Evolutionary, Kinetic and Thermodynamic Aspects on the Bioenergetics of Inorganic Pyrophosphate (PPi) and Adenosine Triphosphate (ATP)

1996 ◽  
pp. 145-150 ◽  
Author(s):  
Herrick Baltscheffsky ◽  
Margareta Baltscheffsky
Keyword(s):  
Adenosine Triphosphate ◽  
Inorganic Pyrophosphate

scholarly journals THE REACTION BETWEEN ACTOMYOSIN AND ADENOSINE TRIPHOSPHATE

1948 ◽  
Vol 31 (4) ◽  
pp. 361-375 ◽  
Author(s):  
W. F. H. M. Mommaerts
Keyword(s):  
Enzymatic Hydrolysis ◽  
Adenosine Triphosphate ◽  
Adenosine Diphosphate ◽  
Myosin Atpase ◽  
Recovery Effect ◽  
Inorganic Pyrophosphate ◽  
Atp Concentration ◽  
Initial Drop

1. A study is made of the effect of adenosine triphosphate (ATP) upon the viscosity of solutions of actomyosin in 0.5 M KCl. 2. The observed effects are discussed in terms of an initial drop of the viscosity (viscosity response) and its subsequent slow reversal (recovery effect). The latter is ascribed to a decrease in the ATP concentration through enzymatic hydrolysis. 3. The recovery effect is inhibited by Mg, activated by Ca, in accordance with the effect of these ions on the activity of myosin-ATPase. 4. The viscosity response is not inhibited, probably promoted by Mg. It is not promoted, probably inhibited by Ca. 5. The viscosity response is induced not only by ATP, but to a certain extent also by inosinetriphosphate, inorganic triphosphate, and inorganic pyrophosphate, not by adenosine diphosphate or monophosphate. 6. The viscosity response could be obtained with enzymatically inactive myosin. 7. It is concluded that the effect of ATP upon myosin does not depend on its enzymatic hydrolysis.

Effects of adenosine triphosphate and inorganic pyrophosphate on carbon dioxide fixation by isolated spinach chloroplasts

1969 ◽  
Vol 47 (4) ◽  
pp. 443-447 ◽  
Author(s):  
John R. Vose ◽  
Mary Spencer
Keyword(s):  
Carbon Dioxide ◽  
Adenosine Triphosphate ◽  
Carbon Dioxide Fixation ◽  
Enhancement Effect ◽  
Inorganic Pyrophosphate ◽  
Spinach Chloroplasts ◽  
Stimulation Of

The effects of exogenous ATP and inorganic pyrophosphate on CO2 fixation were investigated with preparations of intact spinach chloroplasts. Under illumination, both ATP and inorganic pyrophosphate resulted in an increase in the rate of CO2 fixation. These stimuli were generally equivalent to one another, and the degree of stimulation was dependent upon the age and condition of the chloroplasts used. During a reaction the enhancement effect increased with time; the initial kinetics (72 μmoles CO2 fixed per milligram chlorophyll per hour) were unaffected by either ATP or inorganic pyrophosphate. The stimulation of CO2 fixation by ATP or inorganic pyrophosphate was inhibited by a buffer pH of more than 8.0. Concentrations of exogenous magnesium above 0.25 mM were found to inhibit both the ATP- and inorganic pyrophosphate-induced increases in CO2 fixation. Phloridzin was found to partially inhibit the enhancement of CO2 fixation by ATP and inorganic pyrophosphate.

Sign in / Sign up

Export Citation Format

Share Document