Inactive enzyme molecules in aging mice: liver aldolase.

Evidence is presented that there is a considerable accumulation of inactive fructose-1,6-diphosphate aldolase (EC 4.1.2.7) in the liver of senescent mice. Liver aldolase was purified from 3-month-old mice and used to immunize rabbits. It was demonstrated with the monospecific antibody thus produced that the liver aldolase of young adult (3 month) and aged (31 month) mice are antigenically identical. With the antibody, inactive enzyme molecules (crossreacting material) in liver homogenate of old mice were detected. The liver aldolase of senescent mice had half as much active enzyme per mg of protein, as well as per antigenic unit, as did the liver aldolase of young adult mice. The accumulation of faulty enzyme molecules may be one of the causes of debilitation leading to senescence and death.