Factors affecting the kinetics and equilibrium of exchange reactions of the citrate-transporting system of rat liver mitochondria.
Factors affecting the kinetics and equilibrium of exchange reactions of the citrate-transporting system of rat liver mitochondria.
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DOI：
10.1016/s0021-9258(18)61904-0
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发表时间：
1971-09
期刊：
影响因子：
--
通讯作者：
B. Robinson;G. R. Williams;M. Halperin;C. Leznoff
中科院分区：
文献类型：
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作者：
B. Robinson;G. R. Williams;M. Halperin;C. Leznoff
苯1，2，3-三羧酸被发现是一种足够有效的柠檬酸盐转运的抑制剂，通过大鼠肝线粒体，它可以用于“抑制剂停止”实验。因此，它是可以测量的柠檬酸盐运输系统催化的交换反应的初始速率，并研究温度和柠檬酸盐，苹果酸盐和Mg 2+的浓度的速率的依赖性。与线粒体内[14 C]柠檬酸盐的交换速率和程度均小于柠檬酸盐与线粒体内[14 C]柠檬酸盐的交换速率和程度。两种交换之间的速率和程度差异被认为是由于l-苹果酸-[14 C]柠檬酸交换导致线粒体膜上电荷或pH不平衡。有人提出，苹果酸2-交换柠檬酸2-，而不是柠檬酸3-，从而建立一个pH值的差异，限制进一步的交换。
Benzene 1,2,3-tricarboxylic acid was found to be a sufficiently potent inhibitor of citrate transport by rat liver mitochondria that it may be used in "inhibitor stop" experiments. It was thus possible to measure the initial rates of exchange reactions catalyzed by the citrate-transporting system and to study the dependence of the rate on temperature and the concentrations of citrate, malate, and Mg2+. Both the rate and extent of exchange ofl-malate with intramitochondrial [14C]citrate were less than that of citrate with intramitochondrial [14C]citrate. This difference in the rate and extent between the two exchanges was thought to be due to the fact thatl-malate-[14C]citrate exchange resulted in a disequilibrium of either charge or pH across the mitochondrial membrane. It is proposed that malate2-exchanges for citrate2-rather than citrate3-, thereby setting up a pH differential which restricts further exchange.