Search results for " enzyme"
showing 10 items of 791 documents
An in vitro tool to assess cytochrome P450 drug biotransformation-dependent cytotoxicity in engineered HepG2 cells generated by using adenoviral vect…
2011
Many adverse drug reactions leading to hepatotoxicity are caused by the cytochrome P450-dependent activation of non-toxic drugs or chemicals into reactive metabolites. To this end, adenoviruses were used as a tool to efficiently deliver specific CYP genes into cultured cells (i.e., human hepatoma cell line HepG2). Recombinant-defective adenoviral vectors encoding for genes CYP3A4 (Adv-CYP3A4), CYP2E1 (Adv-CYP2E1), CYP2A6 (Adv-CYP2A6) and CYP1A2 (Adv-CYP1A2) were used to confer specific CYP drug metabolic capabilities to HepG2 cells. Upgraded cells transiently expressed single specific cytochrome P450 enzymatic activities in terms of the number of the infecting virus particles used in their …
Arthropod-induced neoplastic formations on trees change photosynthetic pigment levels and oxidative enzyme activities
2005
Abstract In order to test the hypothesis that arthropod-induced neoplastic formations on trees affect biochemical characteristics of both the newly formed galls and host plant tissues, biochemical characteristics with a possible adaptive role were determined in nine gall-former–host tree combinations. Photosynthetic pigments, extractable protein content, and oxidative enzyme activities were determined in gall tissues, leaf tissues of galled leaves, and leaves on ungalled tree branches. Neoplastic tissues were characterized by a low content of photosynthetic pigments, decreased chlorophyll a/b ratio, lower extractable protein content, and decreased activities of peroxidase and polyphenol oxi…
Wound-induced responses in leaves of strawberry cultivars differing in susceptibility to spider mite
2002
Summary The effect of leaf detachment and wounding on the activities of oxidative enzymes and ethylene production was studied in strawberry (Fragaria × ananassa) cultivars, differing in susceptibility to the spider mite (Tetranychus urticae Koch.). Strawberry plants were cultivated during winter in two growth conditions - with and without overwintering, in greenhouse and laboratory, respectively. Polyphenol oxidase activity, peroxidase activity and catalase activity in strawberry leaves depended on the cultivar analysed, type of treatment (detachment or detachment and wounding), as well as on plant growth conditions. Activities of all analysed enzymes were higher in control plants grown in …
An ab initio conformational study on captopril
2003
Abstract Captopril can interact regio- and stereo-specifically with various functional groups present at the active site of angiotensin converting enzyme (ACE). Since no X-ray structure of ACE is available, Captopril, as an ACE inhibitor may be used as a ‘molecular caliper’, to estimate upper and lower bound values for separation d, where the mercaptidic terminal group of the molecule is linked to the enzyme Zn2+ cofactor, while the carboxylate links via an hydrogen bond to the guanidine moiety of an arginine side chain. As the results of this Ab Initio study, the conformations of the dianionic form of the full captopril molecule are reported here.
�pfels�urestoffwechsel bei Saccharomyces
1973
1. Aus Saccharomyces cerevisiae St. 79 konnte durch Protamin-und Ammoniumsulfatfallung sowie durch Chromatographie an DEAE-Cellulose ein Malatenzym [l-Malat: NAD(P) Oxidoreduktase, decarboxylierend, E.C. 1.1.1.38 oder 40] angereichert und von Malat-Dehydrogenase (l-Malat: NAD Oxidoreduktase, E.C. 1.1.1.37) weitgehend abgetrennt werden. 2. Neben Mn++-Ionen benotigt das Malatenzym der Hefe NAD oder NADP, bei einem optimalen pH-Wert von 7,5. Es ist spezifisch fur l-Malat, d-Malat wird nicht umgesetzt. Die Enzympraparate decarboxylierten Oxalessigsaure bei Abwesenheit von NAD. 3. Die Km Werte von Malatenzym sind fur l-Malat 5 · 10-2 M, fur NAD 5 · 10-4 M und fur Mangan 1,4 · 10-4 M. 4. Ein Zusa…
The contribution of P. acidilactici, L. plantarum, and L. curvatus starters and L-(+)-lactic acid to the acrylamide content and quality parameters of…
2017
Abstract Lactic acid bacteria (LAB) from spontaneous rye sourdough were isolated, identified, and characterized by their growth, acidification rate, and carbohydrate metabolism. The isolated LAB were used for production of rye sourdough, and the influence of sourdough on mixed rye - wheat bread quality and acrylamide formation was evaluated. In addition, comparative studies by using acidification with L-(+)-lactic acid for mixed rye – wheat bread production were performed. Isolated LAB (P. acidilactici, L. plantarum, L. curvatus) demonstrated versatile carbohydrate metabolism, grown at 30 °C and 37 °C, and acidic tolerance. When the isolated strains were used for rye sourdough production, t…
Action de la chlorhexidine sur l'expression de la virulence de
1999
Abstract Candida albicans is an opportunistic yeast. Its pathogenicity is linked to the susceptibility of the host surface as well as to particular factors of the strain: adhesion, filamentous growth and secretion of proteolytic enzymes. Chlorhexidine digluconate is an antiseptic with fungicidal properties. The action of the antiseptic on the growth of the yeast shows a minimal inhibitory concentration (MIC) at 50 μg·mL−1 and a minimal fungicidal concentration (MFC) at 100 μg·mL−1. The consequences of antiseptic treatment are studied using two indicators of pathogenicity: filamentation and the secretion of acid proteinase. Concerning the morphological indicator, a complete inhibition of fil…
Potential Roles of Peroxisomes in Alzheimer's Disease and in Dementia of the Alzheimer's Type
2012
In Alzheimer's disease (AD) and dementia of the Alzheimer's type (DAT), the role played by peroxisomes is not well known. Peroxisomes are present in all eukaryotic cells, with the exception of erythrocytes. They are involved in the β-oxidation process of long-chain fatty acids, very-long-chain fatty acids, and branched-chain fatty acids. They participate in the α-oxidation of phytanic acid, the biosynthesis of bile acids, and the breakdown of eicosanoids. Peroxisomes are also involved in the synthesis of specific fatty acids such as docosahexaenoic acid (DHA), which is essential for the brain and retina, and plasmalogens (PLGN), which play crucial roles in neural cells and are essential com…
Stabilization of anti-leukemic enzyme l-asparaginase by immobilization on polysaccharide levan
2001
Abstract Biologically active fructose polymer levan from Zymomonas mobilis of different molecular mass (75 and 2000 kDa) was covalently coupled to anti-leukemic enzyme Erwinia carotovora l -asparaginase. The method used for the immobilization of the enzyme involved periodate oxidation of the polysaccharide, followed by reductive alkylation. A gentle periodate oxidation of levan (oxidation degree ≤24%) resulted in the highest residual enzyme activity (≥55%). The K m(app.) of glycoconjugates was higher than the K m of native l -asparaginase. The conjugation of l -asparaginase widened the optimum pH range of the enzyme. The electrophoretic mobility in polyacrylamide gel of glycoconjugates obta…
Encapsulation of cytochrome C by multilayer microcapsules. A model for improved enzyme immobilization
1997
Cytochrome C was used as a model compound to study the behavior of proteins during the encapsulation procedure in alginate microcapsules and the loss by diffusion during storage. Alginate gel beads were coated with a multilayer membrane consisting of alternating layers of poly(N-vinylamine) and poly(acrylic acid) or water soluble anionic cellulose derivatives, respectively. To obtain high encapsulation yields, it is recommended to use the lowest possible concentration of salts in the precipitation bath. Loss during storage (and use) is minimized by applying at least two polycation/polyanion double layers for the membrane. Cellulose derivatives are superior over poly(acrylic acid). Single la…