Albin R, Dowell R T, Zak R, Rabinowitz M
Biochem J. 1973 Nov;136(3):629-37. doi: 10.1042/bj1360629.
The accumulation of inner mitochondrial components of rat heart was studied 1 and 3 days after constriction of the ascending aorta of rats. By 1 day after aortic constriction, the activities of three mitochondrial respiratory enzymes/mg of cardiac homogenate protein were increased; after 3 days, specific activities had levelled off or decreased. Selective accumulation of inner mitochondrial membrane components 24h after aortic constriction was further indicated by increased left ventricular cytochrome c concentration (nmol/mg of protein). By 3 days after surgery, cytochrome c concentration was significantly diminished. Low-temperature spectroscopy of isolated mitochondria showed that the ratios of cytochromes c, b and a+a(3) remained unchanged after aortic constriction, suggesting that cytochrome c was a good indicator of the response of the other mitochondrial inner-membrane cytochromes as well. The effect of cardiac hypertrophy on the turnover of cytochrome c was also examined. Cytochrome c was labelled in its haem group with delta-amino[2,3-(3)H(2)]laevulinate 3 days before aortic constriction. By 1 day after surgery the total ventricular radioactivity in cytochrome c of aortic banded animals was significantly higher than in sham-operated controls, indicating a decreased degradation rate in the former during the first postoperative day. delta-Aminolaevulinate was shown to be a particularly suitable precursor for such turnover studies, since it results in rapid pulse-labelling of cytochrome c (peak activity in 90min), is rapidly removed from the precursor pool (t((1/2))=30min) and is not reutilized.
在大鼠升主动脉缩窄术后1天和3天，研究了大鼠心脏线粒体内成分的蓄积情况。主动脉缩窄术后1天，每毫克心脏匀浆蛋白中三种线粒体呼吸酶的活性增加；术后3天，比活性趋于平稳或下降。主动脉缩窄24小时后，左心室细胞色素c浓度（纳摩尔/毫克蛋白）升高，进一步表明线粒体内膜成分有选择性蓄积。术后3天，细胞色素c浓度显著降低。对分离出的线粒体进行低温光谱分析表明，主动脉缩窄后细胞色素c、b和a+a(3)的比例保持不变，这表明细胞色素c也是其他线粒体内膜细胞色素反应的良好指标。还研究了心肌肥大对细胞色素c周转的影响。在主动脉缩窄前3天，用δ-氨基[2,3-(3)H(2)]乙酰丙酸标记细胞色素c的血红素基团。术后1天，主动脉缩窄动物心室细胞色素c中的总放射性显著高于假手术对照组，表明术后第一天前者的降解速率降低。已证明δ-氨基乙酰丙酸是进行此类周转研究的特别合适的前体，因为它能使细胞色素c快速脉冲标记（90分钟达到峰值活性），能从前体池中快速清除（半衰期=30分钟）且不会被再利用。
