Seibutsu Butsuri
Online ISSN : 1347-4219
Print ISSN : 0582-4052
ISSN-L : 0582-4052
Volume 44 , Issue 4
Issue 254
Showing 1-10 articles out of 10 articles from the selected issue
  • Hideyuki KUMITA, Yoshitsugu SHIRO
    2004 Volume 44 Issue 4 Pages 155-160
    Published: 2004
    Released: July 22, 2004
    From chemical point of view, the NO reduction to N2O is one of the most attractive subjects, since it contains the N-O bond cleavage and N-N bond formation with aid of two electrons and two protons. Nitric oxide reductase (NOR) is a key enzyme for this reaction in biological denitrification processes. Two types of NORs have been isolated from some microorganisms and characterized; one is a soluble cytochrome P450-type enzyme from fungi, whereas the other is a membrane-bound cytochrome bc-type complex from denitrifying bacteria. These NORs effectively catalyze the NO reduction in a quite different mechanism. Here we summarize the current results in the mechanistic study of NO reduction reaction conducted by each enzyme, and discuss their molecular mechanism based on their structural and functional information.
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  • Kazuo OHKI
    2004 Volume 44 Issue 4 Pages 161-165
    Published: 2004
    Released: July 22, 2004
    The membrane proteins require lipids in order to express their function. The function is under the influence of structure and physical properties of the lipid membrane surrounding the proteins. The non-bilayer structure induced by non-bilayer forming lipids is concerned in various membrane functions, such as membrane fusion during endocytosis. The physical properties of non-bilayer forming lipids are investigated by fluorescence measurements using an environment-sensitive probe, laurdan, differential scanning calorimetry and density meter. The results suggest relationship between the physical properties of non-bilayer forming lipid and the membrane functions.
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  • Masashi MIYAKAWA, Masashi INOUE, Hiroki AKIYAMA, Eriko OHMORI
    2004 Volume 44 Issue 4 Pages 166-171
    Published: 2004
    Released: July 22, 2004
    Double whole cell recordings and voltage-sensitive dye imaging from the dendrites of pyramidal neurons revealed that the membrane of the apical dendrites is electrically leakier than that of other locations. A theoretical analysis predicts that the impact of synaptic inputs on the distal part of the dendrites can be more effective when the membrane resistivity is lower towards the end of the dendrite than when the resistivity is uniform. The distribution of resistivity along the soma-dendritic axis may have important implications on synaptic integration much as the active electrical properties of the dendrites.
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