Jones D P
Am J Physiol. 1986 May;250(5 Pt 1):C663-75. doi: 10.1152/ajpcell.1986.250.5.C663.
Endogenous enzymes with different subcellular localizations provide in situ probes to study O2 and ATP concentration at various sites within cells. Results from this approach indicate that substantial intracellular concentration gradients occur under some O2- and ATP-limited conditions. These studies, along with electron microscopic analyses and mathematical modeling, indicate that clustering and distribution of mitochondria are major factors in determining the magnitude and location of the concentration gradients. The mitochondria appear to be clustered in sites of high ATP demand to maximize ATP supply under conditions of limited production. The size of such clusters is limited by the magnitude of the O2 gradient needed to provide adequate O2 concentrations for mitochondrial function within the clusters. Thus microheterogeneity of metabolite concentrations can occur in cells without membranal compartmentation and may be important in determining the rates of various high-flux processes.
具有不同亚细胞定位的内源性酶提供了原位探针，用于研究细胞内各个位点的氧气和ATP浓度。该方法的结果表明，在某些氧气和ATP受限的条件下，细胞内会出现显著的浓度梯度。这些研究，连同电子显微镜分析和数学建模，表明线粒体的聚集和分布是决定浓度梯度大小和位置的主要因素。线粒体似乎聚集在ATP需求高的部位，以便在产量有限的情况下最大限度地供应ATP。这种聚集的大小受到为簇内线粒体功能提供足够氧气浓度所需的氧气梯度大小的限制。因此，代谢物浓度的微观异质性可以在没有膜分隔的细胞中发生，并且可能在决定各种高通量过程的速率方面很重要。
