Gerencser G A
Department of Physiology, JHMHC, University of Florida, Gainesville 32610-0274.
FEBS Lett. 1993 Oct 25;333(1-2):137-40. doi: 10.1016/0014-5793(93)80391-7.
It has been determined that Mg2+ stimulates phosphorylation while Cl- stimulates dephosphorylation of the chloride pump during its reaction sequence. The stoichiometry of ATP hydrolyzed to Cl- transported during a single cycle of the reaction sequence was ascertained. Intracellular concentrations of ATP, ADP and inorganic phosphate were determined and, coupled with an estimate of the standard free energy of hydrolysis for ATP, the operant free energy for ATP hydrolysis was calculated. Because the operating free energy of the pump is approximately one-half the energy obtained from the total free energy of ATP hydrolysis, the only possible integral stoichiometries are one or, at the most, two net charges transported per cycle per ATP hydrolyzed.
已经确定，在氯化物泵的反应序列中，Mg2+ 刺激磷酸化，而 Cl- 刺激去磷酸化。确定了在反应序列的单个循环中水解的 ATP 与转运的 Cl- 的化学计量关系。测定了细胞内 ATP、ADP 和无机磷酸盐的浓度，并结合 ATP 水解标准自由能的估计值，计算了 ATP 水解的有效自由能。由于泵的操作自由能约为 ATP 水解总自由能的一半，所以每个 ATP 水解循环中唯一可能的整数化学计量是每个循环转运一个或最多两个净电荷。
