Kongas Olav, Wagner Marijke J, ter Veld Frank, Nicolay Klaas, van Beek Johannes H G M, Krab Klaas
Department of Mechanics and Applied Mathematics, Institute of Cybernetics, Tallinn Technical University, Akadeemia 21, 12618 Tallinn, Estonia.
Pflugers Arch. 2004 Mar;447(6):840-4. doi: 10.1007/s00424-003-1214-9. Epub 2004 Jan 14.
The response of mitochondrial oxygen consumption to ADP in saponin-skinned cardiac fibre bundles has an apparent Km an order of magnitude higher than that in isolated mitochondria. Here we report that incubating skinned cardiac fibre bundles from wild-type mice or double-knockout mice lacking both cytosolic and mitochondrial creatine kinase (CK) with CK and creatine or with yeast hexokinase and glucose as extramitochondrial ADP-producing systems decreases the apparent Km of the bundles for ADP severalfold. We conclude that the affinity of mitochondria for ADP in mouse heart is of the same order of magnitude as that of isolated mitochondria, while the high apparent Km of the bundles is caused by diffusion gradients outside the mitochondria.
皂素透皮处理的心脏纤维束中线粒体氧消耗对二磷酸腺苷（ADP）的反应，其表观米氏常数（Km）比分离的线粒体中的表观米氏常数高一个数量级。在此我们报告，用肌酸激酶（CK）和肌酸或用酵母己糖激酶和葡萄糖作为线粒体外ADP生成系统，孵育来自野生型小鼠或缺乏胞质和线粒体肌酸激酶（CK）的双敲除小鼠的透皮处理心脏纤维束，可使纤维束对ADP的表观Km降低数倍。我们得出结论，小鼠心脏中线粒体对ADP的亲和力与分离的线粒体中的亲和力处于同一数量级，而纤维束的高表观Km是由线粒体外的扩散梯度引起的。
