3-Hydroxy-3-methylglutaryl coenzyme A reductase: regulation of enzymatic activity by phosphorylation and dephosphorylation.

Regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase by reversible phosphorylation-dephosphorylation.

Evidence for phosphorylation/dephosphorylation of rat liver acyl-CoA:cholesterol acyltransferase.

Acyl-coenzyme A:cholesterol O-acyltransferase (ACATase; EC 2.3.1.26) is a membrane-bound microsomal enzyme that catalyzes the formation of long-chain fatty-acyl cholesterol esters in rat liver and other tissues. This enzyme is important in regulating the concentration of unesterified cholesterol in the cell. Having recently demonstrated that rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reduc...

Reversible inactivation-reactivation of 3-hydroxy-3-methylglutaryl coenzyme A reductase of rat intestine.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in the ileum of rats was inactivated by Mg2+-ATP and reversibly reactivated by cytoplasmic activator from the liver. The mevalonate kinase reaction was presumably not involved in this inactivation. Studies of nucleotide specificity for the inactivation revealed that ATP was most effective in the reaction among the nucleotides tested. In ...

In vivo modulation of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase, reductase kinase, and reductase kinase kinase by mevalonolactone.

It has been previously demonstrated that the enzymic activity of rat liver 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase; EC 1.1.1.34) is modulated in vitro and in vivo by a bicyclic cascade system involving reversible phosphorylation of HMG-CoA reductase and reductase kinase. In the present study, administration of mevalonolactone to rats caused a rapid inhibition of HMG-C...

3-Hydroxy-3-methylglutaryl coenzyme A reductase activity in the human gastrointestinal tract.

Activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34) was measured in intestinal mucosa of the human gastrointestinal tract. Activity was highest in gastric mucosa (18.2 pmol per mg per min) and there was a constant low level in the small bowel and colon (approximately 10 pmol per mg per min). Phosphorylation/dephosphorylation modulation of intestinal reductase activity was ...