大鼠肝脏线粒体中金属卟啉外排的研究。钾离子及其他阳离子的影响。
Studies on the efflux of metalloporphyrin from rat liver mitochondria. Effect of K+ and other cations.
作者信息
Husby P, Romslo I
出版信息
Biochem J. 1981 May 15;196(2):451-7. doi: 10.1042/bj1960451.
The mechanism by which metalloporphyrins synthesized within the mitochondria escape to the incubation medium was studied in isolated rat liver mitochondria. In a low-ionic-strength sucrose medium, the efflux of metalloporphyrins is markedly decreased when K+ (greater than 10 mM) is added. The effect of K+ is not dependent on the energy state of the mitochondria and it can in part be abolished by adding globin, but not albumin. K+ also decreases the uptake of porphyrins by the mitochondria and thereby the rate of synthesis of metalloporphyrins. Qualitatively similar results are found with Na+, Li+, Mg2+ and Ca2+. Quantitatively, however, the efficiency of cations to inhibit the release of metalloporphyrins decreases in the order: Mg2+ greater than Ca2+ greater than K+ greater than Li+ greater than Na+. Co-protoporhyrin behaves essentially as Co-deuteroporphyrin. The results provide further evidence that the efflux of metalloporphyrins from the mitochondria depends on haem-binding ligands of the suspending medium and also on the ionic strength of the incubation medium.
在分离的大鼠肝线粒体中研究了线粒体内合成的金属卟啉逃逸到孵育介质中的机制。在低离子强度的蔗糖介质中，当加入K⁺（大于10 mM）时，金属卟啉的流出显著减少。K⁺的作用不依赖于线粒体的能量状态，并且通过加入球蛋白而非白蛋白可部分消除该作用。K⁺还减少线粒体对卟啉的摄取，从而降低金属卟啉的合成速率。Na⁺、Li⁺、Mg²⁺和Ca²⁺也得到了定性相似的结果。然而，从数量上看，阳离子抑制金属卟啉释放的效率顺序为：Mg²⁺＞Ca²⁺＞K⁺＞Li⁺＞Na⁺。辅酶原卟啉的行为与辅氘卟啉基本相同。这些结果进一步证明，金属卟啉从线粒体的流出取决于悬浮介质中的血红素结合配体以及孵育介质的离子强度。
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