Pre-steady-state studies of the adenosine triphosphatase activity of coupled submitochondrial particles. Regulation by ADP

Biochemistry ◽  
1988 ◽  
Vol 27 (19) ◽  
pp. 7552-7558 ◽  
Author(s):  
Orlando B. Martins ◽  
M. Tuena de Gomez-Puyou ◽  
A. Gomez-Puyou
Keyword(s):  
Steady State ◽  
Adenosine Triphosphatase ◽  
Submitochondrial Particles ◽  
Adenosine Triphosphatase Activity

The Effects of Substrate Concentration on the Mg-Adenosine Triphosphatase Activity of Myosin

1975 ◽  
Vol 53 (12) ◽  
pp. 1282-1287 ◽  
Author(s):  
T. Nihei ◽  
C. A. Filipenko
Keyword(s):  
Steady State ◽  
Substrate Concentration ◽  
Active Sites ◽  
Adenosine Triphosphatase ◽  
Kinetic Studies ◽  
Heavy Meromyosin ◽  
Adenosine Triphosphatase Activity ◽  
Steady State Rate ◽  
State Rate ◽  
Substrate Concentrations

Using myosin, heavy meromyosin, and subfragment-1 the steady state rate of Mg-modified adenosine triphosphatase (Mg-ATPase) was determined over a range of substrate concentrations between 10−8 M and 5 × 10−3 M, at 0.5 M and 0.05 M KCl (pH 7.4 at 20 °C). At the substrate concentrations below 10−5 M, myosin Mg-ATPase was observed to show that two active sites interact, as suggested by the analysis of transient kinetic studies (Walz, F. G., Jr.: J. Theor. Biol. 41, 357–373 (1973)). The increase in the activity at Mg-ATP concentrations higher than 10−4 M corresponds to the binding of Mg-ATP to myosin sites not responsible for the catalytic action. With heavy meromyosin and subfragment-1, the activity was best expressed by the Michaelis equation. With heavy meromyosin, the activation at high ATP concentrations is detectable, though not as pronounced as with myosin, but not with subfragment-1.

scholarly journals The phosphorylation potential generated by respiring bovine heart submitochondrial particles

1977 ◽  
Vol 168 (2) ◽  
pp. 299-303 ◽  
Author(s):  
S J Ferguson ◽  
M C Sorgato
Keyword(s):  
Adenosine Triphosphatase ◽  
Membrane Vesicles ◽  
Submitochondrial Particles ◽  
Phosphorylation Potential ◽  
Adenosine Triphosphatase Activity ◽  
Bovine Heart

A phosphorylation potential deltaGp, where deltaGp = deltaGo' + RT2.303 log ([ATP]/([ADP][Pi])), of approx. 44.3 kJ.mol-1 (10.6 kcal.mol-1) was generated by submitochondrial particles that were oxidizing either NADH or succinate. Addition of adenylyl imidodiphosphate, which should suppress adenosine triphosphatase activity of any uncoupled particles, did not raise the phosphorylation potential. Raising the Pi concentration slightly increased the magnitude of the value for [ATP]/[ADP], but this did not fully compensate for the increased Pi concentration, so that the phosphorylation potential decreased slightly as the Pi concentration was raised. The phosphorylation potential developed by submitochondrial particles is lower than that generated by phosphorylating membrane vesicles from some bacteria, and is also less than that developed externally by mitochondria, but is strikingly close to the phosphorylation potential that is generated internally by mitochondria.

scholarly journals Environmental CO2 Stimulation of Mitochondrial Adenosine Triphosphatase Activity

1963 ◽  
Vol 238 (2) ◽  
pp. 836-842
Author(s):  
D.D. Fanestil ◽  
A Baird Hastings ◽  
Theodore A. Mahowald
Keyword(s):  
Adenosine Triphosphatase ◽  
Adenosine Triphosphatase Activity ◽  
Stimulation Of
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