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'Singlet Oxygen' in keywords Facet   section ZfN Section C  [X]
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1985 (1)
1979 (1)
1976 (1)
1Author    I. Basic, KineticsHartmut Schmidt, Peter RosenkranzRequires cookie*
 Title    On the Mechanism of the Acridine Orange Sensitized Photodynamic Inactivation of Lysozyme  
 Abstract    The kinetics of the photodynamic desactivation of lysozyme in presence of acridine orange as the sensitizer have been investigated in detail varying oxygen, protein, dye concentration, ionic strength and pH value. The kinetics can be approximately described as an over all pseudo-first-order rate process. Changing the solvent from water to D20 or by quenching experiments in pres­ ence of azide ions it could be shown that the desactivation of lysozyme is caused exclusively by singlet oxygen. The excited oxygen occurs via the triplet state of the dye with a rate constant considerably lower than that to be expected for a diffusionally controlled reaction. Singlet oxygen reacts chemically (desactivation, k —2.9 x 107 M -1 sec-1) and physically (quenching process, k = 4.1 x 108 m — 1 sec-J) with the enzyme. The kinetical analysis shows that additional chemical reac­ tions between singlet oxygen and lysozyme would have only little influence on the kinetics of the desactivation as long as their products would be enzymatically active and their kinetical constants would be less than about 1 x 1 0 8 m -1 sec-1. 
  Reference    (Z. Naturforsch. 31c, 29 [1976]; received July 7/September 19 1975) 
  Published    1976 
  Keywords    Photodynamic Effect, Singlet Oxygen, Lysozyme, Acridine Orange, Kinetics 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0029.pdf 
 Identifier    ZNC-1976-31c-0029 
 Volume    31 
2Author    KennethE. Pallett, AlanD. DodgeRequires cookie*
 Title    The Role of Light and Oxygen in the Action of the Photosynthetic Inhibitor Herbicide Monuron  
 Abstract    Monuron treatment of detached flax cotyledons caused a rapid inhibition of C 02 fixation in darkness and light. Chlorophyll breakdown was promoted by increased light intensity. Ethane generation, an indicator of membrane damage, increased as the chlorophyll level decreased. The carotene pigments were destroyed more rapidly than the xanthophylls and chlorophylls. Treatment of cotyledons with monuron in the absence of oxygen almost prevented carotenoid and chlorophyll loss. The addition of the singlet oxygen quencher DABCO delayed chlorophyll breakdown. The results are discussed in relation to a role for singlet oxygen in the herbicidal action of monuron. 
  Reference    Z. Naturforsch. 34c, 1058—1061 (1979); received May 29 1979 
  Published    1979 
  Keywords    Herbicidal Action of Monuron, Light, Oxygen, Singlet Oxygen, Plant Pigments 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1058.pdf 
 Identifier    ZNC-1979-34c-1058 
 Volume    34 
3Author    Krzysztof Lichszteld, Zygmunt Machoy, Anna StępińskaRequires cookie*
 Title    Chemiluminescence in the Coupled Oxidation of Lecithin and Ascorbate  
 Abstract    Chem ilum inescence (CL) that appears during oxidation o f lecithin and ascorbate has been studied. A simple system consisting only o f purified lecithin, which has one double bond, and ascorbate as a physiological reductant with a low redox potential, was used. The CL spectrum o f lecithin contain a strong band lying in the near infrared, and three bands at 20 900 cm -1, 17 700 cm -1 and 15 800 cm -1, being characteristic o f singlet m olecular oxygen (1O a). The effect o f * 0 2 quenchers on both autooxidation processes has also been investigated. The obtained results indicate that the main emitter is the *0 2. An addition o f ascorbate to the system lecithin plus buffer causes a decrease o f CL intensity. That is a result o f stronger quenching properties o f ascorbate and not due to efficiency o f the generation o f *0 2 . 
  Reference    Z. Naturforsch. 40c, 223—226 (1985); received Septem ber 13 1984 
  Published    1985 
  Keywords    Lipid Peroxidation, Singlet Oxygen, Chem ilum inescence, Lecithin, Ascorbic Acid 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0223.pdf 
 Identifier    ZNC-1985-40c-0223 
 Volume    40