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1Author    E. Horozova, N. Dimcheva, Z. JordanovaRequires cookie*
 Title    Peroxidase-Like Activity of Catalase Immobilized on Carbon Materials  
 Abstract    The immobilization of catalase was carried out from enzyme solutions in acid (pH < 3.5) and alkaline (pH > 1 1) medium on two kinds of soot differing by the average size of the particles. Under these conditions the peroxidase-like activity of immobilized catalase in the oxidation of phenol has been studied. The effect of the initial concentration of the substrate on the rate of the process catalysed by catalase immobilized on the soot of finer-grained structure has been studied. The relationships obtained are described by the equation of Mi-chaelis-M enten. The kinetic parameters (the constant of Michaelis -K m, the maximum reac­ tion rate -Vmax, the rate constant -k and the activation energy -Ea) of the process were calculated. It was found that catalase absorbed on the soot of larger globular particles does not take part in the peroxidase oxidation of phenol. 
  Reference    Z. Naturforsch. 53c, 863—8 (1998); received March 3/May 15 1998 
  Published    1998 
  Keywords    Catalase, Immobilized Enzyme, Carbon Materials, Peroxidase-Like Activity 
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 TEI-XML for    default:Reihe_C/53/ZNC-1998-53c-0863.pdf 
 Identifier    ZNC-1998-53c-0863 
 Volume    53 
2Author    Jürgen FeierabendRequires cookie*
 Title    Comparison of the Action of Bleaching Herbicides  
 Abstract    Among chlorosis-inducing herbicides that interfere with carotenoid synthesis two groups o f different potency can be discriminated (group 1; aminotriazole amd haloxidine; group 2 with more extensive photodestructions: pyridazinone herbicides and difunon). After application o f herbicides o f group 2 colored carotenoids were com pletely absent and preexisting chlorophyll was degraded by photochem ical reactions requiring high light intensity and 0 2, that occurred also at 0 °C . In treatments with group 1 herbicides direct photodegradation o f chlorophyll was not sufficient to generate the chlorosis. Light-induced interference with constituents o f the chloroplast protein synthesis apparatus being more sensitive to ph otooxidative dam age than chlorophyll, appeared to indirectly m ediate the chlorosis. In the absence o f chloroplast protein synthesis further chlorophyll accum ulation is prevented. Photodegradation o f chlorophyll in the presence o f group 2 herbicides involved the participation o f 0 2~ radicals and was accom panied by lipid peroxidation. In all herbicide treatments the catalase activity o f the leaves was very low. Only in the presence o f group 2 herbicides chloroplast enzym es o f cytoplasm ic origin (e.g. NADP-glyceraldehyde-3-phosphate dehydrogenase) were also inactivated. Rapid inactivation o f catalase as well as o f N A D P-glyceraldehyde-3-phosphate dehydrogenase was induced by exposure o f dim-light-grown herbicide-treated leaves to bright light, also at 0 ° C . In treatments with herbicides o f group 2 also other peroxisom al enzymes (e.g. glycolate oxidate, hydroxy-pyruvate reductase) were affected. The elim ination o f these peroxisom al enzym es also appeared to depend on photooxidative processes o f the chloroplast. 
  Reference    Z. Naturforsch. 39c, 450 (1984); received N ovem ber 4 1983 
  Published    1984 
  Keywords    Bleaching Herbicides, Carotenoids, Catalase, Chlorosis, Leaf Peroxisom es, Photooxidation 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0450.pdf 
 Identifier    ZNC-1984-39c-0450 
 Volume    39 
3Author    E. Horozova, N. Dimcheva, Z. JordanovaRequires cookie*
 Title    Adsorption, Catalytic and Electrochemical Activity o f Catalase Immobilized on Carbon Materials  
 Abstract    The adsorption of catalase on two types of soot differing in their structure has been charac­ terized. The adsorption of this enzyme obeys the Tyomkin adsorption isotherm. It has been established that the catalase immobilized on soot and graphite takes part in the electrochem i­ cal oxidation of phenol. The enzyme activity of catalase immobilized on both types of soot was studied on the decomposition of hydrogen peroxide. The kinetic and activation param e­ ters of the processes studied have been determined. 
  Reference    Z. Naturforsch. 52c, 639—644 (1997); received May 5/July 3 1997 
  Published    1997 
  Keywords    Catalase, Immobilized Enzyme, Carbon Materials, Electrochemical and Biocatalytic Activity 
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 TEI-XML for    default:Reihe_C/52/ZNC-1997-52c-0639.pdf 
 Identifier    ZNC-1997-52c-0639 
 Volume    52 
4Author    SvetlanaB. Pashova3, LudmilaS. Slokoska3, PavlinaA. Dolashka-Angelovab, SpassenV. Vassilev3, PravdaD. Sheremetska3, MariaB. Angelova3Requires cookie*
 Title    Effect of Dissolved Oxygen Concentration on Superoxide Dismutase Production by Humicola lutea Cells  
 Abstract    Cultures of the fungal strain H um icola lutea 110 were grown in a 3-1 bioreactor. Effects of dissolved oxygen concentration (D O) on cell growth, intracellular protein content and antioxidant enzyme activities (SO D and catalase) were investigated. Controlling DO from 20 to 60% lead to: (I). The lethal phase of growth was reached faster; (ii) strong reduction of the intracellular protein content, and (iii) increase of antioxidant enzyme activities. The most efficient SOD biosynthesis was achieved at the 1st maximum of activity in the culture grown under D O uncontrolled conditions. 
  Reference    Z. Naturforsch. 54c, 1049—1054 (1999); received May 17/July 14 1999 
  Published    1999 
  Keywords    Superoxide Dismutase, Catalase, Production, Filamentous Fungi, D issolved Oxygen 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-1049.pdf 
 Identifier    ZNC-1999-54c-1049 
 Volume    54 
5Author    Elena Horozova, Nina Dimcheva, Zinaida JordanovaRequires cookie*
 Title    Catalytic Decomposition of 3-Chloroperoxybenzoic Acid by Immobilized Catalase in a Non-Aqueous Medium  
 Abstract    Catalytic activities of catalase (C A T) immobilized on graphite -G M Z ™ , soot -"N O R IT " and "PM -100" to mediate decomposition of 3-C l-C 6H 4CO O O H (3-C P B A) in ace-tonitrile have been investigated. Under these conditions, the kinetic param eters K m, k, E a, ^ a x , and Zo were calculated. Conclusions on a probable mechanism of the catalytic process observed were drawn from the calculated values of A G *, AH *, and AS*. A quantitative UV-spectrophotometrical approach was used as the basic analytical tool. The electrochem ical reduction of oxygen generated in enzyme catalysed 3-C P B A decomposition was examined with polarization curves method. 
  Reference    Z. Naturforsch. 55c, 55—5 (2000); received February 22/September 28 1999 
  Published    2000 
  Keywords    Catalase, Immobilized Enzyme, Carbon Materials, Acetonitrile Medium, Catalytic Activity 
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 TEI-XML for    default:Reihe_C/55/ZNC-2000-55c-0055.pdf 
 Identifier    ZNC-2000-55c-0055 
 Volume    55 
6Author    Jürgen Feierabend, Ulrike Schulz, Petra Kemmerich, Theresia LowitzRequires cookie*
 Title    On the Action of Chlorosis-Inducing Herbicides in Leaves  
 Abstract    The chlorosis induced by several different herbicides (group 1: aminotriazole, haloxidine; group 2: Sandoz 6706, difunon) in developing leaves of rye seedlings (Secale cereale L.) growing in light of 5,000 lx was, in addition to the absence of chlorophyll and carotenoids, accompanied by specific deficiencies of the 70 S ribosomes and of both chloroplastic and peroxisomal enzymes as previously described (Plant Physiol. 61, 1017 — 1022 (1978)) while growth and mitochondrial activities were little or not impaired. In dim light (10 lx) chlorophyll was formed and the chloroplastic and peroxisomal enzymes reached activities comparable to those in untreated leaves at 10 lx. Upon exposure to 30,000 lx a rapid bleaching of existing chlorophyll and a rapid inactivation of the plastidic enzyme NADP-glyceraldehydephosphate dehydrogenase occured after treatment with herbicides of group 2 but not in the presence of herbicides of group 1. After all treatments catalase was rapidly inactivated after transfer to high light intensity. The bleaching of chlorophyll and the enzyme inactivations occurred also at 0 °C. In the herbicide-bleached leaves grown at 5,000 lx the in vivo synthesis of (5-aminolevulinic acid was low and in the presence of Sandoz 6706 and difunon the capacity for protochlorophyll (ide) synthesis was largely inactivated. 
  Reference    Z. Naturforsch. 34c, 1036—1039 (1979); received June 5 1979 
  Published    1979 
  Keywords    Chlorosis-Inducing Herbicides, Photooxidation of Chlorophyll, Photoinactivation of Enzymes, Catalase, Cyanide-Insensitive Respiration 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1036.pdf 
 Identifier    ZNC-1979-34c-1036 
 Volume    34 
7Author    Marcelo Hermes-Lima, KennethB. StoreyRequires cookie*
 Title    Xanthine Oxidase and Xanthine Dehydrogenase from an Estivating Land Snail  
 Abstract    During arousal from estivation in land snails. Otala lactea, active metabolic functions are restored within minutes and oxygen consumption increases dramatically. During the transi­ tion from the hypoxic conditions of estivation to normoxia it is possible that xanthine oxidase (X O) in hepatopancreas contributes to the observed lipid peroxidation. Using a fluorometric assay that is based on the oxidation of pterin, the activities and som e properties of XO and X O +X D H (sum of XO and xanthine dehydrogenase activities) were measured in hepato­ 
  Reference    Z. Naturforsch. 50c, 685—6 (1995); received January ll/Ju ly 10 1995 
  Published    1995 
  Keywords    Metabolic Depression, Estivation Hydrogen Peroxide, Catalase, Oxidative Stress, Gastropod Mollusc, Otala lactea 
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 TEI-XML for    default:Reihe_C/50/ZNC-1995-50c-0685.pdf 
 Identifier    ZNC-1995-50c-0685 
 Volume    50