sulfur Oxidation Capability of a Rhodopseudomonas palustris Strain by Gene and Enzyme Analyses for Potential Applications in Environmental Bioremediation

Sulfur-oxidizing bacteria are capable of oxidizing various sulfur compounds including sulfide and thiosulfate in the environment. Hydrogen sulfide (H2S), a product of anaerobic decomposition, is highly corrosive. With the typical smell of rotten eggs, the toxic gas H2S causes many harmful effects on the environment and human health. Sulfide:quinone oxidoreductase enzyme (SQR) produced by sulfur-oxidizing bacteria plays an important role in the sulfide oxidation process, contributing to minimizing sulfide toxicity in the environment. In this study, the presence of sqr gene and SQR enzyme in the photosynthetic purple bacterium Rhodopseudomonas palustris (R. palustris) isolated from domestic wastewater was determined by gene amplification (PCR) using specific primer pairs following by sequencing and denaturing SDS-PAGE method combined with sulfide oxidase assay that measures BaSO4 turbidity, respectively. The results showed that the sqr gene has 1254 bp in length, encoding for the SQR protein containing 417 amino acids with a molecular weight of 45.87 kDa and locating on the cell membrane. The enzyme operated optimally under the condition of pH 6.5 and temperature at 30 °C with sulfide oxidation activity recorded up to 20-21 U/ml. The study has initially shown the ability of the R. palustris bacterial strain to oxidize sulfide for further research using sulfur-oxidizing bacteria applied in environmental treatment.

Dynamic Changes in Pectin Composition, Flesh Firmness and Oxidoreductase Enzymes Across Different Stages of Fruit Development in Loquat Cultivars

Dynamic Changes in Pectin Composition, Flesh Firmness and Oxidoreductase Enzymes Across Different Stages of Fruit Development in Loquat Cultivars

The Transformative Potential of Oxidoreductases in Pollutant Remediation – A Review

: In this modern era, the environment is being contaminated with toxic pollutants as a result of anthropogenic activities. To overcome the harmful effects of pollutants, scientists have developed ideas and technologies. Biotechnology provides a green approach for decontaminating the environment, i.e., bioremediation. Several organisms have been explored for their enzymes. Enzymes belonging to various classes are useful for degrading, transforming, or removal of pollutants. Oxidoreductases produced by different plants, bacteria, and fungi are useful for deterioration of toxic pollutants, like compounds having aroma, called aromatic compounds (benzene, chlorine, phenols, phenanthrene, etc.), PAHs (Polyaromatic Hydrocarbons), various dyes, etc. Oxidoreductases are further classified as laccases, peroxidases, and oxygenases. All three classes have proven to be efficacious in the field of bioremediation. Microorganism strains have also been genetically engineered for the production of enzymes. Oxidoreductases can be used to remove pollutants from industrial waste. This review has classified all the species that produce oxidoreductase enzymes, their mechanism of action, and the pollutants that have been removed by using oxidoreductases.

Active-matrix extended-gate field-effect transistor array for simultaneous detection of multiple metabolites

With the deepening understanding of diseases, increasing attention has been paid to personalized healthcare and precise diagnosis, which usually depend on the simultaneous monitoring of multiple metabolites, therefore requiring biological sensing systems to possess high sensitivity, specificity, throughput, and instant monitoring capabilities. In this work, we demonstrated the active-matrix extended-gate field-effect transistor (AMEGFET) array that can perform instant analysis of various metabolites in small amounts of body fluids collected during routine physiological activities. The extended gate electrodes of the AMEGFETs comprise ordered mesoporous carbon fibers loaded with both oxidoreductase enzymes for specific metabolites and platinum nanoparticles. By selecting customized electrode combinations, the AMEGFET array can monitor the concentrations of metabolites closely associated with chronic diseases and lifestyles, such as glucose, uric acid, cholesterol, ethanol, and lactate. The switch function of AMEGFET not only simplifies the readout circuitry for large-scale arrays but also avoids the mutual interferences among sensing units. The high flexibility and scalability make the AMEGFET array widely applicable in establishing high-throughput sensing platforms for biomarkers, providing highly efficient technical support for proactive health and intelligent healthcare.

Rapid achievement of partial nitrification process by adopting the combined strategy of anoxic starvation and free ammonia inhibition

ABSTRACT Partial nitrification (PN) is a prerequisite step for the short-cut nitrogen removal process, which is crucial to provide stable nitrite accumulation for subsequent units. The present study innovatively proposed a new strategy for the rapid establishment of PN by adopting short-term anoxic starvation combined with high free ammonia inhibition. The sludge obtained from the secondary sedimentation tank of a municipal wastewater treatment plant was starved for 7 days under anoxic conditions, and then wastewater with high ammonia nitrogen (400 mg L−1) was introduced. Within 17 days, stable nitrite accumulation was achieved in the sequencing batch reactor, and the nitrite accumulation rate reached more than 95.0%. The activity of ammonia monooxygenase enzyme increased from 0.0364 ± 0.0074 to 0.1275 ± 0.0021 μg NO2 −-N·mg−1 protein min−1, while that of hydroxylamine oxidoreductase enzyme increased from 1.5350 ± 0.0208 to 6.3852 ± 0.0400 EU g−1 SS. The relative abundance of Nitrosomonas increased from 0.10% to 25.90%, while that of Nitrospira consistently remained below 0.04%. And the relative abundance of short-cut denitrifying bacteria, including Truepera, OLB8, and OLB13 all increased. The results proved that the short-term anoxic starvation combined with high free ammonia inhibition was an effective strategy for rapid establishment of PN.

The Roles of Glutaredoxins in Wheat (Triticum aestivum L.) under Biotic and Abiotic Stress Conditions, including Fungal and Hormone Treatments

Glutaredoxins (GRXs) are widely distributed oxidoreductase enzymes that play important roles in plant growth, development, and responses to various stresses. In this study, bioinformatics methods were used to identify and analyze the wheat GRX gene family and predict their properties and potential functions. RNA-seq and RT-qPCR expression analyses were used to investigate their regulatory functions under hormone treatment and fungal diseases. In this study, 86 GRX genes were identified in wheat and classified into CC-type, CGFS-type, and CPYC-type categories with no TaGRX located on chromosome 4B. The results show that TaGRXs regulate wheat transcriptional responses and have an integrative role in biotic and abiotic stress responses. TaGRXs are involved in wheat responses to Fusarium graminearum, Puccinia striiformis, and Erysiphe graminis diseases. TaGRX73-7D, TaGRX20-3A, and TaGRX29-3B play a negative regulatory role in E. graminis infection but a positive regulatory role in F. graminearum and P. striiformis infection. These TaGRXs play potential regulatory functions in wheat responses to the plant hormones and signaling molecules, including IAA, ABA, H2O2, and SA. The findings of this study lay the groundwork for further investigation of the functions of wheat GRX genes and their potential use as candidate genes for molecular breeding of stress-resistant wheat varieties.

Flexible green synthesis of 2-benzyl-3‑hydroxy-1H-pyrazolo([1,2-b]phthalazine and [1,2-a]pyridazine)‑dione derivatives using CuI@KSF nanocatalyst under solvent-free conditions

In the frame of research that examines the use of task CuI@KSF nanoparticles as an efficient catalyst, new 1H-pyrazolo[1,2-b]phthalazine-5,10‑dione (HPPhD) and 1H-pyrazolo[1,2-a]pyridazine-5,8‑dione (HPPyD) derivatives were prepared. Using the four-multicomponent condensation reaction (4MCRs) of phthalic anhydride, hydrazine monohydrate, aromatic aldehydes, and ethyl 3-oxo-3-phenylpropanoate under solvent free conditions at 80 °C. This method has several advantages, including, operational, simplicity, mild conditions, and maximum product yield. To monitor the progress of the reactions, new organic salty catalysts were used. New catalysts are cheap, benign, recyclable, and environmentally friendly. In addition, they are easy to prepare and use. They also showed good catalytic activity, which in conclusion led to the synthesis of new phthalazine derivatives with good to excellent yields. The new catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). To check the possible effect of these compounds in anticancer therapy, two types of proteins were selected and examined through docking calculations. In the case of 1DHT as an oxidoreductase enzyme compound 7e with the score of amount -8.99 represent the highest tendency toward interaction with the desired enzyme, while in the case of 6LQA by the dominance hydrophobic character, compound 7c seems likely to be more efficient.

Phenolic profile, antioxidant capacity and oxidoreductase enzyme activity in autochthonous grape varieties from Bosnia and Herzegovina

The variability of phenolic compounds among grape varieties has an important role in selecting winemaking techniques, but the use of phenolic profiles for quality control is still fragmented and incomplete. Given the recent climate change and global warming, biochemical characterisation of secondary metabolites in autochthonous grape varieties is a very important factor for their preservation and sustainable agriculture. Two autochthonous grape varieties from the western Herzegovina region in Bosnia and Herzegovina have been selected for the research targeting at the evaluation of their phenolic profiles, antioxidant activities, and the correlation with oxidoreductase enzymes polyphenol oxidase and Class III peroxidase, in different berry tissues. The obtained results indicate a similar qualitative profile of phenolic compounds in exocarp and mesocarp in both varieties, but their concentrations and antioxidant activity vary significantly. The correlation between phenolic compounds and oxidoreductase enzyme activities in different grape berry tissues is discussed in this article.

Insights into Molecular Mechanisms of Anticancer Activity of Juniperus communis Essential Oil in HeLa and HCT 116 Cells.

As cancer remains a significant global health challenge, there is an increasing need for novel therapeutic approaches. We investigated the antitumor potential of Juniperus communis berry essential oil on cervical cancer HeLa and colorectal HCT 116 cells. Cytotoxicity was evaluated through the MTT assay, revealing concentration-dependent reductions in cell viability. A clonogenic assay demonstrated long-term cytotoxic effects. Apoptosis markers were assessed via flow cytometric analysis and showed an induction of the intrinsic pathway in both cell lines, demonstrated by the elevated levels of cleaved caspase-3, Bax/Bcl-2 ratio, JC-10 monomer formation, and cytochrome C migration to the cytosol. The treatment inhibited cell-survival pathways in HCT 116 cells and arrested HeLa cells in the S phase. An extensive molecular docking screening provided insight into the binding affinity and interaction patterns of the essential oil components with NADH ubiquinone oxidoreductase and superoxide dismutase enzymes, further confirming the induction of the intrinsic pathway of apoptosis. The obtained in silico and in vitro results indicated the anticancer potential of J. communis berry essential oil as it interferes with cancer cell molecular mechanisms. Our findings highlight J. communis berry essential oil as a promising natural agent with anticancer potential.

Using Electroanalytical Techniques to Study Inhibition Mechanisms in Enzymes

Spectroscopic assays are typically utilized to study oxidoreductase enzyme kinetics, mechanisms, and inhibition. This talk will discuss the use of mediated and direct bioelectrocatalysis for studying kinetics followed by a thorough study of the effect of mediators in studying inhibition mechanisms. This will be followed up with strategies for studying mechanisms via direct bioelectrocatalysis. The talk will conclude with a discussion of the applications of these electroanalytical techniques in the fields of energy, sensing, and sustainable manufacturing.

OsLdh7, a rice lactate dehydrogenase, confers stress resilience in rice under cadmium stress through NAD+/NADH regulation

Lactate dehydrogenase (Ldh, EC 1.1.1.27), an oxidoreductase enzyme catalyses the interconversion of pyruvate to L-lactate and vice-versa with concomitant oxidation and reduction of NADH and NAD+. The enzyme functions as a ROS sensor and mitigates stress response by maintaining NAD+/NADH homeostasis. In this study, we delineated the role of the Ldh enzyme in imparting cadmium stress tolerance in rice. Previously, we identified a putatively active Ldh in rice (OsLdh7) through insilico modelling. Biochemical characterization of the OsLdh7 enzyme revealed it to be optimally active at pH 6.6 in the forward direction and pH 9 in the reverse direction. Overexpression of OsLdh7 in rice cv. IR64, increased tolerance of the transgenic lines to cadmium stress compared to the wild type (WT) at both seedling and reproductive stages. The transgenic lines showed increased enzyme activity in the reverse direction under cadmium stress, attributed to elevated cytosolic pH resulting from increased calcium concentration. This increased NADH content is highly essential for functioning of the ROS scavenging enzymes, RbohD and MPK6. qPCR analysis revealed that the overexpression lines had increased transcript abundance of these genes indicating an effective ROS scavenging mechanism. Additionally, the overexpression lines showed an efficient cadmium sequestration mechanism compared to the WT by increasing the transcript levels of the vacuolar transporters of cadmium as well as total phytochelatin content. Thus, our findings indicated OsLdh7 imparts cadmium stress tolerance in rice through a two-pronged approach by mitigating ROS and sequestering cadmium ions, highlighting its potential for crop improvement programs.

Optimization of Interfacial Properties Improved the Stability and Activity of the Catalase Enzyme Immobilized on Plastic Nanobeads.

The immobilization of catalase (CAT), a crucial oxidoreductase enzyme involved in quenching reactive oxygen species, on colloids and nanoparticles presents a promising strategy to improve dispersion and storage stability while maintaining its activity. Here, the immobilization of CAT onto polymeric nanoparticles (positively (AL) or negatively (SL) charged) was implemented directly (AL) or via surface functionalization (SL) with water-soluble chitosan derivatives (glycol chitosan (GC) and methyl glycol chitosan (MGC)). The interfacial properties were optimized to obtain highly stable AL-CAT, SL-GC-CAT, and SL-MGC-CAT dispersions, and confocal microscopy confirmed the presence of CAT in the composites. Assessment of hydrogen peroxide decomposition ability revealed that applying chitosan derivatives in the immobilization process not only enhanced colloidal stability but also augmented the activity and reusability of CAT. In particular, the use of MGC has led to significant advances, indicating its potential for industrial and biomedical applications. Overall, the findings highlight the advantages of using chitosan derivatives in CAT immobilization processes to maintain the stability and activity of the enzyme as well as provide important data for the development of processable enzyme-based nanoparticle systems to combat reactive oxygen species.

Persistence and pathway of glyphosate degradation in the coastal wetland soil of central Delaware

Glyphosate is a globally dominant herbicide. Here, we studied the degradation and microbial response to glyphosate application in a wetland soil in central Delaware for controlling invasive species (Phragmites australis). We applied a two-step solid-phase extraction method using molecularly imprinted polymers designed for the separation and enrichment of glyphosate and aminomethylphosphonic acid (AMPA) from soils before their analysis by ultra-high-performance liquid chromatography (UHPLC) and Q Exactive Orbitrap mass spectrometry methods. Our results showed that approximately 90 % of glyphosate degraded over 100 d after application, with AMPA being a minor (<10 %) product. Analysis of glyphosate-specific microbial genes to identify microbial response and function revealed that the expression of the phnJ gene, which codes C-P lyase enzyme, was consistently dominant over the gox gene, which codes glyphosate oxidoreductase enzyme, after glyphosate application. Both gene and concentration data independently suggested that C-P bond cleavage—which forms sarcosine or glycine—was the dominant degradation pathway. This is significant because AMPA, a more toxic product, is reported to be the preferred pathway of glyphosate degradation in other soil and natural environments. The degradation through a safer pathway is encouraging for minimizing the detrimental impacts of glyphosate on the environment.

Mechanistic insights into the conversion of flavin adenine dinucleotide (FAD) to 8-formyl FAD in formate oxidase: a combined experimental and in-silico study

Formate oxidase (FOx), which contains 8-formyl flavin adenine dinucleotide (FAD), exhibits a distinct advantage in utilizing ambient oxygen molecules for the oxidation of formic acid compared to other glucose-methanol-choline (GMC) oxidoreductase enzymes that contain only the standard FAD cofactor. The FOx-mediated conversion of FAD to 8-formyl FAD results in an approximate 10-fold increase in formate oxidase activity. However, the mechanistic details underlying the autocatalytic formation of 8-formyl FAD are still not well understood, which impedes further utilization of FOx. In this study, we employ molecular dynamics simulation, QM/MM umbrella sampling simulation, enzyme activity assay, site-directed mutagenesis, and spectroscopic analysis to elucidate the oxidation mechanism of FAD to 8-formyl FAD. Our results reveal that a catalytic water molecule, rather than any catalytic amino acids, serves as a general base to deprotonate the C8 methyl group on FAD, thus facilitating the formation of a quinone-methide tautomer intermediate. An oxygen molecule subsequently oxidizes this intermediate, resulting in a C8 methyl hydroperoxide anion that is protonated and dissociated to form OHC-RP and OH−. During the oxidation of FAD to 8-formyl FAD, the energy barrier for the rate-limiting step is calculated to be 22.8 kcal/mol, which corresponds to the required 14-hour transformation time observed experimentally. Further, the elucidated oxidation mechanism reveals that the autocatalytic formation of 8-formyl FAD depends on the proximal arginine and serine residues, R87 and S94, respectively. Enzymatic activity assay validates that the mutation of R87 to lysine reduces the kcat value to 75% of the wild-type, while the mutation to histidine results in a complete loss of activity. Similarly, the mutant S94I also leads to the deactivation of enzyme. This dependency arises because the nucleophilic OH− group and the quinone-methide tautomer intermediate are stabilized through the noncovalent interaction provided by R87 and S94. These findings not only explain the mechanistic details of each reaction step but also clarify the functional role of R87 and S94 during the oxidative maturation of 8-formyl FAD, thereby providing crucial theoretical support for the development of novel flavoenzymes with enhanced redox properties.

ДИНАМИКА АКТИВНОСТИ ФЕРМЕНТОВ УГЛЕРОДНОГО ЦИКЛА В УСЛОВИЯХ ПЕРЕХОДА НА МИНИМАЛЬНЫЕ ТЕХНОЛОГИИ ОБРАБОТКИ

The purpose of research is to study the dynamics of the activity of enzymes in the carbon cycle of agrochernozems and its effect on the transformation of easily mineralizable organic compounds when using waste and surface treatment methods. Field observations were carried out on the basis of the production experience of OOO OPH Dary Malinovki in the Sukhobuzimo District in the Krasnoyarsk forest-steppe (56°10′ N and 91°47′ E). The impact of dump and minimal processing technologies on the seaso¬nal dynamics of the activity of carbon cycle enzymes in the layers of agrochernozem is considered. The field experiment scheme is represented by the following options: moldboard plowing (standard), minimal tillage (surface disking), flat-cut tillage (cultivation). The level of polyphenol oxidase activity in the soil of the experimental variants was estimated to be weak. The intraseasonal dynamics of the studied enzymes was significant and correlated with the transformation of the humus accumulation coefficient. On non-dumping backgrounds, the variability of polyphenol oxidase was less variable. The minimum va¬lues of the humus accumulation coefficient were found at the initial stage of introducing the technologies under study during the fallow period of agrochernozems, as well as during the barley growing season. The maximum is in the soil under spring wheat crops. The use of flat-cut cultivators led to a strong relationship between the activity of polyphenol oxidase and the coefficient of humus accumulation. In the soil of all variants, an inverse relationship was observed between peroxidase activity and the coefficient of humus accumulation. The participation of peroxidase in the biochemical processes of mineralization was carried out mainly under the conditions of dump processing of agrochernozems. The activity of oxidoreductase enzymes indicated favorable conditions for the humification of organic compounds and the accumulation of newly formed humic substances in the soil when spring wheat was placed in fallow under conditions of using no-moldboard technologies.

Fluoromethylketone-Fragment Conjugates Designed as Covalent Modifiers of EcDsbA are Atypical Substrates.

Disulfide bond protein A (DsbA) is an oxidoreductase enzyme that catalyzes the formation of disulfide bonds in Gram-negative bacteria. In Escherichia coli, DsbA (EcDsbA) is essential for bacterial virulence, thus inhibitors have the potential to act as antivirulence agents. A fragment-based screen was conducted against EcDsbA and herein we describe the development of a series of compounds based on a phenylthiophene hit identified from the screen. A novel thiol reactive and "clickable" ethynylfluoromethylketone was designed for reaction with azide-functionalized fragments to enable rapid and versatile attachment to a range of fragments. The resulting fluoromethylketone conjugates showed selectivity for reaction with the active site thiol of EcDsbA, however unexpectedly, turnover of the covalent adduct was observed. A mechanism for this turnover was investigated and proposed which may have wider ramifications for covalent reactions with dithiol-disulfide oxidoreducatases.

Potential Involvement of MnCYP710A11 in Botrytis cinerea Resistance in Arabidopsis thaliana and Morus notabilis.

Cytochrome P450 (CYP) is a crucial oxidoreductase enzyme that plays a significant role in plant defense mechanisms. In this study, a specific cytochrome P450 gene (MnCYP710A11) was discovered in mulberry (Morus notabilis). Bioinformatic analysis and expression pattern analysis were conducted to elucidate the involvement of MnCYP710A11 in combating Botrytis cinerea infection. After the infection of B. cinerea, there was a notable increase in the expression of MnCYP710A11. MnCYP710A11 is overexpressed in Arabidopsis and mulberry and strongly reacts to B. cinerea. The overexpression of the MnCYP710A11 gene in Arabidopsis and mulberry led to a substantial enhancement in resistance against B. cinerea, elevated catalase (CAT) activity, increased proline content, and reduced malondialdehyde (MDA) levels. At the same time, H2O2 and O2- levels in MnCYP710A11 transgenic Arabidopsis were decreased, which reduced the damage of ROS accumulation to plants. Furthermore, our research indicates the potential involvement of MnCYP710A11 in B. cinerea resistance through the modulation of other resistance-related genes. These findings establish a crucial foundation for gaining deeper insights into the role of cytochrome P450 in mulberry plants.

Diversity and evolution of nitric oxide reduction in bacteria and archaea

Nitrous oxide is a potent greenhouse gas whose production is catalyzed by nitric oxide reductase (NOR) members of the heme-copper oxidoreductase (HCO) enzyme superfamily. We identified several previously uncharacterized HCO families, four of which (eNOR, sNOR, gNOR, and nNOR) appear to perform NO reduction. These families have novel active-site structures and several have conserved proton channels, suggesting that they might be able to couple NO reduction to energy conservation. We isolated and biochemically characterized a member of the eNOR family from the bacterium Rhodothermus marinus and found that it performs NO reduction. These recently identified NORs exhibited broad phylogenetic and environmental distributions, greatly expanding the diversity of microbes in nature capable of NO reduction. Phylogenetic analyses further demonstrated that NORs evolved multiple times independently from oxygen reductases, supporting the view that complete denitrification evolved after aerobic respiration.

The Ubiquinone-Ubiquinol Redox Cycle and Its Clinical Consequences: An Overview.

Coenzyme Q10 (CoQ10) plays a key role in many aspects of cellular metabolism. For CoQ10 to function normally, continual interconversion between its oxidised (ubiquinone) and reduced (ubiquinol) forms is required. Given the central importance of this ubiquinone-ubiquinol redox cycle, this article reviews what is currently known about this process and the implications for clinical practice. In mitochondria, ubiquinone is reduced to ubiquinol by Complex I or II, Complex III (the Q cycle) re-oxidises ubiquinol to ubiquinone, and extra-mitochondrial oxidoreductase enzymes participate in the ubiquinone-ubiquinol redox cycle. In clinical terms, the outcome of deficiencies in various components associated with the ubiquinone-ubiquinol redox cycle is reviewed, with a particular focus on the potential clinical benefits of CoQ10 and selenium co-supplementation.

Intermittent hydroxylamine dosing to strengthen stability of partial nitrification and nitrogen removal efficiency through continuous-flow anaerobic–aerobic-anoxic reactor treating municipal wastewater

Intermittent hydroxylamine (NH2OH) dosing strategy was applied to enhance the stability of partial nitrification and total nitrogen (N) removal efficiency (TNRE) in a continuous-flow process. The results showed 2 mg/L of NH2OH dosing (once every 6 h) could maintain stably partial nitrification with nitrite accumulation rate (NAR) of 91.6 % and TNRE of 92.6 %. The typical cycle suggested NH2OH dosing could promote simultaneous nitrification–denitrification (SND) and endogenous denitrification (END) while inhibit exogenous denitrification (EXD). Nitrification characteristics indicated the NH2OH dosing enhanced stability of partial nitrification by suppressing specific nitrite oxidation rate (SNOR), Nitrospira and nitrite oxidoreductase enzyme (Nxr). The microbial community suggested the aerobic denitrfiers, denitrifying glycogen accumulating organisms (DGAOs) and traditional denitrfiers were the potential contributor for advanced N removal. Moreover, NH2OH dosage was positively associated with NAR, SND and END. Overall, this study offers a feasible strategy to maintain sustainably partial nitrification that has great application potential.