Mykhailo Gonchar - Academia.edu (original) (raw)

Papers by Mykhailo Gonchar

Biotechnologia Acta, 2011

Таблиця 3. Активність амінотрансфераз у плазмі крові, мкмоль/л на год (M ± m, n = 3) Група тварин... more Таблиця 3. Активність амінотрансфераз у плазмі крові, мкмоль/л на год (M ± m, n = 3) Група тварин За 5 діб до відлучення Доба після відлучення 3 тя 10 та 20 та 30 та Аланінамінотрансфераза Контрольна 0

Chemical Physics Letters, 2009

Surface plasmon resonance (SPR) and subsequent surface-enhanced Raman scattering (SERS) of gold n... more Surface plasmon resonance (SPR) and subsequent surface-enhanced Raman scattering (SERS) of gold nanoaggregates were investigated with reference to hot-sites availability. Correlated SPR and SERS observation of the same sample shows that the plasmon excitations ...

Letters in Applied Microbiology, Feb 16, 2016

Significance and Impact of the Study: Thermotolerant microbial strains are required in various in... more Significance and Impact of the Study: Thermotolerant microbial strains are required in various industrial applications, for improving productivity and for decreasing the risk of undesirable contaminations when higher temperatures are used. It is important to search for such strains in extreme environments or exotic niches. In this paper, new thermotolerant strains were identified belonging to the Saccharomyces cerevisiae, but differed from typical bakers' yeast, essentially by their growth rate at higher temperature. The described yeast strains are promising for using in biotechnological industry, especially, for production of ethanol and other products at higher temperatures.

Vìsnik Lʹvìvsʹkogo unìversitetu, Jan 28, 2020

Sensors and Actuators B-chemical, Oct 1, 2023

Biotechnologia Acta, 2008

Yeast, Dec 21, 2018

During the recent decades, a lot of data about the significance of D-lactate determination in foo... more During the recent decades, a lot of data about the significance of D-lactate determination in food technology and quality control has been accumulated. Nowadays, the development of new methods for the determination of D-lactate is very relevant, especially with regards to biosensors. To construct a D-lactate-selective biosensor, we suggest using the mitochondria of recombinant yeast cells of Ogataea (Hansenula) polymorpha "tr6" (gcr1 catX/Δcyb2, prAOX_DLDH) overproducing D-lactate: cytochrome c-oxidoreductase (DLDH, EC 1.1.2.4) and lacking an L-lactate-specific enzyme (flavocytochrome b 2 , E.C. 1.1.2.3). The usage of the pure enzyme is problematic due to the complexity of its isolation and stabilization because of the intramembranous localization of DLDH. The enzyme catalyzes D-lactate oxidation to pyruvate coupled with ferricytochrome c reduction to ferrocytochrome c. The constructed biosensor is characterized by high sensitivity (18.5 А•М-1 •m-2), a low detection limit (3 µM of D-lactate), wide linear ranges, good selectivity and sufficient stability. The real samples analysis of D-lactate in dairy products was performed, and high correlation of the obtained results with the reference approach (0.7 < r < 1) and literature data was demonstrated.

Archives of Metallurgy and Materials, Sep 1, 2015

GOLD NANOPARTICLES LIKE A MATRIX FOR COVALENT IMMOBILIZATION OF CHOLESTEROL OXIDASE-APPLICATION F... more GOLD NANOPARTICLES LIKE A MATRIX FOR COVALENT IMMOBILIZATION OF CHOLESTEROL OXIDASE-APPLICATION FOR BIOSENSING NANOCZĄSTKI ZŁOTA JAKO MATRYCA DO IMMOBILIZACJI OKSYDAZY CHOLESTEROLU-ZASTOSOWANIE W BIOSENSORACH Gold nanoparticles are emerging as promising agents for various areas of material science as well as nanotechnology, electronics and medicine. The interest in this material is provided due to its unique optical, electronic and molecular-recognition properties. This paper presents results of preparation, characterization and biofunctionalization of gold nanoparticles. Nanoparticles have been conjugated with the cholesterol oxidase enzyme in order to prepare the active element for biosensors. Cholesterol oxidase is one of the most important analytical enzyme, used for cholesterol assay in clinical diagnostics, and there is still a necessity in improvement of existing analytical techniques, including bio-nanotechnological approaches based on modern nanosystems. The prepared bio-nanosystem was characterized by the enzyme activity test. Obtained results showed a stable binding of the enzyme with nanoparticles and preserved the bioactivity approves which gives possibility to use the prepared bio-nanosystems for analytical purposes. The Surface Plazmon Resonance and the Surface Enhanced Raman Scattering as specific for nanocurriers effects were observed what enable us to research the oscillation spectra of enzyme. These spectra were compared with ones obtained by IR-spectroscopy. The vibrational lines are attributed to chemical functional groups existing in enzyme, for example, amino acids, amide groups as well as flavin-adenine dinucleotide cholesterol oxidase prosthetic group. By this way the identified spectral lines can be used as a distinguishing mark of enzyme.

Materials, May 6, 2017

Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde anal... more Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in the chemosensor's selectivity for the target analyte. The sensitivity of the best chemosensor prototype to formaldehyde is uniquely high (28180 A•M −1 •m −2) with a detection limit of 0.05 mM. The chemosensor remained stable over a one-year storage period. The formaldehye-selective chemosensor was tested on samples of commercial preparations. A high correlation was demonstrated between the results obtained by the proposed chemosensor, chemical and enzymatic methods (R = 0.998). The developed formaldehyde-selective amperometric chemosensor is very promising for use in industry and research, as well as for environmental control.

Biotechnologia Acta, 2014

Biotechnologia Acta, 2008

Springer eBooks, 2021

Flavocytochrome b2 (EC 1.1.2.3; L-lactate cytochrome: c oxidoreductase, FC b2) from the thermotol... more Flavocytochrome b2 (EC 1.1.2.3; L-lactate cytochrome: c oxidoreductase, FC b2) from the thermotolerant methylotrophic yeast Ogataea polymorpha is a thermostable enzyme-prospective for a highly selective L-lactate analysis in the medicine, nutrition sector, and quality control of commercial products. Here we describe the construction of FC b2 producers by overexpression of the CYB2 gene O. polymorpha, encoding FC b2, under the control of a strong alcohol oxidase promoter in the frame of plasmid for multicopy integration with the next transformation of recipient strain O. polymorpha C-105 (gcr1 catX) impaired in the glucose repression and devoid of catalase activity. The selected recombinant strain O. polymorpha "tr1" (gcr1 catX CYB2), characterized by eightfold increased FC b2 activity compared to the initial strain, was used as a source of the enzyme. For purification of FC b2 a new method of affinity chromatography was developed and purified preparations of the enzyme were used for the construction of the highly selective enzymatic kits and amperometric biosensor for L-lactate analysis in human liquids and foods.

Analytica Chimica Acta, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Biosensors - Emerging Materials and Applications, 2011

Biosensors-Emerging Materials and Applications 402 interfering substances into a sensitive biosel... more Biosensors-Emerging Materials and Applications 402 interfering substances into a sensitive bioselective layer and the transducer surface, or creates a diffusion barrier for the analyte. Such membrane structures increase the stability of the biorecognition element, enhance its selectivity and provide the diffusion limitations for biochemical reactions. Electrochemical, optical, piezoelectric, thermoelectric, transistor, acoustic and other elements are used as transducers in biosensor systems. Electrochemical (amperometric, potentiometric, conductometric) and optical (surface plasmon resonance) devices are the most exploited transducers in commercially available biosensors (Commercial Biosensors, 1998). Basically, biosensors can be regarded as information transducers in which the energy of biospecific interactions is transformed into information about the nature and concentration of an analyte in the sample. The most essential advantages of biosensors are excellent chemical selectivity and high sensitivity, possibility of miniaturization and compatibility with computers. Their drawbacks are limited stability and a rather complicated procedure for preparation of the biologically active material. Enzyme biosensors are the most widespread devices (Zhao & Jiang, 2010); many of them are produced commercially. Enzyme biosensors are characterized by their high selectivity. They also provide fast output due to high activity and high local enzyme concentration in a sensitive layer. The drawbacks of enzyme biosensors are insufficient stability and the high price of purified enzymes. Cell sensors, especially microbial ones, have been actively developed only in recent years (Shimomura-Shimizu & Karube, 2010a, 2010b; Su et al., 2011). Cell biosensors have a range of considerable advantages when compared to their enzyme analogues: availability of cells, low price and simple procedure of cell isolation, possibility to use long metabolic chains, avoiding purification of enzymes and coenzymes, advanced opportunity for metabolic engineering, integrity of the cell response (important in assaying total toxicity and mutagenic action of environmental pollutants), possibility to retain viability of sensoring cells and even to provide their propagation, and, in some cases, higher stability of cell elements compared to enzyme ones. The main drawbacks of microbial biosensors are a rather low signal rate due to a lower concentration of enzymes involved in cellular response, as well as low selectivity of cell output (e.g. in the case of microbial O 2 electrode sensors due to a broad substrate specificity of cellular respiration). These drawbacks are not absolute, taking into account recent progress in genetic engineering and the possibility to over-express the key analytical enzyme in the cell (Gonchar et al., 2002). Most biosensors have been created for clinical diagnostics (D'Orazio, 2003; Song et al., 2006; Belluzo et al., 2008). They exploit enzymes as biocatalytic recognition elements and immunoreagents and DNA fragments as affinity tools for biorecognition of the target analytes (metabolites, antigens, antibodies, nucleic acids) coupled to electrochemical and optical modes of transduction. For simultaneous detection of multiple analytes, microarray techniques are developed for automated clinical diagnostics (Seidel & Niessner, 2008). For continuous monitoring of living processes, reagentless implantable biosensors have been developed (Wilson & Ammam, 2007). Biosensors are regarded as very promising tools for clinical cancer testing (Rasooly & Jacobson, 2006; Wang, 2006). New genomic and proteomic approaches are being used for revealing cancer biomarkers related with genetic features, changes in gene expression, protein profiles and post-translational modifications of proteins. Recent progress in nanobiotechnology allows using nanomolecular approaches for clinical diagnostic procedures (Salata, 2004; Jain, 2007). The most important applications are www.intechopen.com

Environmental Biotechnology, 1995

An enzyme-mediated reaction was proposed for the photometric assay of formaldehyde by using alcoh... more An enzyme-mediated reaction was proposed for the photometric assay of formaldehyde by using alcohol oxidase, peroxidase and effective chromogenic substrate. This method was shown to be rather sensitive but not specific (methanol and ethanol also give a positive reaction).

Science and innovation, 2017

For the time, no screening test kits for L-arginine monitoring in biological fluids, including th... more For the time, no screening test kits for L-arginine monitoring in biological fluids, including the blood, have been available in the arsenal of domestic clinical diagnostics. The Argitest enzymatic kit is based on the enzymatic-chemical method of L-arginine quantitative analysis developed using different forms of recombinant human liver arginase I (arginase) and arginine deiminase. The method is highly selective, cheap, simple, and fast. It is remarkable for stability of enzymes and final products. The article demonstrates the possibility of using recombinant arginine-selective enzymes in composition of Argitest kit. The catalytic and analytic characteristics of these enzymes have been studied. It has been shown that each enzyme can be used as a component of enzymatic kit.

RSC Advances

Novel Zn/Cd/Cubd nanozymes possesses the ability to mimic coenzyme-dependent selenite reductase. ... more Novel Zn/Cd/Cubd nanozymes possesses the ability to mimic coenzyme-dependent selenite reductase. A new amperometric biosensor for determination of selenite was constructed.

RSC Advances

Novel colorimetric method based on alginate beads encapsulated with nPtCu and alcohol oxidase hav... more Novel colorimetric method based on alginate beads encapsulated with nPtCu and alcohol oxidase have been developed and optimized.

Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies

Nanozymes, which have high enzyme-like activity of natural enzymes, are very promising for analyt... more Nanozymes, which have high enzyme-like activity of natural enzymes, are very promising for analytical purposes, in particular, for the development of methods for sensitive, quantitative detection of practically important analytes – biomarkers of common diseases or pharmaceutical products. Recently, it has been reported that artificial enzymes with laccase-like activity or “nanolaccases (nLacs),” can serve as catalytic elements for the creation of sensitive methods for catecholamines. Our work aimed to obtain laccase-like nanozymes and characterize and demonstrate their suitability for spectrophotometric adrenaline (AD) analysis. In this article, we report on preparing five hexacyanoferrate nanoparticles (HCF NPs) that possess laccase-like activity, particularly, Co-HCF, Ni-HCF, Mn-HCF, Zn-HCF, and Cu-HCF. Among the investigated nLacs, Cu-HCF was selected and characterized. It was shown that Cu-HCF reveals the highest activities, is stable in various pH conditions in the range 3.0–6....

Biotechnologia Acta, 2011

Таблиця 3. Активність амінотрансфераз у плазмі крові, мкмоль/л на год (M ± m, n = 3) Група тварин... more Таблиця 3. Активність амінотрансфераз у плазмі крові, мкмоль/л на год (M ± m, n = 3) Група тварин За 5 діб до відлучення Доба після відлучення 3 тя 10 та 20 та 30 та Аланінамінотрансфераза Контрольна 0

Chemical Physics Letters, 2009

Surface plasmon resonance (SPR) and subsequent surface-enhanced Raman scattering (SERS) of gold n... more Surface plasmon resonance (SPR) and subsequent surface-enhanced Raman scattering (SERS) of gold nanoaggregates were investigated with reference to hot-sites availability. Correlated SPR and SERS observation of the same sample shows that the plasmon excitations ...

Letters in Applied Microbiology, Feb 16, 2016

Significance and Impact of the Study: Thermotolerant microbial strains are required in various in... more Significance and Impact of the Study: Thermotolerant microbial strains are required in various industrial applications, for improving productivity and for decreasing the risk of undesirable contaminations when higher temperatures are used. It is important to search for such strains in extreme environments or exotic niches. In this paper, new thermotolerant strains were identified belonging to the Saccharomyces cerevisiae, but differed from typical bakers' yeast, essentially by their growth rate at higher temperature. The described yeast strains are promising for using in biotechnological industry, especially, for production of ethanol and other products at higher temperatures.

Vìsnik Lʹvìvsʹkogo unìversitetu, Jan 28, 2020

Sensors and Actuators B-chemical, Oct 1, 2023

Biotechnologia Acta, 2008

Yeast, Dec 21, 2018

During the recent decades, a lot of data about the significance of D-lactate determination in foo... more During the recent decades, a lot of data about the significance of D-lactate determination in food technology and quality control has been accumulated. Nowadays, the development of new methods for the determination of D-lactate is very relevant, especially with regards to biosensors. To construct a D-lactate-selective biosensor, we suggest using the mitochondria of recombinant yeast cells of Ogataea (Hansenula) polymorpha "tr6" (gcr1 catX/Δcyb2, prAOX_DLDH) overproducing D-lactate: cytochrome c-oxidoreductase (DLDH, EC 1.1.2.4) and lacking an L-lactate-specific enzyme (flavocytochrome b 2 , E.C. 1.1.2.3). The usage of the pure enzyme is problematic due to the complexity of its isolation and stabilization because of the intramembranous localization of DLDH. The enzyme catalyzes D-lactate oxidation to pyruvate coupled with ferricytochrome c reduction to ferrocytochrome c. The constructed biosensor is characterized by high sensitivity (18.5 А•М-1 •m-2), a low detection limit (3 µM of D-lactate), wide linear ranges, good selectivity and sufficient stability. The real samples analysis of D-lactate in dairy products was performed, and high correlation of the obtained results with the reference approach (0.7 < r < 1) and literature data was demonstrated.

Archives of Metallurgy and Materials, Sep 1, 2015

GOLD NANOPARTICLES LIKE A MATRIX FOR COVALENT IMMOBILIZATION OF CHOLESTEROL OXIDASE-APPLICATION F... more GOLD NANOPARTICLES LIKE A MATRIX FOR COVALENT IMMOBILIZATION OF CHOLESTEROL OXIDASE-APPLICATION FOR BIOSENSING NANOCZĄSTKI ZŁOTA JAKO MATRYCA DO IMMOBILIZACJI OKSYDAZY CHOLESTEROLU-ZASTOSOWANIE W BIOSENSORACH Gold nanoparticles are emerging as promising agents for various areas of material science as well as nanotechnology, electronics and medicine. The interest in this material is provided due to its unique optical, electronic and molecular-recognition properties. This paper presents results of preparation, characterization and biofunctionalization of gold nanoparticles. Nanoparticles have been conjugated with the cholesterol oxidase enzyme in order to prepare the active element for biosensors. Cholesterol oxidase is one of the most important analytical enzyme, used for cholesterol assay in clinical diagnostics, and there is still a necessity in improvement of existing analytical techniques, including bio-nanotechnological approaches based on modern nanosystems. The prepared bio-nanosystem was characterized by the enzyme activity test. Obtained results showed a stable binding of the enzyme with nanoparticles and preserved the bioactivity approves which gives possibility to use the prepared bio-nanosystems for analytical purposes. The Surface Plazmon Resonance and the Surface Enhanced Raman Scattering as specific for nanocurriers effects were observed what enable us to research the oscillation spectra of enzyme. These spectra were compared with ones obtained by IR-spectroscopy. The vibrational lines are attributed to chemical functional groups existing in enzyme, for example, amino acids, amide groups as well as flavin-adenine dinucleotide cholesterol oxidase prosthetic group. By this way the identified spectral lines can be used as a distinguishing mark of enzyme.

Materials, May 6, 2017

Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde anal... more Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in the chemosensor's selectivity for the target analyte. The sensitivity of the best chemosensor prototype to formaldehyde is uniquely high (28180 A•M −1 •m −2) with a detection limit of 0.05 mM. The chemosensor remained stable over a one-year storage period. The formaldehye-selective chemosensor was tested on samples of commercial preparations. A high correlation was demonstrated between the results obtained by the proposed chemosensor, chemical and enzymatic methods (R = 0.998). The developed formaldehyde-selective amperometric chemosensor is very promising for use in industry and research, as well as for environmental control.

Biotechnologia Acta, 2014

Biotechnologia Acta, 2008

Springer eBooks, 2021

Flavocytochrome b2 (EC 1.1.2.3; L-lactate cytochrome: c oxidoreductase, FC b2) from the thermotol... more Flavocytochrome b2 (EC 1.1.2.3; L-lactate cytochrome: c oxidoreductase, FC b2) from the thermotolerant methylotrophic yeast Ogataea polymorpha is a thermostable enzyme-prospective for a highly selective L-lactate analysis in the medicine, nutrition sector, and quality control of commercial products. Here we describe the construction of FC b2 producers by overexpression of the CYB2 gene O. polymorpha, encoding FC b2, under the control of a strong alcohol oxidase promoter in the frame of plasmid for multicopy integration with the next transformation of recipient strain O. polymorpha C-105 (gcr1 catX) impaired in the glucose repression and devoid of catalase activity. The selected recombinant strain O. polymorpha "tr1" (gcr1 catX CYB2), characterized by eightfold increased FC b2 activity compared to the initial strain, was used as a source of the enzyme. For purification of FC b2 a new method of affinity chromatography was developed and purified preparations of the enzyme were used for the construction of the highly selective enzymatic kits and amperometric biosensor for L-lactate analysis in human liquids and foods.

Analytica Chimica Acta, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Biosensors - Emerging Materials and Applications, 2011

Biosensors-Emerging Materials and Applications 402 interfering substances into a sensitive biosel... more Biosensors-Emerging Materials and Applications 402 interfering substances into a sensitive bioselective layer and the transducer surface, or creates a diffusion barrier for the analyte. Such membrane structures increase the stability of the biorecognition element, enhance its selectivity and provide the diffusion limitations for biochemical reactions. Electrochemical, optical, piezoelectric, thermoelectric, transistor, acoustic and other elements are used as transducers in biosensor systems. Electrochemical (amperometric, potentiometric, conductometric) and optical (surface plasmon resonance) devices are the most exploited transducers in commercially available biosensors (Commercial Biosensors, 1998). Basically, biosensors can be regarded as information transducers in which the energy of biospecific interactions is transformed into information about the nature and concentration of an analyte in the sample. The most essential advantages of biosensors are excellent chemical selectivity and high sensitivity, possibility of miniaturization and compatibility with computers. Their drawbacks are limited stability and a rather complicated procedure for preparation of the biologically active material. Enzyme biosensors are the most widespread devices (Zhao & Jiang, 2010); many of them are produced commercially. Enzyme biosensors are characterized by their high selectivity. They also provide fast output due to high activity and high local enzyme concentration in a sensitive layer. The drawbacks of enzyme biosensors are insufficient stability and the high price of purified enzymes. Cell sensors, especially microbial ones, have been actively developed only in recent years (Shimomura-Shimizu & Karube, 2010a, 2010b; Su et al., 2011). Cell biosensors have a range of considerable advantages when compared to their enzyme analogues: availability of cells, low price and simple procedure of cell isolation, possibility to use long metabolic chains, avoiding purification of enzymes and coenzymes, advanced opportunity for metabolic engineering, integrity of the cell response (important in assaying total toxicity and mutagenic action of environmental pollutants), possibility to retain viability of sensoring cells and even to provide their propagation, and, in some cases, higher stability of cell elements compared to enzyme ones. The main drawbacks of microbial biosensors are a rather low signal rate due to a lower concentration of enzymes involved in cellular response, as well as low selectivity of cell output (e.g. in the case of microbial O 2 electrode sensors due to a broad substrate specificity of cellular respiration). These drawbacks are not absolute, taking into account recent progress in genetic engineering and the possibility to over-express the key analytical enzyme in the cell (Gonchar et al., 2002). Most biosensors have been created for clinical diagnostics (D'Orazio, 2003; Song et al., 2006; Belluzo et al., 2008). They exploit enzymes as biocatalytic recognition elements and immunoreagents and DNA fragments as affinity tools for biorecognition of the target analytes (metabolites, antigens, antibodies, nucleic acids) coupled to electrochemical and optical modes of transduction. For simultaneous detection of multiple analytes, microarray techniques are developed for automated clinical diagnostics (Seidel & Niessner, 2008). For continuous monitoring of living processes, reagentless implantable biosensors have been developed (Wilson & Ammam, 2007). Biosensors are regarded as very promising tools for clinical cancer testing (Rasooly & Jacobson, 2006; Wang, 2006). New genomic and proteomic approaches are being used for revealing cancer biomarkers related with genetic features, changes in gene expression, protein profiles and post-translational modifications of proteins. Recent progress in nanobiotechnology allows using nanomolecular approaches for clinical diagnostic procedures (Salata, 2004; Jain, 2007). The most important applications are www.intechopen.com

Environmental Biotechnology, 1995

An enzyme-mediated reaction was proposed for the photometric assay of formaldehyde by using alcoh... more An enzyme-mediated reaction was proposed for the photometric assay of formaldehyde by using alcohol oxidase, peroxidase and effective chromogenic substrate. This method was shown to be rather sensitive but not specific (methanol and ethanol also give a positive reaction).

Science and innovation, 2017

For the time, no screening test kits for L-arginine monitoring in biological fluids, including th... more For the time, no screening test kits for L-arginine monitoring in biological fluids, including the blood, have been available in the arsenal of domestic clinical diagnostics. The Argitest enzymatic kit is based on the enzymatic-chemical method of L-arginine quantitative analysis developed using different forms of recombinant human liver arginase I (arginase) and arginine deiminase. The method is highly selective, cheap, simple, and fast. It is remarkable for stability of enzymes and final products. The article demonstrates the possibility of using recombinant arginine-selective enzymes in composition of Argitest kit. The catalytic and analytic characteristics of these enzymes have been studied. It has been shown that each enzyme can be used as a component of enzymatic kit.

RSC Advances

Novel Zn/Cd/Cubd nanozymes possesses the ability to mimic coenzyme-dependent selenite reductase. ... more Novel Zn/Cd/Cubd nanozymes possesses the ability to mimic coenzyme-dependent selenite reductase. A new amperometric biosensor for determination of selenite was constructed.

RSC Advances

Novel colorimetric method based on alginate beads encapsulated with nPtCu and alcohol oxidase hav... more Novel colorimetric method based on alginate beads encapsulated with nPtCu and alcohol oxidase have been developed and optimized.

Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies

Nanozymes, which have high enzyme-like activity of natural enzymes, are very promising for analyt... more Nanozymes, which have high enzyme-like activity of natural enzymes, are very promising for analytical purposes, in particular, for the development of methods for sensitive, quantitative detection of practically important analytes – biomarkers of common diseases or pharmaceutical products. Recently, it has been reported that artificial enzymes with laccase-like activity or “nanolaccases (nLacs),” can serve as catalytic elements for the creation of sensitive methods for catecholamines. Our work aimed to obtain laccase-like nanozymes and characterize and demonstrate their suitability for spectrophotometric adrenaline (AD) analysis. In this article, we report on preparing five hexacyanoferrate nanoparticles (HCF NPs) that possess laccase-like activity, particularly, Co-HCF, Ni-HCF, Mn-HCF, Zn-HCF, and Cu-HCF. Among the investigated nLacs, Cu-HCF was selected and characterized. It was shown that Cu-HCF reveals the highest activities, is stable in various pH conditions in the range 3.0–6....