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Wyszukujesz frazę "enzyme inhibition" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Correlation between butyrylcholinesterase variants and sensitivity to soman toxicity
Autorzy:
Dimov, Dimo
Kanev, Kamen
Dimova, Ivanka
Powiązania:
https://bibliotekanauki.pl/articles/1039756.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
enzyme inhibition/reactivation
soman toxicity
Butyrylcholinesterase variants
Opis:
Butyrylcholinesterase (BChE) is synthesized in the liver and found in high concentrations in blood plasma, liver, heart, pancreas, vascular endothelium, skin, brain white matter, smooth muscle cells and adipocytes. BChE is a non specific enzyme that hydrolyzes different choline esters (succinylcholine, mivacurium) and many other drugs such as aspirin, cocaine and procaine. The enzyme is also considered as a bioscavenger due to its ability to neutralize the toxic effects of organophosphorus compounds (nervous system fs agents) such as soman. BChE displays several polymorphisms that influence its serum activity; therefore they could determine the individual sensitivity to chemical nerve agents. In this study, we investigated the correlation between BChE variants and the degree of enzyme inhibition and reactivation after soman application on blood samples of 726 individuals. The blood samples of individuals expressing abnormal variants, were more sensitive to soman compared to variants of homozygotes and heterozygotes for U-allele. We found significant differences in the degree of enzyme reactivation between different variants (with and without U-presence).
Źródło:
Acta Biochimica Polonica; 2012, 59, 2; 313-316
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition of the helicase activity of HCV NTPase/helicase by 1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide-5-triphosphate (ribavirin-TP).
Autorzy:
Borowski, Peter
Lang, Melanie
Niebuhr, Andreas
Haag, Annemarie
Schmitz, Herbert
Schulze zur Wiesch, Julian
Choe, Joonho
Siwecka, Maria
Kulikowski, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1044103.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
ribavirin-5'-triphosphate
enzyme inhibition
HCV helicase
Opis:
In the presented study the ribavirin-TP - an established inhibitor of the NTPase activity of the superfamily NTPase/helicases II - was investigated as an inhibitor of the unwinding activity of the hepatitis C virus (HCV) NTPase/helicase. The kinetics of the reaction revealed that ribavirin-TP reduces the turnover number of the helicase reaction by a mechanism that does not correspond to that of the inhibition of the NTPase activity. Our results suggest that derivatives of ribavirin-TP with enhanced stability towards hydrolytic attack may be effective inhibitors of the enzyme.
Źródło:
Acta Biochimica Polonica; 2001, 48, 3; 739-744
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An easy procedure to transform the ratio of two polynomials of first degree into Michaelis-Menten-type equations. Application to the ordered Uni Bi enzyme mechanism.
Autorzy:
Fontes, Rui
Ribeiro, João
Sillero, Antonio
Powiązania:
https://bibliotekanauki.pl/articles/1044439.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
rectangular hyperbolas
enzyme inhibition
enzyme equations
enzyme kinetics
graphical presentations
Opis:
It is not always clear that some equations affected by complicated factors can, actually, be interpreted as a ratio of two polynomials of first degree and so that they can be, in general, represented by rectangular hyperbolas. In this paper we present an easy procedure to rearrange those equations into Michaelis-Menten-type equations and so to make the aspects of these rectangular hyperbolas more clear, particularly for researchers familiar with general biochemistry. As an example, the method is applied to transform the classical rate equation of the Cleland×s Ordered Uni Bi enzyme mechanism.
Źródło:
Acta Biochimica Polonica; 2000, 47, 1; 259-268
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ATP-binding domain of NTPase/helicase as a target for hepatitis C antiviral therapy.
Autorzy:
Borowski, Peter
Mueller, Oliver
Niebuhr, Andreas
Kalitzky, Matthias
Hwang, Lih-Hwa
Schmitz, Herbert
Siwecka, Maria
Kulikowski, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1044428.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
ribavirin-5'-triphosphate
enzyme inhibition
HCV NTPase/helicase
Opis:
To enhance the inhibitory potential of 1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin) vs hepatitis C virus (HCV) NTPase/helicase, ribavirin-5'-triphosphate (ribavirin-TP) was synthesized and investigated. Ribavirin-TP was prepared with the use of modified Yoshikawa-Ludwig-Mishra-Broom procedure (cf. Mishra & Broom, 1991, J. Chem. Soc., Chem. Commun, 1276-1277) involving phosphorylation of unprotected nucleoside. Kinetic analysis revealed enhanced inhibitory potential of ribavirin-TP (IC50=40 μM) as compared to ribavirin (IC50 > 500 μM). Analysis of the inhibition type by means of graphical methods showed a competitive type of inhibition with respect to ATP. In view of the relatively low specificity towards nucleoside-5'-triphosphates (NTP) of the viral NTPase/helicases, it could not be ruled out that the investigated enzyme hydrolyzed the ribavirin-TP to less potent products. Investigations on non- hydrolysable analogs of ribavirin-TP or ribavirin-5'-diphosphate (ribavirin-DP) are currently under way.
Źródło:
Acta Biochimica Polonica; 2000, 47, 1; 173-180
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Black Trumpet, Craterellus cornucopioides (L.) Pers.: Culinary Mushroom with Angiotensin Converting Enzyme Inhibitory and Cytotoxic Activity
Autorzy:
Radović, Jelena
Leković, Aleksandra
Tačić, Ana
Dodevska, Margarita
Stanojković, Tatjana
Marinković, Tijana
Jelić, Čedomir
Kundakovic-Vasović, Tatjana
Powiązania:
https://bibliotekanauki.pl/articles/2051038.pdf
Data publikacji:
2022-06-06
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
Craterellus cornucopioides
β-glucan
nutrients
angiotensin converting enzyme inhibition
cytotoxicity
Opis:
Nutritional value and chemical composition, including the content of vitamins, fatty acids, 5’-nucleotides and nucleosides and amino acids, as well as biological activities, including antioxidant, angiotensin converting enzyme (ACE) inhibitory and cytotoxic activity of black trumpet (Craterellus cornucopioides (L.) Pers.) were tested in vitro. C. cornucopioides was low in energy, fat and carbohydrate contents, but rich in dietary fibre, especially β-glucan as well as niacin and α-tocopherol. The content of essential and non-essential free amino acids was 1.49 and 5.48 mg/g dry weight (dw). The nucleosides and 5’-nucleotides were determined at 1.84 and 3.99 mg/g dw, respectively. The share of unsaturated fatty acids (UFAs) was 75.92% with oleic acid as the major UFA. Cyclohexane and dichloromethane extracts expressed significant cytotoxic activity against selected cell lines, human epithelial cervical cancer cells (HeLa), adenocarcinomic human alveolar basal epithelial cells (A549), colorectal cancer cells (LS174) and normal MRC-5 human embryonic lung fibroblast cells (IC50 of 78.3–155.6 μg/mL). ACE inhibitory activity of the aqueous extract was strong with an IC50 of 0.74 μg/mL. It can be concluded that black trumpet is a good source of nutrients, such as vitamins, dietary fibres, amino acids, nucleotides and fatty acids, which contribute to the overall nutritional value of this fungus with potential for ACE inhibitory activity and use in anti-hypertensive diet.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2022, 72, 2; 171-181
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition and activation of enzymes. The effect of a modifier on the reaction rate and on kinetic parameters.
Autorzy:
Fontes, Rui
Ribeiro, João
Sillero, Antonio
Powiązania:
https://bibliotekanauki.pl/articles/1044438.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
enzyme inhibition
enzyme modifier
rapid equilibrium kinetics
I50
enzyme activation
enzyme kinetics
graphical presentations
Opis:
A combined analysis of enzyme inhibition and activation is presented, based on a rapid equilibrium model assumption in which one molecule of enzyme binds one molecule of substrate (S) and/or one molecule of a modifier X. The modifier acts as activator (essential or non-essential), as inhibitor (total or partial), or has no effect on the reaction rate (v), depending on the values of the equilibrium constants, the rate constants of the limiting velocity steps, and the concentration of substrate ([S]). Different possibilities have been analyzed from an equation written to emphasize that v = Ł([X]) is, in general and at a fixed [S], a hyperbolic function. Formulas for Su (the value of [S], different from zero, at which v is unaffected by the modifier) and vsu (v at that particular [S]) were deduced. In Lineweaver-Burk plots, the straight lines related to different [X] generally cross in a point (P) with coordinates (Su, vsu). In certain cases, point P is located in the first quadrant which implies that X acts as activator, as inhibitor, or has no effect, depending on [S]. Furthermore, we discuss: (1) the apparent Vmax and Km displayed by the enzyme in different situations; (2) the degree of effect (inhibition or activation) observed at different concentrations of substrate and modifier; (3) the concept of Ke, a parameter that depends on the concentration of substrate and helps to evaluate the effect of the modifier: it equals the value of [X] at which the increase or decrease in the reaction rate is half of that achieved at saturating [X]. Equations were deduced for the general case and for particular situations, and used to obtain computer-drawn graphs that are presented and discussed. Formulas for apparent Vmax, Km and Ke have been written in a way making it evident that these parameters can be expressed as pondered means.
Źródło:
Acta Biochimica Polonica; 2000, 47, 1; 233-257
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Techno-Functional and Bioactive Properties and Chemical Composition of Guava, Mamey Sapote, and Passion Fruit Peels
Autorzy:
López-Martínez, Leticia X.
Villegas-Ochoa, Mónica A.
Domínguez-Avila, J. Abraham
Yahia, Elhadi M.
Gonzalez-Aguilar, Gustavo A.
Powiązania:
https://bibliotekanauki.pl/articles/24024619.pdf
Data publikacji:
2023-11-02
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
tropical fruits
phenolic profile
antioxidant potential
enzyme inhibition
glucose adsorption capacity
fat/oil binding capacity
sodium cholate binding capacity
Opis:
Due to their nutritional and sensorial characteristics, tropical fruits like guava, mamey sapote, and passion fruit are regularly incorporated into daily diets. Their by-products, especially peels, are approximately 10 to 35% of their weight and possess an important content of bioactive compounds, such as dietary fiber and phenolics. The nutritional, technological, physio-functional properties and phenolic compound compositions of guava, mamey sapote, and passion fruit peels were studied. Peels had promising techno- and physio-functional characteristics, good dietary fiber contents (45.18-61.42 g/100 g), and phenolic profiles with ferulic acid, gallic acid, p-coumaric, and catechin as the main compounds. Peel powders also showed excellent DPPH radical scavenging activity (125.3–252.4 µmol TE/100 g) and Trolox equivalent antioxidant capacity, TEAC (369.2–656.8 µmol TE/100 g). The α-amylase and lipase inhibitory activity varied from 28.15 to 51.4% and 30.89 to 57.15%, respectively. Higher values of α-glucosidase inhibition capacity were found, ranging from 51.64 to 70.32%. The chemical composition and properties reported in the present work suggest that peel powders of these guava, mamey sapote, and passion fruit could be used as constituents in different foods, such as bakery and meat goods, with beneficial health effects like control of hyperglycemia, improved intestinal function, and control of overweight; however, more studies are necessary for animal models and humans to confirm these bioactivities conclusively.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2023, 73, 4; 311-321
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method for detecting cross-inhibition effects in the environmental biocatalytic processes
Autorzy:
Herke, Z.
Maskow, T.
Nemeth, Z.I.
Powiązania:
https://bibliotekanauki.pl/articles/80851.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
biocatalysis
microorganism
enzyme
bioremediation
inhibition
modelling
regression analysis
principal component analysis
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2015, 96, 4
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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