Related Experiment Video
Updated: Jul 13, 2026

Isolation of Intermediate Filament Proteins from Multiple Mouse Tissues to Study Aging-associated Post-translational Modifications
Published on: May 18, 2017
Protein phosphotransferases from liver of ageing rats
Abstract:
Cyclic AMP-dependent and -independent protein kinase have been isolated from livers of rats at 3, 9, 18 and 30 months of age. A preliminary characterization reported here reveals that in addition to a decrease in their activities due to ageing and a likely shift to cyclic AMP-independent casein kinase activity at 30 months of age, the enzymes show modest changes in some of their kinetic properties. In the case of cyclic AMP-dependent enzymes, decreases in Vmax for ATP and Km for cyclic AMP as well as histones were observed. On the contrary, casein kinases displayed increases in Km values for casein, GTP and ATP. Molecular weights of 143,000 daltons for casein kinases from 3-, 9- and 18-month-old rats and 211,000 daltons for that from 30-month-old rats were obtained. Slight differences were also noticed in the inhibitor sensitivity (NaF and 2,3-diphosphoglyceric acid) of casein kinases isolated from rats of different ages.
Related Concept Videos
Phosphorylation
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Effect of Hepatic Disease on Pharmacokinetics: Pathophysiologic Assessment and Liver Function Test

