Desai V G, Weindruch R, Hart R W, Feuers R J
National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
Arch Biochem Biophys. 1996 Sep 1;333(1):145-51. doi: 10.1006/abbi.1996.0375.
Alterations in the mitochondrial electron transport system (ETS) may contribute to aging. Dietary restriction (DR) provides a model to investigate retarded aging. ETS activities were measured in gastrocnemius from 10- and 20-month-old B6C3F1 female mice fed either ad libitum (AL) or DR diets (40% < AL). Older (26 month old) AL mice were studied for complex IV. Activities of complexes I, III, and IV decreased 54-74% from 10 to 20 months of age in AL mice. At 10 months, activities of complexes I, III, and IV were 33-64% lower in DR compared to AL mice. The Km for ubiquinol-2 of complex III increased 29% by 20 months of age in AL mice while no change occurred in DR mice. The Vmax of complex IV declined by 90% from 10 to 26 months of age in AL mice and this change was opposed by DR. Complex IV contains high- and low-affinity binding sites. The Km for high-affinity sites was not influenced by age or diet through 20 months; however, the Km was approximately twofold higher at 26 months in AL mice. The percentage of total binding sites which were of high affinity fell from 68% at 10 months in AL mice to 46% at 20 months and was even lower (33%) at 26 months. This value was 80% for DR mice at 10 and 20 months. These alterations with aging in mitochondrial ETS capacities may contribute to decreases in skeletal muscle function.
线粒体电子传递系统（ETS）的改变可能与衰老有关。饮食限制（DR）提供了一个研究延缓衰老的模型。对自由采食（AL）或DR饮食（摄入量比AL组少40%）的10月龄和20月龄B6C3F1雌性小鼠的腓肠肌进行ETS活性测定。对26月龄的老年AL小鼠进行复合物IV的研究。在AL小鼠中，复合物I、III和IV的活性在10至20月龄时下降了54 - 74%。在10月龄时，DR小鼠中复合物I、III和IV的活性比AL小鼠低33 - 64%。在AL小鼠中，复合物III对泛醇-2的Km值到20月龄时增加了29%，而DR小鼠则无变化。在AL小鼠中，复合物IV的Vmax在10至26月龄时下降了90%，而DR可对抗这种变化。复合物IV包含高亲和力和低亲和力结合位点。到20月龄时，高亲和力位点的Km值不受年龄或饮食的影响；然而，在26月龄时，AL小鼠的Km值约高出两倍。AL小鼠中高亲和力结合位点占总结合位点比例从10月龄时的68%降至20月龄时的46%，在26月龄时更低（33%）。DR小鼠在10月龄和20月龄时该值为80%。线粒体ETS能力随衰老发生的这些改变可能导致骨骼肌功能下降。
