Table 1.

Age-Related Changes in Proteasome Activities in the Spleen

	3 Month	25 Month	25 Month
	AL	AL	DR
Chymotrypsin	107 ±34	225 ±60*	236± 54*
Trypsin	72 ±14	89±11	101 ±19
Post-Glutamyl Peptidase	251 ±25	263 ±23	297 ±27

All proteasome activities are reported as the mean and standard deviation for the arbitrary fluorescence units following a 2 hour analysis of proteasome peptidase activities in the different spleen lysates Each of the values have had the background fluorescence subtracted, by incubating additional spleen lysates with the proteasome inhibitor MG132 (5 μM) for 30 minutes prior to the addition of individual fluorogenic substrate. See methods for details. AL= ad libitum, DR = dietary restriction.

^*p < 0.05 compared to 3 month old AL spleen