Diurnal variations in the activities of nucleolar (I) and non-nucleolar (II) DNA-dependent RNA polymerases of rat liver were observed. Both polymerase I and II displayed diphasic shifts in activity levels. However, the patterns of the individual shifts were not synchronous. Polymerase I activity was highest between 0100-1100 hours and lowest between 1700-2000 hours while polymerase II peaks between 2400 and 0500 hours with a low point at 1000 hours. The daily fluctuations and the dissimilar patterns of polymerase I and II activity may be of such significance as to require reevaluation and redesign of studies dealing with regulation of enzyme activity.
|Original language||English (US)|
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - May 26 1972|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology