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Updated: Aug 14, 2026

Measuring Diurnal Rhythms in Autophagic and Proteasomal Flux
Published on: September 17, 2019
The diurnal rhythm of liver glycogen phosphorylase: correlating changes in enzyme activity and enzymic protein
Abstract:
The diurnal rhythm of phosphorylase activity in mouse liver extracts was correlated with the 24 h fluctuations in phosphorylase protein. This last measurement was made using rocket immunoelectrophoresis. The peak activity of phosphorylase appeared coincident (at 18:00 h) with the greatest amount of phosphorylase protein detected. Conversely, the lowest activity measured and lowest enzymic protein content both occurred at 02:00 h. Regression analysis revealed a significant positive correlation between enzyme activity and protein. Thus changes in the cellular concentration of this enzyme are implicated in the diurnal rhythm of liver glycogen.
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