Paradies G, Papa S
Boll Soc Ital Biol Sper. 1980 Apr 15;56(7):647-53.
The effect of Ca2+ and other cations on the initial rate of pyruvate translocation by rat liver mitochondria has been studied. It has been found that added Ca2+ strongly stimulates the rate of pyruvate uptake by non-respiring mitochondria. Mn2+ and to lesser extent Sr2+ could replace Ca2+ whilst Mg2+ has only little effect. The stimulation of pyruvate uptake by Ca2+ is completely abolished by alpha-cyanocinnamate a specific inhibitor of pyruvate translocation but not by lanthanide which inhibits Ca2+ uptake. Direct measurements of the transmembrane delta pH in mitochondria show no appreciable changes following the addition of Ca2+, this excluding the possibility that the Ca2+ dependent stimulation of pyruvate uptake might be due to an increase of transmembrane delta pH. It is therefore conceivable that the effect of Ca2+ can be ascribed to an interaction of this cation with the translocator on the external of the mitochondrial membrane. Although the data obtained do not warrant postulation of the nature of the calcium induced stimulation of mitochondrial pyruvate transport it is likely that this effect may be of a great importance in the regulation of pyruvate transport and metabolism in mitochondria.
研究了钙离子及其他阳离子对大鼠肝脏线粒体丙酮酸转运初始速率的影响。结果发现，添加的钙离子能强烈刺激非呼吸状态线粒体摄取丙酮酸的速率。锰离子以及程度稍轻的锶离子可以替代钙离子，而镁离子的影响很小。丙酮酸转运的特异性抑制剂α-氰基肉桂酸能完全消除钙离子对丙酮酸摄取的刺激作用，但抑制钙离子摄取的镧系元素却不能。对线粒体跨膜ΔpH的直接测量表明，添加钙离子后没有明显变化，这排除了钙离子依赖性刺激丙酮酸摄取可能是由于跨膜ΔpH升高的可能性。因此可以推测，钙离子的作用可归因于该阳离子与线粒体外膜上转运体的相互作用。尽管所获得的数据不足以假定钙离子诱导的线粒体丙酮酸转运刺激作用的本质，但这种效应可能在调节线粒体丙酮酸转运和代谢中具有重要意义。
