Dephosphorylation of the phosphorylated elongation factor-2 in the livers of calorie-restricted and freely-fed rats during ageing.
Slowing down of the rate of protein synthesis during ageing is accompanied by alterations in the amounts and activities of elongation factors, eEF-1 and eEF-2. Since the activity of eEF-2 is regulated by phosphorylation, we have determined the changes in the activities of eEF-2-specific phosphorylating and dephosphorylating enzymes during ageing. Previously, we have reported an age-related increase in the activity of eEF-2 kinase (BBRC, 192, 1210, 1993). We have now compared the activities of a dephosphorylating enzyme protein phosphatase 2A (PP2A) in young and old liver extracts from freely-fed or calorie-restricted rats. The activity of PP2A remain unaltered during ageing. Furthermore, there was no change in the kinetics and extent of PP2A-dependent and PP2A-independent dephosphorylation of eEF-2 during ageing.
Riis
B
B
Wenner-Gren Institute, Department of Zoological Cell Biology, Stockholm University, Sweden.
Rattan
S I
SI
Palmquist
K
K
Clark
B F
BF
Nygård
O
O
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002457:Cell Extracts / Q000502:physiology; D002149:Energy Intake / Q000502:physiology*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D051381:Rats; D011916:Rats, Inbred F344
D002457:Cell Extracts; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D010750:Phosphoproteins; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2