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Bennati AM, Castelli M, Della Fazia MA, Beccari T, Caruso D, Servillo G, Roberti R. Sterol dependent regulation of human TM7SF2 gene expression: role of the encoded 3beta-hydroxysterol Delta14-reductase in human cholesterol biosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1761:677-85. [PMID: 16784888 DOI: 10.1016/j.bbalip.2006.05.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 05/04/2006] [Accepted: 05/04/2006] [Indexed: 11/26/2022]
Abstract
3Beta-hydroxysterol Delta(14)-reductase operates during the conversion of lanosterol to cholesterol in mammalian cells. Besides the endoplasmic reticulum 3beta-hydroxysterol Delta(14)-reductase (C14SR) encoded by TM7SF2 gene, the lamin B receptor (LBR) of the inner nuclear membrane possesses 3beta-hydroxysterol Delta(14)-reductase activity, based on its ability to complement C14SR-defective yeast strains. LBR was indicated as the primary 3beta-hydroxysterol Delta(14)-reductase in human cholesterol biosynthesis, since mutations in LBR gene were found in Greenberg skeletal dysplasia, characterized by accumulation of Delta(14)-unsaturated sterols. This study addresses the issue of C14SR and LBR role in cholesterol biosynthesis. Both human C14SR and LBR expressed in COS-1 cells exhibit 3beta-hydroxysterol Delta(14)-reductase activity in vitro. TM7SF2 mRNA and C14SR protein expression in HepG2 cells grown in delipidated serum (LPDS) plus lovastatin (sterol starvation) were 4- and 8-fold higher, respectively, than in LPDS plus 25-hydroxycholesterol (sterol feeding), resulting in 4-fold higher 3beta-hydroxysterol Delta(14)-reductase activity. No variations in LBR mRNA and protein levels were detected in the same conditions. The induction of TM7SF2 gene expression is turned-on by promoter activation in response to low cell sterol levels and is mediated by SREBP-2. The results suggest a primary role of C14SR in human cholesterol biosynthesis, whereas LBR role in the pathway remains unclear.
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Affiliation(s)
- Anna Maria Bennati
- Department of Internal Medicine, Laboratory of Biochemistry, University of Perugia, Via del Giochetto, 06122 Perugia, Italy
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Xiong Q, Ruan B, Whitby FG, Tuohy RP, Belanger TL, Kelley RI, Wilson WK, Schroepfer GJ. A colorimetric assay for 7-dehydrocholesterol with potential application to screening for Smith-Lemli-Opitz syndrome. Chem Phys Lipids 2002; 115:1-15. [PMID: 12047895 DOI: 10.1016/s0009-3084(01)00205-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Smith-Lemli-Opitz syndrome (SLOS; MIM 270400) is a genetic disorder characterized by hypocholesterolemia and elevated 7-dehydrocholesterol (7DHC) levels resulting from mutations affecting 7-dehydrocholesterol reductase. We describe a colorimetric assay for 7DHC with potential application to large-scale screening for SLOS. Reaction of 7DHC and its esters with the Liebermann-Burchard reagent resulted in a brief initial absorbance at 510 nm (pink color) followed by an absorbance at 620 nm (blue color) after 2 min, while cholesterol samples were essentially colorless. The assay could identify typical SLOS blood samples by their pink color and increased absorbance at 620 nm after 2 min. Colorimetric identification of mild SLOS cases requires monitoring of the transient absorbance at 510 nm, which must be detected immediately after rapid, consistent mixing of the reagents. The need for special mixing devices and rigorous validation precludes sporadic use of the assay for diagnosing suspected SLOS cases. We also studied the stability of 7DHC in dried SLOS blood spots on Guthrie cards, which are widely used for archiving neonatal blood. Decomposition of 7DHC was effectively retarded by storage at low temperature and by precoating of the cards with antioxidants. The combined results provide a foundation for development of a simple, automated test for SLOS screening.
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Affiliation(s)
- Quanbo Xiong
- Department of Biochemistry and Cell Biology, Rice University, MS140, 6100 Main Street, Houston, TX 77005-1892, USA
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Roberti R, Bennati AM, Galli G, Caruso D, Maras B, Aisa C, Beccari T, Della Fazia MA, Servillo G. Cloning and expression of sterol Delta 14-reductase from bovine liver. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:283-90. [PMID: 11784322 DOI: 10.1046/j.0014-2956.2001.02646.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Biosynthesis of cholesterol represents one of the fundamental cellular metabolic processes. Sterol Delta 14-reductase (Delta 14-SR) is a microsomal enzyme involved in the conversion of lanosterol to cholesterol in mammals. Amino-acid sequence analysis of a 38-kDa protein purified from bovine liver in our laboratory revealed > 90% similarity with a human sterol reductase, SR-1, encoded by the TM7SF2 gene, and with the C-terminal domain of human lamin B receptor. A cDNA encoding the 38-kDa protein, similar to human TM7SF2, was identified by analysis of a bovine expressed sequence tag (EST) database. The cDNA was synthesized by RT-PCR, cloned, and sequenced. The cDNA encodes a 418 amino-acid polypeptide with nine predicted transmembrane domains. The deduced amino-acid sequence exhibits high similarity with Delta 14-SR from yeasts, fungi, and plants (55-59%), suggesting that the bovine cDNA encodes Delta 14-SR. Northern blot analysis of bovine tissues showed high expression of mRNA in liver and brain. The polypeptide encoded by the cloned cDNA was expressed in COS-7 cells. Immunofluorescence analysis of transfected cells revealed a distribution of the protein throughout the ER. COS-7 cells expressing the protein exhibited Delta 14-SR activity about sevenfold higher than control cells. These results demonstrate that the cloned bovine cDNA encodes Delta 14-SR and provide evidence that the human TM7SF2 gene encodes Delta 14-SR.
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Affiliation(s)
- Rita Roberti
- Department of Internal Medicine, University of Perugia, Italy.
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5
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Aberrant pathways in the late stages of cholesterol biosynthesis in the rat: origin and metabolic fate of unsaturated sterols relevant to the Smith-Lemli-Opitz syndrome. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31970-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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6
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Izumi A, Pinkerton F, Nelson S, Pyrek J, Neill P, Smith JH, Schroepfer G. Inhibitors of sterol synthesis. Submicromolar 14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta, 15 alpha-diol causes a major modification of the sterol composition of CHO-K1 cells and a marked change in cell morphology. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)39968-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Kudo K, Emmons GT, Casserly EW, Via DP, Smith LC, St Pyrek J, Schroepfer GJ. Inhibitors of sterol synthesis. Chromatography of acetate derivatives of oxygenated sterols. J Lipid Res 1989. [DOI: 10.1016/s0022-2275(20)38296-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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8
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Pajewski TN, Brabson JS, Kisic A, Wang KS, Hylarides MD, Jackson EM, Schroepfer GJ. Inhibitors of sterol synthesis. Metabolism of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one after oral administration to a nonhuman primate. Chem Phys Lipids 1989; 49:243-63. [PMID: 2720860 DOI: 10.1016/0009-3084(89)90072-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
5 alpha-Cholest-8(14)-en-3 beta-ol-15-one is a potent inhibitor of cholesterol biosynthesis which has significant hypocholesterolemic activity upon oral administration to rodents and nonhuman primates. In the present study the metabolism of the 15-ketosterol has been investigated after the oral administration of a mixture of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one and [4-14C]cholesterol to 8 baboons. Blood samples were obtained at 4, 8, 12, 16, and 24 h after administration of the labeled sterols. Clear differences in the time courses of the levels of 3H and 14C in plasma were observed. 3H in plasma showed maximum values at 4 to 8 h, whereas maximum values for the levels of 14C were observed much later. 3H in plasma was shown to be primarily in the form of its metabolites, i.e. esters of the 15-ketosterol, cholesterol, and cholesteryl esters. The levels of the 15-ketosterol and of each of these metabolites showed different changes with time. The labeled cholesterol (and the cholesterol moiety of the cholesteryl esters), formed from the [2,4-3H]-15-ketosterol, was characterized by chromatography and by purification by way of its dibromide derivative. At 24 h after the administration of the labeled sterols, the distribution of 3H in plasma lipoprotein fractions paralleled that of 14C, with most of the 3H and 14C in high density lipoprotiens (HDL) and low density lipoproteins (LDL). Almost all of the 3H in HDL and in LDL was found as cholesterol, cholesteryl esters and esters of the 15-ketosterol. The distribution of 3H in HDL and in LDL of the free 15-ketosterol, esters of the 15-ketosterol, cholesterol, and cholesteryl esters was similar to that of plasma, thereby indicating no unusual concentration of any of the 3H labeled components in HDL or LDL.
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Affiliation(s)
- T N Pajewski
- Department of Biochemistry, Rice University, Houston, TX 77251
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Pajewski TN, Pinkerton FD, Miller LR, Schroepfer GJ. Inhibitors of sterol synthesis. Studies of the metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one in Chinese hamster ovary cells and its effects on activities of early enzymes in cholesterol biosynthesis. Chem Phys Lipids 1988; 48:153-68. [PMID: 2907421 DOI: 10.1016/0009-3084(88)90086-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The metabolism of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one (I) has been studied in Chinese hamster ovary (CHO-K1) cells which were maintained in a lipid-deficient medium. The incorporation of I into the cells was linear with respect to sterol concentration in the medium over the ranges of concentrations studied and was more than 3.5 times that of the uptake of cholesterol. The results of detailed chromatographic analyses of the lipids recovered from the cells after 6 h of incubation with [2,4-3H]I (0.5 microM or 6.0 microM) indicated that most of the 3H was associated with free I. Considerably lesser amounts of the 3H was associated with esters of I. No formation of [3H]cholesterol or [3H]cholesteryl esters (or other C27 monohydroxysterols) from labeled I was observed. The labeled material with the chromatographic behavior of the esters of I gave, after mild alkaline hydrolysis, the free 15-ketosterol which was characterized by the results of chromatographic and cocrystallization studies. Upon transfer of the CHO-K1 cells from a culture medium containing 8% newborn calf serum to the same medium containing 8% lipid-deficient newborn calf serum, increases in the levels of activity of cytosolic acetoacetyl-CoA thiolase and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase and of HMG-CoA reductase were observed. These increases were blocked by the addition of I at a concentration of 1.0 microM. I (1.0 microM) also caused a decrease in the levels of activity of the three enzymes in cells previously grown in medium containing lipid-deficient serum. These results demonstrate that I not only affects the enzymatic reduction of HMG-CoA but also the enzymatic formation of this key intermediate in cholesterol biosynthesis.
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Affiliation(s)
- T N Pajewski
- Department of Biochemistry and Chemistry, Rice University, Houston, TX 77251
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Brabson JS, Schroepfer GJ. Inhibitors of sterol synthesis. Studies of the distribution and metabolism of 5 alpha-[2,4-3H]cholest-8(14)-en-3 beta-ol-15-one after intragastric administration to rats. Steroids 1988; 52:51-68. [PMID: 3247671 DOI: 10.1016/0039-128x(88)90217-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
5 alpha-[2,4-3H]Cholest-8(14)-en-3 beta-ol-15-one was administered to a series of male Sprague-Dawley rats by intragastric intubation in the form of an emulsion in a mixture of triolein, sodium taurocholate, bovine serum albumin, and glucose. [4-14C]Cholesterol was similarly administered to a second series of rats. The distribution of 3H and 14C was studied at 12 and 48 h after the administration of the sterols. The results demonstrated that the 15-ketosterol is absorbed and metabolized to material with the chromatographic properties of fatty acid esters of the 15-ketosterol, to cholesterol, and to fatty acid esters of cholesterol. The [3H]cholesterol formed from the 15-ketosterol was characterized by its behavior on silicic acid-Super Cel column chromatography, by the chromatographic behavior of its acetate derivative on alumina-AgNO3 column chromatography, and by purification by way of its dibromide derivative without significant change in specific activity. The general distribution of 3H was similar to that of 14C. No unusual concentration of 3H in any of the organs studied was observed.
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Affiliation(s)
- J S Brabson
- Department of Biochemistry, Rice University, Houston, TX 77251
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11
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Monger DJ, Schroepfer GJ. Inhibitors of cholesterol biosynthesis. Further studies of the metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one in rat liver preparations. Chem Phys Lipids 1988; 47:21-46. [PMID: 3396133 DOI: 10.1016/0009-3084(88)90030-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
5 alpha-Cholest-8(14)-en-3 beta-ol-15-one is a potent inhibitor of sterol biosynthesis in mammalian cells in culture and has significant hypocholesterolemic activity upon oral administration to rodents and non-human primates. The conversion of the 15-ketosterol to cholesterol upon incubation with the 10,000 x g supernatant fraction of rat liver homogenate preparations under aerobic conditions has been reported (D.J. Monger, E.J. Parish and G.J. Schroepfer, Jr. (1980) J. Biol. Chem. 255, 11122-11129). Presented herein are results of studies of the metabolism of [2,4-3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one obtained upon incubation with the microsomal, cytosolic and the 10,000 x g supernatant fractions of liver homogenates of female rats under a variety of conditions. The results of these studies indicated metabolism of the 15-ketosterol to materials with the chromatographic properties of fatty acid esters of the 15-ketosterol, fatty acid esters of C27-monohydroxysterols, a component similar to the 15-ketosterol (possibly an isomer of the delta 8(14)-15-ketosterol), and a polar component. Detailed studies of the C27-monohydroxysterols obtained from incubation of the 15-ketosterol under anaerobic conditions indicated the formation of labeled 5 alpha-cholesta-8,14-dien-3 beta-ol and 5 alpha-cholest-7-en-3 beta-ol which were characterized by their behavior on silicic acid column chromatography, by the behavior of their acetate derivatives on medium pressure liquid chromatography on alumina-AgNO3 columns, and by co-crystallization of the labeled sterols with authentic unlabeled standards. The identification of 5 alpha-cholesta-8,14-dien-3 beta-ol and 5 alpha-cholest-7-en-3 beta-ol as metabolites of the 15-ketesterol, coupled with previous studies of the metabolism of 5 alpha-cholesta-8,14-dien-3 beta-ol and of 5 alpha-cholest-8(14)-ene-3 beta, 15 alpha-diol and 5 alpha-cholest-8(14)-ene-3 beta, 15 beta-diol has permitted the formulation of a scheme for the overall metabolism of the 15-ketosterol to cholesterol.
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Affiliation(s)
- D J Monger
- Department of Biochemistry, Rice University, Houston, TX 77251
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Schroepfer GJ, Kisic A, Izumi A, Wang KS, Carey KD, Chu AJ. Inhibitors of sterol synthesis. Metabolism of [2,4-3H]5 alpha-cholest-8(14-)-en-3 beta-ol-15-one after intravenous administration to a nonhuman primate. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68896-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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13
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Inhibitors of sterol synthesis. Metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one after intravenous administration to bile duct-cannulated rats. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68897-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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14
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Schroepfer GJ, Pajewski TN, Hylarides M, Kisic A. 5 alpha-Cholest-8(14)-en-3 beta-ol-15-one. In vivo conversion to cholesterol upon oral administration to a nonhuman primate. Biochem Biophys Res Commun 1987; 146:1027-32. [PMID: 3619912 DOI: 10.1016/0006-291x(87)90750-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The metabolism of 5 alpha-cholest-8(14)-en-3 beta-ol-15-one (I), a potent inhibitor of cholesterol synthesis with marked hypocholesteremic activity, has been studied in a nonhuman primate. A mixture of [2,4-3H]-I and [4-14C]-cholesterol was administered to a male baboon in the form of a feedball. Blood was samples at 4, 8, 12, 16, and 24 hr. Detailed analyses of the plasma lipids indicated very rapid absorption of I (relative to cholesterol) and metabolism to cholesterol, cholesteryl esters, and esters of I. The labeled cholesterol was characterized by chromatographic techniques and by purification by way of its dibromide derivative. The levels of 3H in plasma associated with I, esters of I, cholesterol, and cholesteryl esters each showed a different time course. By 24 hr after the administration of [2,4-3H]-I, most of the 3H in plasma was associated with cholesterol and cholesteryl esters. The levels of total 3H and 14C in plasma at various times after the administration of the mixture of [2,4-3H]-I and [4-14C]-cholesterol differed markedly with 3H showing a maximum value at 4 hr and 14C showing a maximum value at 24 hr.
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Abstract
Bovine retinas were incubated with 3RS-[5-3H]-mevalonic acid under conditions similar to those previously shown to support opsin biosynthesis in vitro. TLC of the total lipids indicated the formation of numerous radiolabeled components, including sterols, hydrocarbons, and "fatty acid-like material." The nonsaponifiable lipids were analyzed by TLC, GLC, and chromatography on columns of silicic acid-Super Cel, silica gel G-Super Cel-silver nitrate, and alumina-Super Cel-silver nitrate. The major nonsaponifiable components had the chromatographic properties of squalene and "methylated sterols" (i.e., C30, C29, and C28 monohydroxy sterols). Cholesterol represented no more than 1% of the total radioactivity in the nonsaponifiable lipid fraction. The "fatty acid-like material" was derivatized with diazomethane, and the resulting methyl esters were analyzed by GLC before and after catalytic hydrogenation. The radioactivity did not correspond to the normal fatty acids endogenous to the retina, but rather had the chromatographic properties of C15 and C20 isoprenoid acids. These results obtained with intact retinas are consistent with our previous observations concerning mevalonic acid metabolism in cell-free homogenates of bovine retinas.
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Paik YK, Trzaskos JM, Shafiee A, Gaylor JL. Microsomal enzymes of cholesterol biosynthesis from lanosterol. Characterization, solubilization, and partial purification of NADPH-dependent delta 8,14-steroid 14-reductase. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)90710-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Metabolism of mevalonic acid in cell-free homogenates of bovine retinas. Formation of novel isoprenoid acids. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43771-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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18
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Fliesler SJ, Schroepfer GJ. Sterol composition of bovine retinal rod outer segment membranes and whole retinas. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 711:138-48. [PMID: 7066367 DOI: 10.1016/0005-2760(82)90020-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The sterol composition of bovine retinal rod outer segment membranes and whole retinas was studied by detailed chromatographic analyses. Cholesterol represented at least 98% of the total 3 beta-monohydroxy sterols of rod outer segment membranes, accounting for 1.68 +/- 0.15% of the dry weight. Whole retinas contained 1.76 +/- 0.29% cholesterol by dry weight, representing at least 99% of the total 3 beta-monohydroxy sterols. Trace amounts of a component having the chromatographic properties of 5 alpha-cholestan-3 beta-ol were found in rod outer segment membranes and whole retinas. Very small amounts of a component having the chromatographic properties of 5 alpha-cholest-7-en-3 beta-ol were found in whole retinas, but not in rod outer segment membranes. The molar ratio of cholesterol to rhodopsin in bovine rod outer segment membranes was approximately 4.7. Cholesterol accounted for only 5-7 mol% of total rod outer segment membrane lipids.
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Miller LR, Pajewski TN, Schroepfer GJ. Inhibitors of sterol synthesis. Studies of in vitro effects of C27 15-oxygenated sterols on sterol synthesis in cell free homogenates of rat liver. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34939-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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20
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14 alpha-Ethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol, a potent inhibitor of sterol biosynthesis, has two sites of action in cultured mammalian cells. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)68128-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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21
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Miller L, Pascal R, Schroepfer G. Inhibitors of sterol synthesis. Differential effects of 14 alpha-hydroxymethyl-5 alpha-cholest-7-ene-3 beta, 15 alpha-diol and 14 alpha-hydroxymethyl-5 alpha-cholest-6-ene-3 beta, 15 alpha-diol on sterol synthesis in cell-free homogenates of rat liver. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)43392-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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22
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Rip J, Rupar C, Chaudhary N, Carroll K. Localization of a dolichyl phosphate phosphatase in plasma membranes of rat liver. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69896-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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23
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Monger D, Parish E, Schroepfer G. 15-Oxygenated sterols. Enzymatic conversion of [2,4]3H]5 alpha-cholest-8(14)-en-3 beta-ol-15-one to cholesterol in rat liver homogenate preparations. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70264-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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24
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Schroepfer GJ, Parish EJ, Pascal RA, Kandutsch AA. Inhibition of sterol biosynthesis in animal cells by 14 alpha-hydroxymethyl sterols. J Lipid Res 1980. [DOI: 10.1016/s0022-2275(20)42227-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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25
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Pascal R, Schroepfer G. 15-Oxygenated sterols with the unnatural cis-C-D ring junction. Studies of the metabolism of 5 alpha,14 beta-cholest-7-ene-3 beta,15 alpha-diol and 5 alpha,14 beta-cholest-7-ene-3 beta,15 beta-diol. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85738-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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Pascal RA, Farris CL, Schroepfer GJ. Sterol synthesis: medium-pressure chromatography of C27 sterol precursors of cholesterol on alumina-silver nitrate columns. Anal Biochem 1980; 101:15-22. [PMID: 7356123 DOI: 10.1016/0003-2697(80)90033-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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27
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Parish EJ, Schroepfer GJ. Chemical syntheses of 5α-cholesta-6,8(14)-dien-3β-ol-15-one and related 15-oxygenated sterols. Chem Phys Lipids 1979. [DOI: 10.1016/0009-3084(79)90076-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Chan JT, Spike TE, Trowbridge ST, Schroepfer GJ. Sterol synthesis: studies of the metabolism of 14 alpha-methyl-5 alpha-cholest-7-en-3 beta-ol. J Lipid Res 1979. [DOI: 10.1016/s0022-2275(20)40003-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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29
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30
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Thowsen JR, Schroepfer GJ. Sterol synthesis. High-pressure liquid chromatography of C27 sterol precursors of cholesterol. J Lipid Res 1979. [DOI: 10.1016/s0022-2275(20)40594-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Huntoon S, Fourcans B, Lutsky B, Parish E, Emery H, Knapp F, Schroepfer G. Sterol Synthesis. Chemical syntheses, spectral properties, and metabolism of 5alpha-cholest-8(14)-en-3beta,15beta-diol and 5alpha-cholest-8(14)-en-3beta,15alpha-diol. J Biol Chem 1978. [DOI: 10.1016/s0021-9258(17)38170-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Parish EJ, Schroepfer GJ. Sterol synthesis. Syntheses of 15-oxygenated 5alpha, 14beta-cholest-7-en-3beta-ol derivatives. Chem Phys Lipids 1977; 19:107-13. [PMID: 880727 DOI: 10.1016/0009-3084(77)90091-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Treatment of 3beta-benzoyloxy-14alpha, 15alpha-epoxy-5alpha-cholest-7-ene with boron trifluoride-etherate gave, in 43% yield, 3alpha-benzoyloxy-5alpha, 14beta-cholest-7-en-15-one with the unnatural C-D ring juncture. Reduction of the latter compound with lithium aluminum hydride gave 15alpha, 14beta-cholest-7-en-3beta, 15alpha-diol and 5alpha, 14beta-cholest-7-en-3beta, 15beta-diol in 9% and 81% yields, respectively.
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Adler JH, Patterson GW. Metabolism of 2,4-3H-14alpha-methyl-5alpha-ergost-8-enol and 2,4-3H-5alpha-ergosta-8,14-dienol in Ochromonas malhamensis. Lipids 1976; 11:634-6. [PMID: 987520 DOI: 10.1007/bf02532878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Tritium-labeled 14alpha-methyl-5alpha-ergost-8-enol and 5alpha-ergosta-8,14-dienol were converted to brassicasterol and poriferasterol in Ochromonas malhamensis. This indicates that the organism can rearrange these sterol structures so that they contain the naturally occurring 5(6) double bond, and suggests that O. malhamensis is able to introduce a 24(28) double bond into a nine-carbon saturated side chain which is alkylated to produce a C-29 sterol.
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Hsiung HM, Spike TE, Schroepfer GJ. Enzymatic conversion of 5alpha-cholesta-7, 14-dien-3beta-ol to 5alpha-cholesta-8, 14-dien-3beta-ol. Lipids 1975; 10:623-6. [PMID: 1186448 DOI: 10.1007/bf02532727] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
5alpha-Cholesta-7, 14-dien-3beta-ol, previously shown to be efficiently converted to cholesterol upon incubation with rat liver homogenate preparations under aerobic conditions, has been studied as to its possible conversion to 5alpha-cholesta-8, 14-dien-3beta-ol. Efficient conversion was observed upon incubation in the presence of washed mictosomes of rat liver under anaerobic conditions. This observation is of importance in consideration of possible metabolic pathways in the biosythesis of cholesterol.
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Lutsky BN, Hsiung HM, Schroepfer GJ. Inhibition of enzymatic reduction of delta 14-double bond of 5 alpha-cholesta-8,14-dien-3 beta-ol and 5 alpha-cholesta-7,14-dien-3 beta-ol by AY-9944. Lipids 1975; 10:9-11. [PMID: 1123977 DOI: 10.1007/bf02532186] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AY-994 (trans-1,4-bis-(2-chlorobenzyl-aminomethyl) cyclohexane dihydrochloride), a potent inhibitor of the enzymatic reduction of the delta 7-double bond of delta 5,7-sterols, has been shown to inhibit, at higher concentrations (10-4 M), the enzymatic reduction of the delta 14-double bond of cholesta-8,14-dien-3 beta-ol and cholesta-7,14-dien-3 beta-ol.
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Tsai LB, Patterson GW, Cohen CF. Metabolism of 2,4 -3H - 14alpha-methyl -5alpha-ergost - 8-enol and 2,4- 3H- 5 alpha- ergosta-8, 14-dienol in chlorella ellipsoidea. Lipids 1974; 9:1014-7. [PMID: 4444422 DOI: 10.1007/bf02533828] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Lutsky BN, Schroepfer GJ. Enzymatic conversion of 5alpha-cholest-8(14)-en-3beta-o1 to 5alpha-cholesta-8,14-dien-3beta-o1. Lipids 1971; 6:957-9. [PMID: 5163761 DOI: 10.1007/bf02531180] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Lutsky BN, Martin J, Schroepfer G. Studies of the Metabolism of 5α-Cholesta-8,14-dien-3β-ol and 5α-Cholesta-7,14-dien-3β-ol in Rat Liver Homogenate Preparations. J Biol Chem 1971. [DOI: 10.1016/s0021-9258(19)45907-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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