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Journal of Inorganic Biochemistry Jul 2022Naturally-occurring variants of human cytochrome c (Cytc) that induce thrombocytopenia IV occur within Ω-loop C (residues 40-57). These variants enhance the peroxidase...
Naturally-occurring variants of human cytochrome c (Cytc) that induce thrombocytopenia IV occur within Ω-loop C (residues 40-57). These variants enhance the peroxidase activity of human Cytc apparently by facilitating access to the heme by destabilizing Ω-loops C and D (residues 70-85). Given the importance of peroxidase activity in the early stages of apoptosis, we identified three sites with the EVmutation algorithm in or near Ω-loop C that coevolve and differ between yeast iso-1-Cytc and human Cytc. We prepared iso-1-Cytc variants with all possible combinations of the S40T, V57I and N63T substitutions to determine if these residues decrease the peroxidase activity of iso-1-Cytc to that of human Cytc producing an effective off state for a peroxidase signaling switch. At pH 6 and above, all variants significantly decreased peroxidase activity. However, the correlation of peroxidase activity with local and global stability, expected if cooperative unfolding of Ω-loops C and D is required for peroxidase activity, was generally poor. The m-values derived from the guanidine hydrochloride dependence of the kinetics of imidazole binding to horse Cytc, which is well-characterized by native-state hydrogen exchange methods, and K72A/K73A/K79A iso-1-Cytc show that local structural fluctuations and not subglobal cooperative unfolding of Ω-loops C and D are sufficient to permit binding of a small molecule like peroxide to the heme. A 2.46 Å structure of N63T iso-1-Cytc identifies a change to a hydrogen bond network linking Ω-loops C and D that could modulate the local fluctuations needed for the intrinsic peroxidase activity of Cytc.
Topics: Animals; Cytochromes c; Heme; Horses; Humans; Hydrogen-Ion Concentration; Peroxidase; Peroxidases; Protein Conformation; Saccharomyces cerevisiae
PubMed: 35428021
DOI: 10.1016/j.jinorgbio.2022.111819 -
Analytica Chimica Acta Mar 2022The development of functional nanomaterials based on the unique structure and morphology of MXene for biosensing has aroused great interest. In this work, using thiourea...
The development of functional nanomaterials based on the unique structure and morphology of MXene for biosensing has aroused great interest. In this work, using thiourea as the doping source, a new structure composed of nitrogen and sulfur co-doped on the surface of TiC nanosheets was synthesized through a simple one-step synthesis method. Fortunately, the obtained nitrogen and sulfur co-doped TiC nanosheets (NS-TiC NSs) showed excellent peroxidase-like activity and electrochemical activity. The catalytic mechanism of modified TiC nanosheets was explored. It is revealed that the catalytic mechanism of NS-TiC NSs is composed of two important parts: the dissociation and adsorption of HO and the protonation of TMB. In addition, the fabricated NS-TiC NSs-based electrochemical biosensor is superior to the counterpart from TiC nanosheets, indicating that the doping of nitrogen and sulfur elements provides more active sites and promotes electron transport efficiency. Combining the unique advantages of colorimetry and electrochemical technology, we have developed a fast, accurate, intuitive and efficient UA detection method for uric acid in the range of 2 μM-400 μM with a detection limit (LOD) of 0.19 μM. The established sensing platform in this study prove the possibility of the doping method for the development of MXene-based biosensors with high sensitivity and high performance, and pave the way for the future development of biosensors for biomedical fields.
Topics: Biosensing Techniques; Hydrogen Peroxide; Nitrogen; Peroxidase; Peroxidases; Sulfur; Titanium; Uric Acid
PubMed: 35168720
DOI: 10.1016/j.aca.2022.339520 -
Advanced Materials (Deerfield Beach,... Apr 2022MetalN-coordinated centers supported by carbonaceous substrates have emerged as promising artificial metalloenzymes (AMEs) to mimic the biocatalytic effects of their...
MetalN-coordinated centers supported by carbonaceous substrates have emerged as promising artificial metalloenzymes (AMEs) to mimic the biocatalytic effects of their natural counterparts. However, the synthesis of well-defined AMEs that contain different atomic metalN centers but present similar physicochemical and coordination structures remains a substantial challenge. Here, 20 different types of AMEs with similar geometries and well-defined atomic metalN-coordinated centers are synthesized to compare and disclose the catalytic activities, substrate selectivities, kinetics, and reactive oxygen species (ROS) products. Their oxidase (OXD)-, peroxidase (POD)-, and halogen peroxidase (HPO)-mimetic catalytic behaviors are systematically explored. The Fe-AME shows the highest OXD- and HPO-mimetic activities compared to the other AMEs due to its high v (0.927 × 10 m s ) and low K (1.070 × 10 m), while the Cu-AME displays the best POD-like performance. Furthermore, theoretical calculation reveals that the ROS-catalytic paths and activities are highly related to the electronic structures of the metal centers. Benefiting from its facile adsorption of H O molecule and lower energy barrier to generating •O , the Fe-AME displays higher ROS-catalytic performances than the Mn-AME. The engineered AMEs show not only remarkably high ROS-catalytic performances but also provide new guidance toward developing metalN-coordinated biocatalysts for broad application fields.
Topics: Catalysis; Metalloproteins; Metals; Oxidoreductases; Peroxidase; Peroxidases; Reactive Oxygen Species
PubMed: 35132711
DOI: 10.1002/adma.202200255 -
Biosensors Dec 2023The accurate and simultaneous detection of neurotransmitters, such as dopamine (DA) and epinephrine (EP), is of paramount importance in clinical diagnostic fields....
The accurate and simultaneous detection of neurotransmitters, such as dopamine (DA) and epinephrine (EP), is of paramount importance in clinical diagnostic fields. Herein, we developed cerium-molybdenum disulfide nanoflowers (Ce-MoS NFs) using a simple one-pot hydrothermal method and demonstrated that they are highly conductive and exhibit significant peroxidase-mimicking activity, which was applied for the simultaneous electrochemical detection of DA and EP. Ce-MoS NFs showed a unique structure, comprising MoS NFs with divalent Ce ions. This structural design imparted a significantly enlarged surface area of 220.5 m g with abundant active sites as well as enhanced redox properties, facilitating electron transfer and peroxidase-like catalytic action compared with bare MoS NFs without Ce incorporation. Based on these beneficial features, Ce-MoS NFs were incorporated onto a screen-printed electrode (Ce-MoS NFs/SPE), enabling the electrochemical detection of HO based on their peroxidase-like activity. Ce-MoS NFs/SPE biosensors also showed distinct electrocatalytic oxidation characteristics for DA and EP, consequently yielding the highly selective, sensitive, and simultaneous detection of target DA and EP. Dynamic linear ranges for both DA and EP were determined to be 0.05~100 μM, with detection limits (S/N = 3) of 28 nM and 44 nM, respectively. This study shows the potential of hierarchically structured Ce-incorporated MoS NFs to enhance the detection performances of electrochemical biosensors, thus enabling extensive applications in healthcare, diagnostics, and environmental monitoring.
Topics: Peroxidase; Dopamine; Molybdenum; Hydrogen Peroxide; Peroxidases; Epinephrine; Electrochemical Techniques
PubMed: 38131775
DOI: 10.3390/bios13121015 -
Food Chemistry Sep 2022In using a flow-injection recirculating-catalysis system developed by us to research the simultaneous quantification for peroxidase and ascorbate, it was discovered that...
In using a flow-injection recirculating-catalysis system developed by us to research the simultaneous quantification for peroxidase and ascorbate, it was discovered that the concentrations of peroxidase activity and ascorbate are correlative with the slope and the negative intercept of the linear response curve during a peroxidase-catalyzed kinetic course. Therefore, based on this finding, a new analytical method and a simplified equation for quantifying the peroxidase activity concentration were proposed, Then, test conditions were optimized, finally the use of the method has realized the simultaneous determination for peroxidase of 2-40 U/L and ascorbate of 0.4-12 mg/L in various vegetables (60 μL). The assayed results were consistent with the comparison method, in which the repeatability (RSD < 1.43%, n = 11) was satisfactory. Another important conclusion obtained in this study is that the determination of the peroxidase activity in biosamples must use the kinetic curve method for fear of the influence from the ascorbate's lag phase.
Topics: Antioxidants; Ascorbate Peroxidases; Ascorbic Acid; Catalysis; Coloring Agents; Peroxidase; Peroxidases; Vegetables
PubMed: 35483291
DOI: 10.1016/j.foodchem.2022.133053 -
Small (Weinheim An Der Bergstrasse,... May 2023Nanozymes are nanomaterials with biocatalytic properties under physiological conditions and are one class of artificial enzymes to overcome the high cost and low...
Nanozymes are nanomaterials with biocatalytic properties under physiological conditions and are one class of artificial enzymes to overcome the high cost and low stability of natural enzymes. However, surface ligands on nanomaterials will decrease the catalytic activity of the nanozymes by blocking the active sites. To address this limitation, ligand-free PtAg nanoclusters (NCs) are synthesized and applied as nanozymes for various enzyme-mimicking reactions. By taking advantage of the mutual interaction of zeolitic imidazolate frameworks (ZIF-8) and Pt precursors, a good dispersion of PtAg bimetal NCs with a diameter of 1.78 ± 0.1 nm is achieved with ZIF-8 as a template. The incorporation of PtAgNCs in the voids of ZIF-8 is confirmed with structural analysis using the atomic pair-distribution function and powder X-ray diffraction. Importantly, the PtAgNCs present good catalytic activity for various enzyme-mimicking reactions, including peroxidase-/catalase- and oxidase-like reactions. Further, this work compares the catalytic activity between PtAg NCs and PtAg nanoparticles with different compositions and finds that these two nanozymes present a converse dependency of Ag-loading on their activity. This study contributes to the field of nanozymes and presents a potential option to prepare ligand-free bimetal biocatalysts with sizes in the nanocluster regime.
Topics: Peroxidase; Molecular Mimicry; Metal Nanoparticles; Platinum; Silver; Alloys
PubMed: 36755199
DOI: 10.1002/smll.202206772 -
Journal of Materials Chemistry. B Dec 2023Morpheeins are proteins that adapt their morphology and function to the environment. Therefore, their use in nanotechnology opens up the bottom-up preparation of...
Morpheeins are proteins that adapt their morphology and function to the environment. Therefore, their use in nanotechnology opens up the bottom-up preparation of anisotropic metamaterials, based on the sequential use of different stimuli. A prominent member of this family of proteins is peroxiredoxins (Prx), with dual peroxidase and chaperone function, depending on the pH of the media. At high pH, they show a toroidal morphology that turns into tubular stacks upon acidification. While the toroidal conformers have been explored as building blocks to yield 1D and 2D structures, the obtention of higher ordered materials remain unexplored. In this research, the morpheein behaviour of Prx is exploited to yield columnar aggregates, that are subsequently self-assembled into 3D anisotropic bundles. This is achieved by electrostatic recognition between the negatively charged protein rim and a positively charged porphyrin acting as molecular glue. The subsequent and orthogonal input lead to the alignment of the monodimensional stacks side-by-side, leading to the precise assembly of this anisotropic materials.
Topics: Peroxiredoxins; Static Electricity; Peroxidase; Nanotechnology; Hydrogen-Ion Concentration
PubMed: 37990925
DOI: 10.1039/d3tb00369h -
Food Chemistry Jul 2024Metal oxide nanozymes are emerging as promising materials for food safety detection, offering several advantages over natural enzymes, including superior stability,... (Review)
Review
Metal oxide nanozymes are emerging as promising materials for food safety detection, offering several advantages over natural enzymes, including superior stability, cost-effectiveness, large-scale production capability, customisable functionality, design options, and ease of modification. Optical biosensors based on metal oxide nanozymes have significantly accelerated the advancement of analytical research, facilitating the rapid, effortless, efficient, and precise detection and characterisation of contaminants in food. However, few reviews have focused on the application of optical biosensors based on metal oxide nanozymes for food safety detection. In this review, the catalytic mechanisms of the catalase, oxidase, peroxidase, and superoxide dismutase activities of metal oxide nanozymes are characterized. Research developments in optical biosensors based on metal oxide nanozymes, including colorimetric, fluorescent, chemiluminescent, and surface-enhanced Raman scattering biosensors, are comprehensively summarized. The application of metal oxide nanozyme-based biosensors for the detection of nitrites, sulphites, metal ions, pesticides, antibiotics, antioxidants, foodborne pathogens, toxins, and other food contaminants has been highlighted. Furthermore, the challenges and future development prospects of metal oxide nanozymes for sensing applications are discussed. This review offers insights and inspiration for further investigations on optical biosensors based on metal oxide nanozymes for food safety detection.
Topics: Food Safety; Pesticides; Peroxidase; Peroxidases; Anti-Bacterial Agents; Catalysis; Coloring Agents; Nanostructures; Biosensing Techniques
PubMed: 38520903
DOI: 10.1016/j.foodchem.2024.139019 -
Advanced Healthcare Materials Nov 2023Magnetite-based nanozymes have attracted great interest for catalytic cancer therapy enabled by catalyzing hydrogen peroxide (H O ) to produce highly toxic hydroxyl...
Magnetite-based nanozymes have attracted great interest for catalytic cancer therapy enabled by catalyzing hydrogen peroxide (H O ) to produce highly toxic hydroxyl radicals (•OH) to kill tumor cells. However, their therapeutic efficacies remain low due to insufficient •OH. Here, a light-responsive carbon-encapsulated magnetite nanodoughnuts (CEMNDs) with dual-catalytic activities for photothermal-enhanced chemodynamic therapy (CDT) is reported. The CEMNDs can accumulate in tumor and get into tumor cells and effectively act as peroxidase to convert H O to •OH that causes tumor cell death. The CEMNDs also possess intrinsic glutathione oxidase-like activity that which catalyzes the oxidation of reduced glutathione and produce lipid peroxidase for enhanced catalytic therapy. Furthermore, the CEMNDs can absorb 1064 nm light to elevate local temperature and increase release of Fe ions for photothermal therapy and enhanced CDT respectively. The in vivo experiments in an aggressive and drug-resistant metastatic mouse model of triple negative breast cancer model demonstrate excellent synergistic anti-tumor function and no measurable systemic toxicity of CEMNDs.
Topics: Animals; Mice; Ferrosoferric Oxide; Photothermal Therapy; Peroxidase; Peroxidases; Carbon; Hydrogen Peroxide; Cell Line, Tumor; Neoplasms; Tumor Microenvironment; Glutathione
PubMed: 37552521
DOI: 10.1002/adhm.202301926 -
Genes Aug 2023Although thaumatin-like proteins () are involved in resistance to a variety of fungal diseases, whether the 5 and 6 genes in tomato plants () confer resistance to the...
Although thaumatin-like proteins () are involved in resistance to a variety of fungal diseases, whether the 5 and 6 genes in tomato plants () confer resistance to the pathogenesis of soil-borne diseases has not been demonstrated. In this study, five soil-borne diseases (fungal pathogens: , , and ; bacterial pathogens: subsp. and ) were used to infect susceptible "No. 5" and disease-resistant "S-55" tomato cultivars. We found that and transcript levels were higher in susceptible cultivars treated with the three fungal pathogens than in those treated with the two bacterial pathogens and that transcript levels varied depending on the pathogen. Moreover, the and transcript levels were much higher in disease-resistant cultivars than in disease-susceptible cultivars, and the and transcript levels were higher in cultivars treated with the same fungal pathogen than in those treated with bacterial pathogens. transcript levels were higher than . and overexpression and gene-edited transgenic mutants were generated in both susceptible and resistant cultivars. Overexpression and knockout increased and decreased resistance to the five diseases, respectively. Transgenic plants overexpressing and inhibited the activities of peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) after inoculation with fungal pathogens, and the activities of POD, SOD, and APX were similar to those of fungi after infection with bacterial pathogens. The activities of CAT were increased, and the activity of β-1,3-glucanase was increased in both the fungal and bacterial treatments. Overexpressed plants were more resistant than the control plants. After and knockout plants were inoculated, POD, SOD, and APX had no significant changes, but CAT activity increased and decreased significantly after the fungal and bacterial treatments, contrary to overexpression. The activity of β-1,3-glucanase decreased in the treatment of the five pathogens, and the knocked-out plants were more susceptible to disease than the control. In summary, this study contributes to the further understanding of disease resistance mechanisms in tomato plants.
Topics: Solanum lycopersicum; Peroxidase; Superoxide Dismutase; Peroxidases; Ascorbate Peroxidases
PubMed: 37628673
DOI: 10.3390/genes14081622