Proteolysis, caloric restriction and aging

The nature of the aging process has been the subject of considerable specul ation. It is believed that free radical damage to cellular components is on e of the main contributors to the aging process. Studies on proteins have s hown age-related decline in enzyme activities, age-related accumulation of oxidized proteins and a decline of the proteolytic machinery of the cell. T he proteasome, a highly regulated intracellular proteolytic system, is the major enzymatic system responsible for the degradation of damaged proteins. The current knowledge on regulation and of the properties of this unique p roteolytic system with special emphasis to the aging process are discussed in this review. Since it is known that caloric restriction (CR) is the only method to delay the aging process and extend the maximal lifespan the effe cts of CR on the age-related decline in protein degradation is highlighted. (C) 2001 Published by Elsevier Science Ireland Ltd.