Kinetic and thermodynamic control of ATP synthesis by sarcoplasmic reticulum adenosinetriphosphatase.
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چکیده
منابع مشابه
Kinetic and thermodynamic control of ATP synthesis by sarcoplasmic reticulum adenosinetriphosphatase.
Several experimental parameters, critical to the analysis of ATP synthesis by sarcoplasmic reticulum ATPase, were determined experimentally. 1) The phosphorylated enzyme intermediate obtained with acetylphosphate in the presence of a Ca2+ gradient was shown to be entirely ADP sensitive but quite stable in the absence of added ADP. On the contrary, the phosphoenzyme obtained with ATP is unstable...
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Phosphorylation of sarcoplasmic reticulum ATPase with Pi and phosphoryl transfer from the phosphoenzyme to ADP to form ATP were studied in experiments including two sequential steps in the absence of a transmembrane Ca2+ gradient. This was accomplished with a variety of experimental manipulations including jumps of Ca2+ concentrations, pH, temperature, and water activity. Phosphorylation with ...
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The sarcoplasmic reticulum of skeletal muscle retains a membrane bound Ca2+-ATPase which is able to interconvert different forms of energy. A part of the chemical energy released during ATP hydrolysis is converted into heat and in the bibliography it is assumed that the amount of heat produced during the hydrolysis of an ATP molecule is always the same, as if the energy released during ATP clea...
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Incorporation of Pi and ATP synthesis by sarcoplasmic reticulum ATPase were studied by rapid quench methods in order to demonstrate whether protein phosphorylation obtained in various experimental conditions leads to intermediates of the same reaction chain, or to products of independent reactions. Phosphorylation occurs rapidly (k = 30 s-‘) when saturating Pi is added to vesicles preincubated ...
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Magnesium transport across sarcoplasmic reticulum (SR) vesicles was investigated in reaction mixtures of various composition using antipyrylazo III or arsenazo I to monitor extravesicular free Mg2+. The half-time of passive Mg2+ efflux from Mg2+-loaded SR was 100 s in 100 mM KCl, 150 S in 100 mM K gluconate, and 370 S in either 100 mM Tris methanesulfonate or 200 mM sucrose solutions. The conce...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1987
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)45166-6