Inactivation of 3-hydroxy-3-methylglutaryl coenzyme A reductase in vitro. An adenine nucleotide-dependent reaction catalyzed by a factor in human fibroblasts.
نویسندگان
چکیده
Microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase prepared from either rat liver or human fibroblasts was shown to be inactivated in vitro by a factor in extracts of cultured human fibroblasts in a reaction requiring ATP or ADP and Mg2+ or Mn2+. The inactivation factor was found in the soluble fraction of fibroblasts extracts and was shown to be heat-labile, nondialyzable, and precipitable with ammonium sulfate. The inactivation reaction was prevented by the addition of either an ATP-regenerating system or an ADP-regenerating system, suggesting that the presence of both adenine nucleotides may be required. A series of kinetic experiments suggested that the fibroblast inactivation factor catalyzes the conversion of the microsomal enzyme from an active to an inactive form. The finding that solubilized preparations of 3-hydroxy-3-methylglutaryl coenzyme A reductase from both rat liver and human fibroblasts were resistant to inactivation raises the possibility that some unidentified microsomal component also may participate in the inactivation reaction.
منابع مشابه
Reversible inactivation-reactivation of 3-hydroxy-3-methylglutaryl coenzyme A reductase of rat intestine.
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In hepatomas, the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-controlling enzyme in cholesterol biosynthesis, is not normally suppressed by cholesterol. To examine the biochemical mechanism of this loss of feedback control of cholesterol synthesis, a comparison was made of the properties of 3-hydroxy-3-methylglutaryl coenzyme A reductase after solubilization and partia...
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 250 7 شماره
صفحات -
تاریخ انتشار 1975