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Biochemical studies on the mechanism of Generation and accumulation of altered enzymes with age

随年龄变化的酶的产生和积累机制的生化研究

基本信息

批准号：
63480467
负责人：
GOTO Sataro
金额：
$ 3.26万
依托单位：
Toho University, School of Pharmaceutical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-63480467/
关键词：
Aging Altered enzyme Protein Degradation 活性酸素肝実質細胞

项目摘要

(1) We performed model experiments where partially purified aminoacyl tRNA synthetases are incubated with active oxygen producing systems. A part of the enzymes was rendered heat-labile, thus mimicking "old" enzymes in terms of heat-inactivation profiles. It is therefore suggested that active oxygens might be involved in the generation of altered proteins.(2) We demonstrated that half-lives of proteins microinjected into mouse hepatocytes in primary culture as well as intracellularly labeled proteins are extended by 50 to 60% in the cells from old animals. It is therefore suggested that accumulation of altered proteins in senescent animals is partly due to decrease in the turnover of proteins.(3) Twenty third month-old mice were subjected to dietary restriction for 2 months, and then proportion of heat-labile enzymes and half-life of proteins were examined. Proportion of heat-labile enzymes was decreased to a level of young animals and so are the half-lives of proteins.Thus it is suggested that anti-aging effect of dietary restriction is at least partly to "rejuvenate" decreased protein metabolism that occur with age.(4) Using anti-ubiquitin antibody we measured amounts of free and conjugated ubiquitin in the brain, liver and kidney of young and old mice. The amount of free ubiquitin in the brain was decreased by about 40% in the old animals but not in the other tissues. Conjugated forms of ubiquitin was increased significantly in the old brains but not in other tissues. The turnover of altered proteins is thus suggested to decrease in the brain of old animals.

(1)我们进行了模型实验，其中部分纯化的氨酰tRNA合成酶与活性氧产生系统一起孵育。一部分酶被赋予热不稳定性，从而模仿“老”酶的热失活方面。因此，它表明，活性氧可能参与了改变蛋白质的产生。(2)我们证明，在原代培养的小鼠肝细胞中显微注射的蛋白质以及细胞内标记的蛋白质的半衰期在老年动物的细胞中延长了50%至60%。因此，这表明，在衰老的动物中，改变的蛋白质的积累部分是由于蛋白质的周转减少。(3)对23月龄的小鼠进行为期2个月的限食，然后检查不耐热酶的比例和蛋白质的半衰期。热不稳定酶的比例降低到年轻动物的水平，蛋白质的半衰期也是如此。因此，这表明，限制饮食的抗衰老作用至少部分是“恢复”随着年龄的增长而发生的蛋白质代谢下降。(4)使用抗泛素抗体，我们测量了年轻和老年小鼠的脑，肝和肾中的游离和结合的泛素的量。在老年动物中，脑中游离泛素的量减少了约40%，但在其他组织中没有减少。泛素的共轭形式在老年人的大脑中显着增加，但在其他组织中没有。因此，在老年动物的大脑中，改变的蛋白质的周转率下降。