Kinetic analysis of the age related differences in glucose-6-phosphatase activity

• Published in: Experimental gerontology 1975, Vol.10 (6), p.319-323
• Main Authors: Grinna, L.S., Barber, A.A.
• Format: Article
• Language: English
• Subjects: Aging; Animals; Enzyme Activation; Glucose-6-Phosphatase - metabolism; Kidney - drug effects; Kidney - enzymology; Kinetics; Male; Microsomes - drug effects; Microsomes - enzymology; Microsomes, Liver - drug effects; Microsomes, Liver - enzymology; Polyethylene Glycols - pharmacology; Quaternary Ammonium Compounds - pharmacology; Rats
• ISSN: 0531-5565; 1873-6815
• DOI: 10.1016/0531-5565(75)90021-2

Kinetic analysis was performed on glucose-6-phosphatase of 6 and 24 month old rat liver and kidney microsomal fractions. In untreated microsomal fractions of old liver the enzyme displayed decrease in V. In untreated microsomal fractions of old kidney and enzyme displayed decrease in V and increase in Km. Triton X-100 and NH 4OH were used to disrupt the membranes and to activate the enzyme. The treatments lowered the Km of the enzyme. The activated enzymes of the young and old liver had similar Km but the old liver still displayed a lower V. The same results were found for the kidney. Kidney membranes were found to contain about 50% latent enzyme activity which was released by the treatments. The liver did not contain latent enzyme activity. The age related reduction in glucose-6-phosphatase activity appears to be due to reduction in the amount of enzyme present in the membranes. The membranes from old animals appear to be more labile to manipulation than the membranes from young animals.