Yarian Connie S, Sohal Rajindar S
Department of Molecular Pharmacology and Toxicology, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA.
J Bioenerg Biomembr. 2005 Apr;37(2):91-6. doi: 10.1007/s10863-005-4132-z.
The main objective of this study was to determine if the activities of the mitochondrial citric acid cycle enzymes are altered during the normal aging process. Flight muscle mitochondria of houseflies of different ages were used as a model system because of their apparent age-related decline in bioenergetic efficiency, evident as a failure of flying ability. The maximal activities of each of the citric acid cycle enzymes were determined in preparations of mitochondria from flies of relatively young, middle, and old age. Aconitase was the only enzyme exhibiting altered activity during aging. The maximal activity of aconitase from old flies was decreased by 44% compared to that from young flies while the other citric acid cycle enzymes showed no change in activity with age. It is suggested that the selective age-related decrease in aconitase activity is likely to contribute to a decline in the efficiency of mitochondrial bioenergetics, as well as result in secondary effects associated with accumulation of citrate and redox-active iron.
本研究的主要目的是确定线粒体柠檬酸循环酶的活性在正常衰老过程中是否发生改变。由于不同年龄家蝇飞行肌线粒体的生物能量效率明显随年龄下降，表现为飞行能力丧失，因此将其用作模型系统。分别测定了相对年轻、中年和老年家蝇线粒体中各柠檬酸循环酶的最大活性。乌头酸酶是衰老过程中唯一活性发生改变的酶。与年轻家蝇相比，老年家蝇乌头酸酶的最大活性降低了44%，而其他柠檬酸循环酶的活性并未随年龄变化。研究表明，乌头酸酶活性随年龄选择性降低可能导致线粒体生物能量学效率下降，并引发与柠檬酸和氧化还原活性铁积累相关的继发效应。
