Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
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Drug
Enzyme
Compound
Query: EC:6.2.1.13 (
acetyl-CoA synthetase
)
451
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Phenylmethylsulfonyl fluoride (PMSF), a reagent commonly employed for the inhibition of serine proteases, has been found to cause significant inhibition of the incorporation of labeled acetate, but not mevalonate, into nonsaponifiable lipid and digitonin-precipitable sterols in the 10,000 X g supernatant fraction of rat liver homogenate preparations. In two experiments, the extent of inhibition of the synthesis of digitonin-precipitable sterols from acetate by PMSF at 1 mM was 81 and 65%. PMSF inhibited the synthesis of nonsaponifiable lipid from acetate at concentrations as low as 0.1 microM. Preincubation of the 10,000 X g supernatant fraction of rat liver homogenates with PMSF (1 mM) resulted in a significant reduction of the activities of
acetate thiokinase
and 3-hydroxy-3-methylglutaric acid (HMG)-CoA synthase, but did not affect the activities of acetoacetyl-CoA thiolase. Preincubation of rat liver microsomes with PMSF (1 mM) caused a 50% reduction in the level of
HMG-CoA reductase
activity. The combined results indicate that major sites of action of PMSF in the inhibition of sterol biosynthesis from labeled acetate appear to be on the activities of
acetate thiokinase
, HMG-CoA synthase, and
HMG-CoA reductase
. Another reagent used to inhibit serine proteases, diisopropylfluorophosphate, had (at a concentration of 1 mM) no effect on the activities of cytosolic acetoacetyl-CoA thiolase, HMG-CoA synthase, and
HMG-CoA reductase
.
...
PMID:Effect of phenylmethylsulfonyl fluoride on sterol biosynthesis in 10,000 x g supernatant fraction of rat liver homogenates. 611 96
Cycloheximide, frequently used as an inhibitor of protein synthesis in vivo and in vitro, has been found to cause a significant reduction of the synthesis of digitonin-precipitable sterols from acetate, but not from mevalonate, at a concentration of 1 mM in the 10,000 x g supernatant fraction of rat liver homogenate preparations. The results of studies of the metabolism of labeled leucine under the same conditions indicated that the effect of cycloheximide on sterol synthesis from acetate was not related to an effect of cycloheximide on protein synthesis. Preincubation of the 10,000 x g supernatant fraction of rat liver homogenates with cycloheximide (1 mM) caused a significant reduction in the levels of
acetate thiokinase
and hydroxymethylglutaryl-CoA synthase activities but not of acetoacetyl-CoA thiolase activity. Preincubation of the 100,000 x g supernatant fraction of rat liver homogenates with cycloheximide (1 mM or 0.3 mM) also caused a significant reduction of the levels of hydroxymethylglutaryl-CoA synthase activity. When cycloheximide (1 mM) was preincubated with the 100,000 x g supernatant fraction, a reduction in the level of
acetate thiokinase
activity was observed. Preincubation of rat liver microsomes with cycloheximide (1 mM and 3 mM) had no effect on the level of
hydroxymethylglutaryl-CoA reductase
activity. These results suggest that biological effects observed upon exposure of cells or tissues to high concentrations of cycloheximide may not be exclusively due to effects of the cycloheximide on the synthesis of protein.
...
PMID:Cycloheximide inhibits sterol biosynthesis in cell-free preparations of rat liver. 737 3
