Soboll S, Conrad A, Hebisch S
Institut für Physiologische Chemie I, Universität Düsseldorf, Germany.
Mol Cell Biochem. 1994 Apr-May;133-134:105-13. doi: 10.1007/BF01267950.
The influence of mitochondrial creatine kinase on subcellular high energy systems has been investigated using isolated rat heart mitochondria, mitoplasts and intact heart and skeletal muscle tissue. In isolated mitochondria, the creatine kinase is functionally coupled to oxidative phosphorylation at active respiratory chain, so that it catalyses the formation of creatine phosphate against its thermodynamic equilibrium. Therefore the mass action ratio is shifted from the equilibrium ratio to lower values. At inhibited respiration, it is close to the equilibrium value, irrespective of the mechanism of the inhibition. The same results were obtained for mitoplasts under conditions where the mitochondrial creatine kinase is still associated with the inner membrane. In intact tissue increasing amounts of creatine phosphate are found in the mitochondrial compartment when respiration and/or muscle work are increased. It is suggested that at high rates of oxidative phosphorylation creatine phosphate is accumulated in the intermembrane space due to the high activity of mitochondrial creatine kinase and the restricted permeability of reactants into the extramitochondrial space. A certain amount of this creatine phosphate 'leaks' into the mitochondrial matrix. This leak is confirmed in isolated rat heart mitochondria where creatine phosphate is taken up when it is generated by the mitochondrial creatine kinase reaction. At inhibited creatine kinase, external creatine phosphate is not taken up. Likewise, mitoplasts only take up creatine phosphate when creatine kinase is still associated with the inner membrane. Both findings indicate that uptake is dependent on the functional active creatine kinase coupled to oxidative phosphorylation. Creatine phosphate uptake into mitochondria is inhibited with carboxyatractyloside.(ABSTRACT TRUNCATED AT 250 WORDS)
利用分离的大鼠心脏线粒体、线粒体质和完整的心脏及骨骼肌组织，研究了线粒体肌酸激酶对亚细胞高能系统的影响。在分离的线粒体中，肌酸激酶在活跃的呼吸链处与氧化磷酸化功能偶联，从而催化磷酸肌酸逆热力学平衡形成。因此，质量作用比从平衡比向更低值移动。在呼吸受抑制时，无论抑制机制如何，其都接近平衡值。在线粒体质中，当线粒体肌酸激酶仍与内膜相关联时，在相同条件下也得到了相同的结果。在完整组织中，当呼吸和/或肌肉活动增加时，线粒体部分中磷酸肌酸的含量会增加。有人提出，在氧化磷酸化速率较高时，由于线粒体肌酸激酶的高活性以及反应物进入线粒体外空间的通透性受限，磷酸肌酸会在线粒体膜间隙中积累。一定量的这种磷酸肌酸“泄漏”到线粒体基质中。这一泄漏在分离的大鼠心脏线粒体中得到证实，当线粒体肌酸激酶反应产生磷酸肌酸时，线粒体可以摄取它。在肌酸激酶受抑制时，外部的磷酸肌酸不会被摄取。同样，只有当肌酸激酶仍与内膜相关联时，线粒体质才会摄取磷酸肌酸。这两个发现都表明摄取依赖于与氧化磷酸化偶联的功能性活性肌酸激酶。用羧基苍术苷可抑制线粒体对磷酸肌酸的摄取。（摘要截选至250词）
