Sarkis G J, Ashcom J D, Hawdon J M, Jacobson L A
Department of Biological Sciences, University of Pittsburgh, PA 15260.
Mech Ageing Dev. 1988 Nov 30;45(3):191-201. doi: 10.1016/0047-6374(88)90001-2.
The activities of 3 lysosomal proteases in the nematode Caenorhabditis elegans are markedly lower in older animals. The aspartyl protease cathepsin D declines about 10-fold from day 3 (early adulthood) to day 11 (near the mean lifespan); this reflects a net decline in the amount of cathepsin D antigen. The specific activity of the thiol protease cathepsin Ce1 declines about 2.5-fold over the same period, and the specific activity of the thiol protease cathepsin Ce2 declines about 8-fold. The activity of a new non-lysosomal protease, designated cathepsin CeX, is invariant with age. The data are consistent with the hypothesis that reduced protease activity in older animals may cause a decline in the rate of protein turnover with age, but do not prove this hypothesis.
在线虫秀丽隐杆线虫中，3种溶酶体蛋白酶的活性在老龄动物中显著降低。天冬氨酸蛋白酶组织蛋白酶D从第3天（成年早期）到第11天（接近平均寿命）下降约10倍；这反映了组织蛋白酶D抗原量的净下降。巯基蛋白酶组织蛋白酶Ce1的比活性在同一时期下降约2.5倍，巯基蛋白酶组织蛋白酶Ce2的比活性下降约8倍。一种新的非溶酶体蛋白酶，命名为组织蛋白酶CeX，其活性不随年龄变化。这些数据与老龄动物蛋白酶活性降低可能导致蛋白质更新率随年龄下降的假说一致，但并未证实这一假说。
