The binding of ATP to the catalytic and the regulatory site of Ca2+, Mg2+-dependent ATPase of the sarcoplasmic reticulum. 1982

Y Nakamura, and Y Tonomura

Two kinds of ATP binding sites were found on the ATPase molecule in deoxycholic acid-treated sarcoplasmic reticulum. One was the catalytic site (1 mol/mol active site) and its affinity was high. Upon addition of Ca2+, all the ATP bound to the catalytic site disappeared at 75 mM KCl, while a significant amount of ATP remained bound to the site at 0-2 mM KCl. The latter binding was found to be due to the formation of a slowly exchanging enzyme--ATP complex, which is in equilibrium with phosphoenzyme + ADP. The other binding site was the regulatory one (1 mol/mol active site) and its affinity was low, changing only insignificantly upon addition of Ca2+. The ATP binding to the regulatory site shifted the equilibrium between the slowly exchanging complex and EP toward EP.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D011189 Potassium Chloride A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA. Slow-K,Chloride, Potassium
D000252 Calcium-Transporting ATPases Cation-transporting proteins that utilize the energy of ATP hydrolysis for the transport of CALCIUM. They differ from CALCIUM CHANNELS which allow calcium to pass through a membrane without the use of energy. ATPase, Calcium,Adenosinetriphosphatase, Calcium,Ca(2+)-Transporting ATPase,Calcium ATPase,Calcium Adenosinetriphosphatase,Adenosine Triphosphatase, Calcium,Ca2+ ATPase,Calcium-ATPase,ATPase, Ca2+,ATPases, Calcium-Transporting,Calcium Adenosine Triphosphatase,Calcium Transporting ATPases,Triphosphatase, Calcium Adenosine
D000255 Adenosine Triphosphate An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter. ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D012519 Sarcoplasmic Reticulum A network of tubules and sacs in the cytoplasm of SKELETAL MUSCLE FIBERS that assist with muscle contraction and relaxation by releasing and storing calcium ions. Reticulum, Sarcoplasmic,Reticulums, Sarcoplasmic,Sarcoplasmic Reticulums
D017301 Ca(2+) Mg(2+)-ATPase An enzyme that catalyzes the hydrolysis of ATP and is activated by millimolar concentrations of either Ca(2+) or Mg(2+). Unlike CA(2+)-TRANSPORTING ATPASE it does not require the second divalent cation for its activity, and is not sensitive to orthovanadate. (Prog Biophys Mol Biol 1988;52(1):1). A subgroup of EC 3.6.1.3. ATPase, Calcium Magnesium,ATPase, Magnesium,Adenosinetriphosphatase, Calcium, Magnesium,Adenosinetriphosphatase, Magnesium,Calcium Magnesium ATPase,Calcium Magnesium Adenosinetriphosphatase,Magnesium ATPase,Magnesium Adenosinetriphosphatase,Adenosine Triphosphatase, Calcium, Magnesium,Adenosine Triphosphatase, Magnesium,Ca Mg-ATPase,Ca2+-Mg2+ ATPase,Calcium Magnesium Adenosine Triphosphatase,Mg2+-ATPase,Mg2+-Dependent ATPase,ATPase, Ca2+-Mg2+,ATPase, Mg2+-Dependent,Adenosinetriphosphatase, Calcium Magnesium,Ca Mg ATPase,Ca2+ Mg2+ ATPase,Magnesium Adenosine Triphosphatase,Mg2+ ATPase,Mg2+ Dependent ATPase
D066298 In Vitro Techniques Methods to study reactions or processes taking place in an artificial environment outside the living organism. In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In

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