Martinez-Ramon A, Knecht E, Rubio V, Grisolia S
Instituto de Investigaciones Citológicas de la Caja de Aborros de Valencia, Spain.
J Histochem Cytochem. 1990 Mar;38(3):371-6. doi: 10.1177/38.3.2303702.
Carbamoyl phosphate synthetase I, the most abundant protein of rat liver mitochondria, plays a key role in synthesis of urea. Because aging affects some liver functions, and because there is no information on the levels of carbamoyl phosphate synthetase I during aging, we assayed the activity of this enzyme and determined immunologically the level of carbamoyl phosphate synthetase I in liver homogenates from young (4 months) and old (18 or 26 months) rats. In addition, we used electron microscopic immunogold procedures to locate and measure the amount of the enzyme in the mitochondrial matrix. There is no significant change in enzyme activity or enzyme protein content with age, although there is a higher concentration of the enzyme in the mitochondria (c. 1.5 times greater) from old rats, which is compensated by a decrease in the fractional volume of the mitochondrial compartment during aging.
氨甲酰磷酸合成酶I是大鼠肝脏线粒体中含量最丰富的蛋白质，在尿素合成中起关键作用。由于衰老会影响某些肝脏功能，且目前尚无关于衰老过程中氨甲酰磷酸合成酶I水平的信息，我们测定了该酶的活性，并通过免疫方法测定了年轻（4个月）和年老（18或26个月）大鼠肝脏匀浆中氨甲酰磷酸合成酶I的水平。此外，我们采用电子显微镜免疫金技术来定位并测量线粒体基质中该酶的含量。随着年龄增长，酶活性或酶蛋白含量没有显著变化，尽管老年大鼠线粒体中该酶的浓度较高（约高1.5倍），但衰老过程中线粒体部分的体积分数下降对此起到了补偿作用。
