Augustin W, Gellerich F N
Acta Biol Med Ger. 1981;40(4-5):603-9.
Respiration and phosphorylation in functionally intact isolated reticulocyte mitochondria are controlled by the extramitochondrial ATP/ADP ratio. Mitochondrially bound hexokinase exhibits an apparent preference against mitochondrially formed ATP, as indicated by the lower apparent Km values under phosphorylating conditions. Thereby the control characteristics are shifted to higher ATP/ADP ratios compared to hexokinase free mitochondria. Respiration of intact reticulocytes was estimated to be smaller than had to be expected from the ATP/ADP ratios of total cells roughly corresponding to the cytosolic values. Inhibition of respiration leads to small drop of total adenine nucleotides and lowers the phosphorylation potential directly determined or calculated from metabolite indicators. Compartmentation of ADP by protein binding is discussed as a possible reason for the difference of determined and calculated phosphorylation potentials and the apparent discrepancy between the regulation of mitochondrial ATP-formation in isolated mitochondria and intact reticulocytes.
功能完整的分离网织红细胞线粒体中的呼吸作用和磷酸化作用受线粒体外ATP/ADP比值的控制。线粒体结合型己糖激酶对线粒体生成的ATP表现出明显的偏好，这可由磷酸化条件下较低的表观Km值表明。因此，与无己糖激酶的线粒体相比，控制特性向更高的ATP/ADP比值转移。完整网织红细胞的呼吸作用估计比根据大致对应于胞质值的总细胞ATP/ADP比值所预期的要小。呼吸作用的抑制导致总腺嘌呤核苷酸小幅下降，并降低直接测定或根据代谢物指标计算得出的磷酸化电位。通过蛋白质结合对ADP进行区室化被认为是所测定和计算的磷酸化电位存在差异以及分离线粒体和完整网织红细胞中线粒体ATP生成调节之间明显差异的一个可能原因。
