Biosynthesis of presqualene pyrophosphate by liver microsomes.
نویسنده
چکیده
Microsomes from rat liver have been shown to synthesize a squalene precursor from farnesyl pyrophosphate. This intermediate is identical with presqualene pyrophosphate, a 30-carbon cyclopropane containing pyrophosphate ester that had previously been isolated from yeast. The squalene precursor was found to be tightly, but not covalently, bound to microsomes.
منابع مشابه
Liver Supernatant or Sterol Carrier Protein1 in the Enzymatic Conversion of Farnesyl Pyrophosphate to Squalene by Rat Liver Microsomes*
Earlier studies (Rilling, H. C. (1972) Biochem. Biophys. Res. Commun. 46, 470-475) suggested the possibility that a sterol carrier protein participated in the enzymatic conversion of farnesyl pyrophosphate to squalene by liver microsomal membranes. In the present article the possible requirement for soluble proteins in liver 105,000 x g supernatant (Slos) in the enzymatic conversion of farnesyl...
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Isolated peroxisomes were able to utilize [3H]isopentenyl diphosphate to synthesize farnesyl diphosphate, which then was utilized as substrate by both the peroxisomal squalene synthetase and cis-prenyltransferase. The specific activity of squalene synthetase in peroxisomes was as high as in microsomes, i.e. 160 pmol/mg of protein/min. If NADPH was omitted from the assay medium, presqualene diph...
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The intermediate, discovered by Rilling, between farnesyl pyrophosphate and squalene was synthesized in milligram quantities with yeast subcellular particles from farnesylJ4Cpyrophosphate and from farnesyl-l-3H&4C-pyrophosphate. The 3H : l4C ratio in the new squalene precursor was found to be identical with that in the farnesyl pyrophosphate, whereas the ratio in squalene was close to the expec...
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Recent studies on cholesterol biosynthesis have demonstrated that the biosynthesis of squalene from its immediate precursor, farnesyl pyrophosphate, is accompanied by the exchange of 1 hydrogen atom at C-l, in 1 of the 2 precursor molecules, for a hydride ion derived from reduced triphosphopyridine nucleotide (l-3). Thus, Popjak et al. obsrrved that the farnesol of farnesyl pyrophosphate biosyn...
متن کاملStudies on the Biosynthesis of Cholesterol
We have recently presented evidence indicating that during biosynthesis of squalene from farnesyl pyrophosphate by rat liver microsomes, 1 hydrogen atom attached to carbon 1 of 1 of the 2 precursor molecules condensing to squalene was exchanged for a hydride ion derived from reduced triphosphopyridine nucleotide (1). This conclusion was drawn from the observations, (a) that during synthesis of ...
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ورودعنوان ژورنال:
- Journal of lipid research
دوره 11 5 شماره
صفحات -
تاریخ انتشار 1970