Calorie restriction (R), the only known method to delay the aging process and extend mean and maximal lifespan, has been shown to delay the age-related decline in protein degradation. There are several proteolytic pathways. The ubiquitin- and @entity855 -dependent proteolytic pathway (UPP) is frequently associated with degradation of damaged abnormal and/or regulatory proteins. We examined the effect of aging and R on supernatants of livers taken from young (4.5 months) and old (23 months) Emory @entity19 . Aging was associated with increased levels of endogenous ubiquitin conjugates, enhanced ability to form high molecular weight conjugates and ubiquitin activating @entity13651 and ubiquitin conjugating @entity57367 activity in the control (C) liver supernatants. The age-related increase in levels of endogenous ubiquitin conjugates in liver appears to be primarily due to increased @entity69558 activities. R prevented the age-related increase in @entity69558 activity, and thus prevented the age-related increase in levels of ubiquitin conjugates. In spite of the age-related increase in ubiquitin conjugates, no age-related changes in ubiquitin-dependent proteolytic pathway were observed in the C animals. R was associated with an enhanced ability (130%) to degrade beta-lactoglobulin by the ubiquitin-dependent proteolytic pathway in livers from 4.5-month-old animals relative to age-matched C livers. However, rates of the ubiquitin-dependent degradation of beta-lactoglobulin in the 23-month-old C and R animals were indistinguishable. There were no age- or diet-related differences in the ability to degrade another substrate, oxidized ribonuclease (RNase).

Aging, calorie restriction and ubiquitin-dependent proteolysis in the livers of Emory XXXX .

@entity19 :: ('10090', 'Species') :: ['mice'] @entity57367 :: ('11973(Tax:10090)', 'Gene') :: ['(E2)'] @entity69558 :: ('114689;11973', 'Gene') :: ['E1 and E2'] @entity13651 :: ('114689(Tax:10090)', 'Gene') :: ['(E1)'] @entity855 :: ('MESH:D000255', 'Chemical') :: ['ATP']
@entity19 :: (10090,Species) :: ['mice']
