The diurnal variation of hepatic HMG-CoA reductase activity is due to changes in the level of immunoreactive protein.
The diurnal variation in levels of hepatic HMG-CoA reductase immunoreactive protein and enzyme activity were determined in rats. Immunoreactive protein levels changed together with enzyme activity. Thus the catalytic efficiency of HMG-CoA reductase was not significantly changed. The data suggest that the diurnal variation in hepatic HMG-CoA reductase activity is due to changes in enzyme protein levels rather than changes in phosphorylation state of the enzyme, for example, which would cause changes in catalytic efficiency.
Ness
G C
GC
Department of Biochemistry and Molecular Biology, College of Medicine, University of South Florida, Tampa, 33612, USA.
Chambers
C M
CM
D000818:Animals; D002940:Circadian Rhythm; D003624:Darkness; D006903:Hydroxymethylglutaryl CoA Reductases / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D015151:Immunoblotting / Q000379:methods; D007700:Kinetics; D008027:Light; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D006903:Hydroxymethylglutaryl CoA Reductases