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  1. Article ; Online: Methylated derivatives of l-tyrosine in reaction catalyzed by l-amino acid oxidase: isotope and inhibitory effects.

    Pająk, Małgorzata

    Journal of biochemistry

    2020  Volume 168, Issue 5, Page(s) 509–514

    Abstract: l-Amino acid oxidase (LAAO) is widely distributed in nature and shows important biological activity. It induces cell apoptosis and has antibacterial properties. This study was designed to investigate the effect of methyl substituent on its activity as ... ...

    Abstract l-Amino acid oxidase (LAAO) is widely distributed in nature and shows important biological activity. It induces cell apoptosis and has antibacterial properties. This study was designed to investigate the effect of methyl substituent on its activity as methylated derivatives of l-tyrosine, labelled with short-lived B+ emitters, have been used in oncological diagnostics. To study isotope effects in the oxidative deamination of O-methyl-l-tyrosine, the deuterated isotopomer, i.e. O-methyl-[2-2H]-l-tyrosine, was synthesized by isotope exchange, catalyzed enzymatically by tryptophanase. Isotope effects were determined using the spectrophotometric non-competitive method. The values of isotope effects indicate that the α-C-H bond cleavage occurs in the rate determining step of the investigated reaction and α-hydrogen plays a role in the substrate binding process at the enzyme active site. The inhibitory effect on LAAO activity was studied with α-methyl-l-tyrosine and N-methyl-l-tyrosine. The mode of inhibition was determined based on Lineweavear-Burk plots intersections. α-Methyl-l-tyrosine has been found a mixed type inhibitor of the investigated enzyme, whereas N-methyl-l-tyrosine is a non-competitive inhibitor of LAAO.
    MeSH term(s) Animals ; Catalysis ; Crotalus/metabolism ; Isotope Labeling ; Kinetics ; L-Amino Acid Oxidase/antagonists & inhibitors ; L-Amino Acid Oxidase/chemistry ; L-Amino Acid Oxidase/metabolism ; Methylation ; Methyltyrosines/chemistry ; Methyltyrosines/pharmacology ; Substrate Specificity ; Tyrosine/analogs & derivatives ; Tyrosine/chemistry ; Tyrosine/pharmacology
    Chemical Substances Methyltyrosines ; Tyrosine (42HK56048U) ; L-Amino Acid Oxidase (EC 1.4.3.2)
    Language English
    Publishing date 2020-06-19
    Publishing country England
    Document type Journal Article
    ZDB-ID 218073-x
    ISSN 1756-2651 ; 0021-924X
    ISSN (online) 1756-2651
    ISSN 0021-924X
    DOI 10.1093/jb/mvaa066
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Kinetic and solvent isotope effects in oxidation of halogen derivatives of tyramine catalyzed by monoamine oxidase A.

    Pająk, Małgorzata

    Journal of biochemistry

    2019  Volume 167, Issue 1, Page(s) 49–54

    Abstract: The isotope effects approach was used to elucidate the mechanism of oxidative deamination of 3'-halotyramines, catalyzed by monoamine oxidase A (EC 1.4.3.4). The numerical values of kinetic isotope effect (KIE) and solvent isotope effect (SIE) were ... ...

    Abstract The isotope effects approach was used to elucidate the mechanism of oxidative deamination of 3'-halotyramines, catalyzed by monoamine oxidase A (EC 1.4.3.4). The numerical values of kinetic isotope effect (KIE) and solvent isotope effect (SIE) were established using a non-competitive spectrophotometric technique. Based upon KIE and SIE values, some of the mechanistic details of investigated reaction were discussed.
    MeSH term(s) Biocatalysis ; Fluorine Radioisotopes ; Humans ; Iodine Isotopes ; Kinetics ; Monoamine Oxidase/metabolism ; Oxidation-Reduction ; Solvents/chemistry ; Tyramine/metabolism
    Chemical Substances Fluorine Radioisotopes ; Iodine Isotopes ; Solvents ; Monoamine Oxidase (EC 1.4.3.4) ; monoamine oxidase A, human (EC 1.4.3.4.) ; Tyramine (X8ZC7V0OX3)
    Language English
    Publishing date 2019-10-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 218073-x
    ISSN 1756-2651 ; 0021-924X
    ISSN (online) 1756-2651
    ISSN 0021-924X
    DOI 10.1093/jb/mvz089
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: The Electrochemical Behavior of Unmodified and Pd-NPs Modified AB

    Hubkowska, Katarzyna / Pająk, Małgorzata / Soszko, Michał / Czerwiński, Andrzej

    Molecules (Basel, Switzerland)

    2023  Volume 28, Issue 2

    Abstract: The objective of this work was to study the electrochemical behavior of ... ...

    Abstract The objective of this work was to study the electrochemical behavior of AB
    Language English
    Publishing date 2023-01-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules28020856
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Zs.MO 81: Show issues

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  4. Article: The Effect of the Iridium Alloying and Hydrogen Sorption on the Physicochemical and Electrochemical Properties of Palladium.

    Hubkowska, Katarzyna / Pająk, Małgorzata / Czerwiński, Andrzej

    Materials (Basel, Switzerland)

    2023  Volume 16, Issue 13

    Abstract: Thin layers (up to 1 µm) of Pd-Ir alloys were electrodeposited from aqueous, galvanic baths of ... ...

    Abstract Thin layers (up to 1 µm) of Pd-Ir alloys were electrodeposited from aqueous, galvanic baths of PdCl
    Language English
    Publishing date 2023-06-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma16134556
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Enzymatic synthesis of halogen derivatives of L-phenylalanine and phenylpyruvic acid stereoselectively labeled with hydrogen isotopes in the side chain.

    Pałka, Katarzyna / Podsadni, Katarzyna / Pająk, Małgorzata

    Journal of labelled compounds & radiopharmaceuticals

    2023  Volume 66, Issue 11, Page(s) 362–368

    Abstract: Halogenated, labeled with deuterium, tritium or doubly labeled with deuterium and tritium in the 3S position of the side chain isotopomers of L-phenylalanine and phenylpyruvic acid were synthesized. Isotopomers of halogenated L-phenylalanine were ... ...

    Abstract Halogenated, labeled with deuterium, tritium or doubly labeled with deuterium and tritium in the 3S position of the side chain isotopomers of L-phenylalanine and phenylpyruvic acid were synthesized. Isotopomers of halogenated L-phenylalanine were obtained by addition of ammonia from isotopically enriched buffer solution to the halogenated derivative of (E)-cinnamic acid catalyzed by phenylalanine ammonia lyase. Isotopomers of halogenated phenylpyruvic acid were obtained enzymatically by conversion of the appropriate isotopomer of halogenated L-phenylalanine in the presence of phenylalanine dehydrogenase. As a source of deuterium was used deuterated water, as a source of tritium was used a solution of highly diluted tritiated water. The labeling takes place in good yields and with high deuterium atom% abundance.
    MeSH term(s) Deuterium/chemistry ; Halogens/chemical synthesis ; Halogens/chemistry ; Hydrogen ; Phenylalanine ; Tritium/chemistry ; Phenylpyruvic Acids/chemical synthesis ; Phenylpyruvic Acids/chemistry
    Chemical Substances Deuterium (AR09D82C7G) ; Halogens ; Hydrogen (7YNJ3PO35Z) ; Phenylalanine (47E5O17Y3R) ; phenylpyruvic acid (X7CO62M413) ; Tritium (10028-17-8) ; Phenylpyruvic Acids
    Language English
    Publishing date 2023-08-02
    Publishing country England
    Document type Journal Article
    ZDB-ID 196095-7
    ISSN 1099-1344 ; 0362-4803 ; 0022-2135
    ISSN (online) 1099-1344
    ISSN 0362-4803 ; 0022-2135
    DOI 10.1002/jlcr.4057
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Laboratory Tests of Concrete Beams Reinforced with Recycled Steel Fibres and Steel Bars.

    Pająk, Małgorzata / Wandzik, Grzegorz

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 22

    Abstract: This paper explores the possibility of the partial replacement of the longitudinal reinforcement in reinforced concrete (RC) beams with recycled steel fibres (RSF). Testing was focused on the contribution of two volume ratios of the RSF-0.5%, 1.0%. Basic ...

    Abstract This paper explores the possibility of the partial replacement of the longitudinal reinforcement in reinforced concrete (RC) beams with recycled steel fibres (RSF). Testing was focused on the contribution of two volume ratios of the RSF-0.5%, 1.0%. Basic compression and flexural tensile tests were performed to evaluate the effectiveness of the fibres following current standards. Additionally, the full-scale beams with and without conventional reinforcement were subjected to four-point bending tests. The results indicate that RSF improved the load-bearing capacity of the RC beams. Cooperation of RSF with the steel bars in carrying loads was proved. Findings from the Digital Image Correlation (DIC) revealed no impact on the cracking pattern of the RC beams.
    Language English
    Publishing date 2021-11-09
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14226752
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  7. Article: Laboratory Investigation and Numerical Modelling of Concrete Reinforced with Recycled Steel Fibers.

    Pająk, Małgorzata / Krystek, Małgorzata / Zakrzewski, Mateusz / Domski, Jacek

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 8

    Abstract: In the last decades, fiber reinforced concrete have emerged as the possible key to revolutionize civil engineering. Among different types of fibers employed in concrete technology to date, the application of recycled steel fibers produced from end-of- ... ...

    Abstract In the last decades, fiber reinforced concrete have emerged as the possible key to revolutionize civil engineering. Among different types of fibers employed in concrete technology to date, the application of recycled steel fibers produced from end-of-life car tires appears to be a viable approach towards environmentally friendly construction. In this study, we demonstrate the laboratory research and numerical analysis of concrete reinforced with waste steel fibers recovered during the recycling process of end-of-life car tires. Concrete mixes with the following fiber contents: 0.5%, 0.75%, 1.0%, 1.25%, and 1.5% per volume were prepared and then tested in three-point bending conditions. The laboratory investigation revealed highly boosted properties of concrete under flexure. We further performed the finite element method (FEM) analysis of 2D models using Atena software in order to develop a material model allowing the numerical modelling of recycled steel fibers reinforced concrete (RSFRC) behavior. The parameters of RSFRC material model have been modified using the inverse analysis until matching the experimental performance of the material. The results, being in good agreement with the laboratory investigation, have indicated a high potential of RSFRC for real scale construction applications.
    Language English
    Publishing date 2021-04-07
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14081828
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Isotope effects in the tyrosinase catalysed hydroxylation of l-tyrosine methyl derivatives.

    Pająk, Małgorzata / Kańska, Marianna

    Isotopes in environmental and health studies

    2018  Volume 54, Issue 5, Page(s) 548–557

    Abstract: To investigate isotope effects in the hydroxylation of [3',5'- ...

    Abstract To investigate isotope effects in the hydroxylation of [3',5'-
    MeSH term(s) Deuterium/chemistry ; Hydroxylation ; Kinetics ; Levodopa/metabolism ; Magnetic Resonance Spectroscopy ; Methyltyrosines/chemistry ; Methyltyrosines/metabolism ; Monophenol Monooxygenase/chemistry ; Monophenol Monooxygenase/metabolism ; Solvents ; Tyrosine/chemistry ; Tyrosine/metabolism
    Chemical Substances Methyltyrosines ; Solvents ; Tyrosine (42HK56048U) ; Levodopa (46627O600J) ; Deuterium (AR09D82C7G) ; Monophenol Monooxygenase (EC 1.14.18.1)
    Language English
    Publishing date 2018-08-07
    Publishing country England
    Document type Journal Article
    ZDB-ID 2100190-X
    ISSN 1477-2639 ; 1025-6016
    ISSN (online) 1477-2639
    ISSN 1025-6016
    DOI 10.1080/10256016.2018.1505722
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Isotope effects in the tyrosinase catalysed hydroxylation of l-tyrosine methyl derivatives

    Pająk, Małgorzata / Marianna Kańska

    Isotopes in environmental and health studies. 2018 Sept. 3, v. 54, no. 5

    2018  

    Abstract: To investigate isotope effects in the hydroxylation of [3′,5′-2H2]-α-methyl- and [3′,5′-2H2]-N-methyl-l-tyrosine, they were synthesised using acid catalysed isotope exchange at high temperature. The kinetic and solvent deuterium isotope effects on Vmax ... ...

    Abstract To investigate isotope effects in the hydroxylation of [3′,5′-2H2]-α-methyl- and [3′,5′-2H2]-N-methyl-l-tyrosine, they were synthesised using acid catalysed isotope exchange at high temperature. The kinetic and solvent deuterium isotope effects on Vmax and Vmax/Km parameters of tyrosinase in its action on methylated derivatives of l-tyrosine were determined using the non-competitive spectrophotometric method. Lineweaver–Burk plots were used to consider the inhibition type of O-methyl-l-tyrosine, revealing that it is an uncompetitive inhibitor of tyrosinase.
    Keywords catalytic activity ; deuterium ; enzyme inhibitors ; hydroxylation ; isotopes ; solvents ; spectrophotometers ; temperature ; tyrosine
    Language English
    Dates of publication 2018-0903
    Size p. 548-557.
    Publishing place Taylor & Francis
    Document type Article
    ZDB-ID 2100190-X
    ISSN 1477-2639 ; 1025-6016
    ISSN (online) 1477-2639
    ISSN 1025-6016
    DOI 10.1080/10256016.2018.1505722
    Database NAL-Catalogue (AGRICOLA)

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  10. Article: Effect of the Alloying Metal on the Corrosion Resistance of Pd-Rich Binary Alloys with Pt, Rh, and Ru in Sulfuric Acid.

    Hubkowska, Katarzyna / Kubisztal, Julian / Pająk, Małgorzata / Łosiewicz, Bożena / Czerwiński, Andrzej

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 11

    Abstract: The paper presents the study of the corrosion resistance of electrodeposited Pd and its binary alloys with Pt, Rh, and Ru on a polycrystalline Au substrate. The corrosion resistance was tested in 0.5 M sulfuric acid at room temperature using ... ...

    Abstract The paper presents the study of the corrosion resistance of electrodeposited Pd and its binary alloys with Pt, Rh, and Ru on a polycrystalline Au substrate. The corrosion resistance was tested in 0.5 M sulfuric acid at room temperature using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The morphology/composition and work function values were determined by scanning electron microscopy/energy-dispersive X-ray spectroscopy and scanning Kelvin probe, respectively. The obtained results revealed that the Pd electrode is the most resistant to corrosion, whereas the Pd-Ru electrode is the most susceptible to dissolution. It was found that the corrosion resistance of Pd-binary alloys decrease in the following order: Pd > Pd-Pt > Pd-Rh > Pd-Ru. This effect was assigned mainly to the difference in surface roughness factor of tested electrodes.
    Language English
    Publishing date 2021-05-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14112923
    Database MEDical Literature Analysis and Retrieval System OnLINE

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