scholarly journals Specificity of the effect of dietary cholesterol on rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity (Short Communication)

1975 ◽  
Vol 148 (2) ◽  
pp. 337-339
Author(s):  
Keith W. Gregory ◽  
Roger Booth
Keyword(s):  
Rat Liver ◽  
Short Communication ◽  
Coenzyme A ◽  
Regulatory Mechanism ◽  
Reductase Activity ◽  
Dietary Cholesterol ◽  
Microsomal Enzymes ◽  
Coa Reductase ◽  
Liver Microsomal Enzymes ◽  
Coenzyme A Reductase

Dietary cholesterol lowers the activity of rat liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase without affecting various other liver microsomal enzymes. This is consistent with a specific regulatory mechanism and distinguishes the action of cholesterol on 3-hydroxy-3-methylglutaryl-CoA reductase from that of at least one other stimulus known to affect this enzyme.

scholarly journals A new method for assaying rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity and its application in a study of the effect of dietary cholesterol on this effect of dietary cholesterol on this enzyme

1977 ◽  
Vol 164 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Y A Baqir ◽  
R Booth
Keyword(s):  
Rat Liver ◽  
Cholesterol Ester ◽  
Time Course ◽  
Coenzyme A ◽  
Reductase Activity ◽  
Dietary Cholesterol ◽  
New Method ◽  
Coa Reductase ◽  
Microsomal Cholesterol ◽  
Coenzyme A Reductase

A new method suitable for measuring rat liver 3-hydroxy-3-methylglutaryl-CoA reductase activity is described and its advantages over methods previously available are discussed. An accurate time course was measured for the inhibition of liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase activity by dietary cholesterol; this enzyme was affected 1 1/4 h after the rats began to consume a cholesterol-rich diet. In this experiment there was no correlation between concentrations of microsomal cholesterol ester and the activity of 3-hydroxy-3-methylglutary-CoA reductase.

scholarly journals Activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in brains of adult and 7-day-old rats

1976 ◽  
Vol 154 (2) ◽  
pp. 559-560 ◽  
Author(s):  
M M. Sudjic ◽  
R Booth
Keyword(s):  
Rat Brain ◽  
Coenzyme A ◽  
Reductase Activity ◽  
Cholesterol Biosynthesis ◽  
Adult Brain ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Old Rats ◽  
Coa Reductase ◽  
Coenzyme A Reductase

Rat brain contains 3-hydroxy-3-methylglutaryl-CoA reductase activity, but this enzyme is far more active in 7-day-old brain than in adult brain. This difference may partly explain why cholesterol biosynthesis is more rapid in growing than in adult rat brain.

scholarly journals Characteristics of rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A reductase

1986 ◽  
Vol 233 (1) ◽  
pp. 167-172 ◽  
Author(s):  
G C Ness ◽  
C E Sample ◽  
M Smith ◽  
L C Pendleton ◽  
D C Eichler
Keyword(s):  
Rat Liver ◽  
Coenzyme A ◽  
Rabbit Antiserum ◽  
Single Band ◽  
Coa Reductase ◽  
Coenzyme A Reductase

A procedure for the preparation of rat liver microsomal fractions essentially devoid of contaminating lysosomes is described. When this preparation was examined by immunoblotting with a rabbit antiserum to rat 3-hydroxy-3-methylglutaryl-CoA reductase, a single band corresponding to an Mr of 100000 was observed. No evidence was found for glycosylation of rat liver-3-hydroxy-3-methylglutaryl-CoA reductase. Native rat liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase differs from the purified proteolytically modified species in that it displays allosteric kinetics towards NADPH.

scholarly journals 3-Hydroxy-3-methylglutaryl coenzyme A reductase localization in rat liver peroxisomes and microsomes of control and cholestyramine-treated animals: quantitative biochemical and immunoelectron microscopical analyses.

1986 ◽  
Vol 103 (3) ◽  
pp. 875-886 ◽  
Author(s):  
G A Keller ◽  
M Pazirandeh ◽  
S Krisans
Keyword(s):  
Rat Liver ◽  
Coenzyme A ◽  
Specific Activity ◽  
Reductase Activity ◽  
Cholesterol Biosynthesis ◽  
Normal Liver ◽  
Hmg Coa Reductase ◽  
The Matrix ◽  
Coa Reductase ◽  
Liver Peroxisomes

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a key regulatory enzyme involved in cholesterol biosynthesis, has recently been reported to be present in rat liver peroxisomes (Keller, G.A., M.C. Barton, D.J. Shapiro, and S.J. Singer, 1985, Proc. Natl. Acad. Sci. USA, 82:770-774). Immunoelectron labeling of ultrathin frozen sections of normal liver, using two monoclonal antibodies to purified rat liver microsomal HMG-CoA reductase, indicated that the enzyme is present in the matrix of peroxisomes. This study is a quantitative biochemical and immunoelectron microscopical analysis of HMG-CoA reductase in rat liver peroxisomes and microsomes of normal and cholestyramine-treated animals. Cholestyramine treatment produced a six- to sevenfold increase in the specific activity of peroxisomal HMG-CoA reductase, whereas the microsomal HMG-CoA reductase specific activity increased by about twofold. Using a computer program that calculates optimal linear combinations of marker enzymes, it was determined that between 20 and 30% of the total reductase activity was located in the peroxisomes of cholestyramine-treated animals. Less than 5% of the reductase activity was present in peroxisomes under control conditions. Quantitation of the immunoelectron microscopical data was in excellent agreement with the biochemical results. After cholestyramine treatment there was an eightfold increase in the density of gold particles per peroxisome, and we estimate about a threefold increase in the labeling of the ER.

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