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'ATPase' in keywords Facet   Publication Year 1982  [X]
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1982[X]
1Author    Hans Liidi, Bernhard Rauch, Wilhelm HasselbachRequires cookie*
 Title    The Influence of Detergents on the Ca2+-and Mg2+-Dependent Adenosine Triphosphatase of the Sarcoplasmic Reticulum  
 Abstract    During the stepwise solubilization of sarcoplasmic reticulum vesicles with detergents, the following changes in the structural and enzymatic properties of the preparation are observed: 1. The viscosity of the vesicular suspension initially rises. This change is accompanied by the formation of elongated tubules. Subsequently the membranes are completely desintegrated, resulting in a considerable reduction of the viscosity. 2. A decrease in the activity of the Ca2+-dependent ATPase, which is restored after complete solubilization. 3. A decrease in the change of intrinsic tryptophan-fluorescence on removal of calcium ions, which is also restored after complete solubilization. 4. A decrease of the calcium affinity of the ATPase. 5. A decrease in the amount of phosphorylated protein formed by the incorporation of inorganic phosphate. On the other hand, the amount of phosphoprotein formed from ATP is not affected during solubilization. 6. The dependence of the initial rates of phosphoprotein formation from inorganic phosphate on either magnesium or inorganic phosphate at low concentrations of the respective ligand changes from an S-shape profile to a normal hyperbolic profile after solubilization. 
  Reference    Z. Naturforsch. 37c, 299—307 (1982); received January 1982 
  Published    1982 
  Keywords    Sarcoplasmic Reticulum, ATPase, Detergent, Protein-Phosphorylation, Kinetics 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0299.pdf 
 Identifier    ZNC-1982-37c-0299 
 Volume    37 
2Author    G. Inesi, M. Kurzmack, D. Kosk-Kosicka, D. Lewis, H. Scofano, H. G. Uim Araes-MottaRequires cookie*
 Title    Equilibrium and Kinetic Studies of Calcium Transport and ATPase Activity in Sarcoplasmic Reticulum  
 Abstract    A number o f equilibrium and kinetic m easurem ents are presented to characterize the partial reactions o f the ATPase and transport cycle in sarcoplasm ic reticulum vesicles. The cycle begins with calcium and nucleotide binding on sites available on the outer surface o f the vesicles. A phosphorylated enzyme intermediate is then formed, and the calcium sites are subjected to a change in their orientation and their affinity for calcium . It is shown that steps involved in cal­ cium release on the inner side o f the vesicles are rate lim iting for the cycle, and are follow ed by hydrolytic cleavage o f the intermediate with release o f inorganic phosphate and recycling o f the enzyme. 
  Reference    Z. Naturforsch. 37c, 685 (1982); received February 6 /M arch 23 1982 
  Published    1982 
  Keywords    Calcium, Transport, ATPase, Sarcoplasm ic Reticulum 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0685.pdf 
 Identifier    ZNC-1982-37c-0685 
 Volume    37 
3Author    Wolfgang Lockau, Susanne PfefferRequires cookie*
 Title    A Cyanobacterial ATPase Distinct from the Coupling Factor of Photophosphorylation  
 Abstract    A particle-bound, M g2+-dependent A TPase activity is investigated in cell-free extracts o f the cyanobacterium Anabaena variabilis. The enzym e can be clearly distinguished from the 
  Reference    Z. Naturforsch. 37c, 658 (1982); received March 231982 
  Published    1982 
  Keywords    Cyanobacterium, Anabaena variabilis, ATPase, Coupling Factor, Cytochrom e Oxidase 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0658.pdf 
 Identifier    ZNC-1982-37c-0658 
 Volume    37 
4Author    Hans Liidi, Wilhelm HasselbachRequires cookie*
 Title    Fluorescence Studies on N-(3-Pyrene)Maleinimide-Labeled Sarcoplasmic Reticulum ATPase in Native and Solubilized Membranes  
 Abstract    Fluorescence polarization and formation of excimers were studied in N-(3-pyrene)malein-imide-labeled sarcoplasmic reticulum vesicles. 1. The polarization of pyrenemaleinimide labeled vesicles does not change with temperature and shows a pronounced decrease at labeling concentrations larger than 1 mol pyrenemaleinimide per 10 mol ATPase. 2. Solubilization of the membrane with myristoylglycerophosphocholine renders the polariza­ tion temperature dependent, but does not affect the concentration dependent depolarization observed in native vesicles. 3. The polarization of labeled vesicles is much smaller than to be expected from the tempera­ ture independent polarization indicating that the pyrenemaleinimide polarization did not monitor the rotation of the entire ATPase. Thus segmental motion occurs. 4. Pyrene excimers are observed at label concentrations larger than 1 mol label per 2.5 mol ATPase. 5. The amount of excimers was critically dependent on added detergents. From the fact that non-solubilizing amounts of myristoylglycerophosphocholine strongly reduced the amount of pyrene excimers it is concluded that in the native sarcoplasmic reticulum vesicles at least two ATPase molecules must be in close contact. 
  Reference    Z. Naturforsch. 37c, 1170 (1982); received August 16 1982 
  Published    1982 
  Keywords    Sarcoplasmic Reticulum, ATPase, Protein-Protein-Interactions, Fluorescence Polarization, Excimer Formation 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1170.pdf 
 Identifier    ZNC-1982-37c-1170 
 Volume    37