期刊
BIOCHEMISTRY
卷 52, 期 16, 页码 2793-2809出版社
AMER CHEMICAL SOC
DOI: 10.1021/bi3015983
关键词
-
资金
- Division of Intramural Research, National Heart, Lung and Blood Institute
Calcium is believed to regulate mitochondrial oxidative phosphorylation, thereby contributing to the maintenance of cellular energy homeostasis. Skeletal muscle, with an energy conversion dynamic range of up to 100-fold, is an extreme case for evaluating the cellular balance of ATP production and consumption. This study examined the role of Ca2+ in the entire oxidative phosphorylation reaction network in isolated skeletal muscle mitochondria and attempted to extrapolate these results back to the muscle, in vivo. Kinetic analysis was conducted to evaluate the dose-response effect of Ca2+ on the maximal velocity of oxidative phosphorylation (V-maxO) and the ADP affinity. Force-flow analysis evaluated the interplay between energetic driving forces and flux to determine the conductance, or effective activity, of individual steps within oxidative phosphorylation. Measured driving forces [extramitochondrial phosphorylation potential (Delta G(ATP)), membrane potential, and redox states of NADH and cytochromes b(H), b(1), c(1), c, and a,a(3)] were compared with flux (oxygen consumption) at 37 degrees C; 840 nM Ca2+ generated an similar to 2-fold increase in V-maxO with no change in ADP affinity (similar to 43 mu M). Force flow analysis revealed that Ca2+ activation of V-maxO was distributed throughout the oxidative phosphorylation reaction sequence. Specifically, Ca2+ increased the conductance of Complex IV (2.3-fold), Complexes I and III (2.2-fold), ATP production/transport (24 fold), and fuel transport/dehydrogenases (1.7-fold). These data support the notion that Ca2+ activates the entire muscle oxidative phosphorylation cascade, while extrapolation of these data to the exercising muscle predicts a significant role of Ca2+ in maintaining cellular energy homeostasis.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据