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The ATP/ADP exchange is shown to be a partial reaction of the (H+ +K+)-ATPase by the absence of measurable nucleoside diphosphokinase activity and the insensitivity of the reaction to P1, P5-di(adenosine-5') pentaphosphate, a myokinase inhibitor. The exchange demonstrates an absolute requirement for Mg2+ and is optimal at an ADP/ATP ratio of 2. The high ATP concentration (K0.5=116 microM) required for maximal exchange is interpreted as evidence for the involvement of a low affinity form of nucleotide site. The ATP/ADP exchange is regarded as evidence for an ADP-sensitive form of the phosphoenzyme. In native enzyme, pre-steady state kinetics show that the formation of the phosphoenzyme is partially sensitive to ADP while modification of the enzyme by pretreatment with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) in the absence of Mg2+ results in a steady-state phosphoenzyme population, a component of which is ADP sensitive. The ATP/ADP exchange reaction can be either stimulated or inhibited by the presence of K+ as a function of pH and Mg2+.
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
April 1967,
Archives of biochemistry and biophysics,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
January 1981,
The Journal of membrane biology,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
September 1977,
Biochimica et biophysica acta,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
September 1976,
Biochimica et biophysica acta,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
November 2006,
Biochemistry. Biokhimiia,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
January 1970,
Biochimica et biophysica acta,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
January 1987,
The American journal of physiology,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
June 1982,
Biochimica et biophysica acta,
E Rabon, and
G Sachs, and
S Mårdh, and
B Wallmark
May 1990,
Seikagaku. The Journal of Japanese Biochemical Society,
