Adjustment of K' for the creatine kinase, adenylate kinase and ATP hydrolysis equilibria to varying temperature and ionic strength.

Adjustment of K' to varying pH and pMg for the creatine kinase, adenylate kinase and ATP hydrolysis equilibria permitting quantitative bioenergetic assessment.

Physiologists and biochemists frequently ignore the importance of adjusting equilibrium constants to the ionic conditions of the cell prior to calculating a number of bioenergetic and kinetic parameters. The present study examines the effect of pH and free magnesium levels (free [Mg2+]) on the apparent equilibrium constants (K') of creatine kinase (ATP: creatine N-phosphotransferase; EC 2.7.3.2...

The Effect of Cigarette Smoking on Human Sperm Creatine Kinase Activity: As An ATP Buffering System in Sperm

Effect of temperature on the creatine kinase equilibrium.

The effect of temperature on the apparent equilibrium constant of creatine kinase (ATP:creatine N-phosphotransferase (EC 2.7.3.2)) was determined. At equilibrium the apparent K' for the biochemical reaction was defined as [formula: see text] The symbol sigma denotes the sum of all the ionic and metal complex species of the reactant components in M. The K' at pH 7.0, 1.0 mM free Mg2+, and ionic ...

Phosphoryl Group Exchange between ATP and ADP Catalyzed by H+-ATPase from Oat Roots.

ATP-ADP exchange was estimated in the presence of plasma membrane H+-ATPase of oat (Avena sativa) roots partially purified with Triton X-100 by measuring [14C]ATP formation from [14C]ADP. Most studies were done at 0[deg]C. At pH 6.0 the exchange showed: (a) Mg2+ requirement with a biphasic response giving maximal activity at 152 [mu]M and (b) insensitivity to ionic strength, [Na+], and [K+]. AT...

The Eq+librium Constants of the Adenosine Triphosphate Hydrolysis and the Adenosine Triphosphate- Citrate Lyase Reactions

The observed standard free energy change (AGibs) for the hydrolysis of the terminal pyrophosphate bond of ATP has been experimentally determined under physiological conditions using an entirely new set of reactions. The observed equilibrium constant (K,,bs) for the combined reactions of acetate kinase (EC 2.7.2.1) and phosphate acetyltransferase (EC 2.3.1.8) has been determined at 38”, pH 7.0, ...