Reznick A Z, Gershon D
Mech Ageing Dev. 1979 Dec;11(5-6):403-15. doi: 10.1016/0047-6374(79)90016-2.
The administration of 0.2% of the amino acid analogues canavanine and 6-fluorotryptophan to young nematode cultures caused the appearance of inactive but antigenically reactive aldolase molecules at levels comparable to those found in old untreated cultures. Concomitant with the rapid appearance of inactive enzyme molecules a rapid rate of mortality could be detected. Mortality, however, ceased when a massive disappearance of inactive molecules could be observed. Subsequently, mortality resumed at a rate similar to that found in untreated cultures. The NaH14CO3 method of Swick and Ip (J. Biol. Chem., 249 (1974) 6836-6841) was used to estimate the half-life of proteins. The half-life of total soluble proteins in old and intermediate age animals was 4 times and 2.5 times longer, respectively, than that of young nematodes. No differences could be discerned in the half-lives of total proteins between analogue-treated and control animals of young and intermediate ages. However, the rate of disposal of inactive molecules was slower in intermediate age as compared to young animals as it was closely related to the general rate of protein degradation in the different age groups. The results suggest that (a) the proportion of inactive enzyme molecules encountered in old animals is potentially detrimental, (b) the decline in efficiency of the degradation system in older animals may account for the accumulation of altered protein molecules in aging organisms.
向年轻线虫培养物中施用0.2%的氨基酸类似物刀豆氨酸和6-氟色氨酸，导致出现无活性但具有抗原反应性的醛缩酶分子，其水平与未处理的老龄培养物中的水平相当。伴随着无活性酶分子的快速出现，可以检测到快速的死亡率。然而，当观察到无活性分子大量消失时，死亡率停止。随后，死亡率以与未处理培养物中相似的速率恢复。采用Swick和Ip的NaH14CO3方法（《生物化学杂志》，249(1974)6836 - 6841）来估计蛋白质的半衰期。老龄和中年动物中总可溶性蛋白质的半衰期分别比年轻线虫长4倍和2.5倍。在年轻和中年的经类似物处理的动物与对照动物之间，总蛋白质的半衰期没有差异。然而，与年轻动物相比，中年动物中无活性分子的清除速率较慢，因为它与不同年龄组中蛋白质降解的总体速率密切相关。结果表明：(a)老龄动物中遇到的无活性酶分子比例可能有害；(b)老龄动物中降解系统效率的下降可能解释了衰老生物体中改变的蛋白质分子的积累。
