Studies on the biosynthesis of cholesterol. III. Purification of C14-cholesterol from perfusions of livers and other organs

Schwenk, Erwin; Werthessen, Nicholas T.

doi:10.1016/0003-9861(52)90119-7

Cited by 197 publications

(39 citation statements)

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“…Cholesterol was obtained from Sigma Co., St. Louis, Mo., and further purified through bromination according to the method of Schwenk and Werthessen (14). L-a-Dipalmitoyl PC was purchased from Calbiochem, La Jolla, Calif.…”

Section: Experimental Materials and Proceduresmentioning

confidence: 99%

Differential Interaction of Cholesterol with Phosphatidylcholine on the Inner and Outer Surfaces of Lipid Bilayer Vesicles

Huang

Sipe

Chow

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

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The Proton nuclear magnetic resonance (PMR) spectroscopy has been applied extensively in recent years to elucidate the structural or conformational properties of phospholipids and biomembranes (1). Most of these studies, however, are concerned primarily with the mobility of fatty acyl chains of the bilayer (2, 3). As reported several times (4-6), paramagnetic ions such as europium (Eug+) added to the exterior of lipid vesicles shift the field position of the -N+(CHI3)3protons of phosphatidylcholine (PC) molecules that reside on the outer surface of lipid vesicles, which are closed shelllike spheres of about 250 X in diameter, each comprised of a single, continuous, lipid-bilayer membrane enclosing a volume of aqueous solution (7). Using these paramagnetic ions as shift markers, the head groups in the two halves of vesicle bilayers can be spectrally identified. Consequently, the application of PMR technique has now been extended to investigate the structural properties of the outer and (or) inner polar head regions of the bilayer. The interaction of phospholipid with cholesterol in the bilayer structure has been studied recently by a variety of physical techniques (8-10). On the basis of these studies, it has been proposed that the effect of cholesterol on phospholipids in the bilayer structure is to restrict differentially the number of steric conformations accessible to the segments of the fatty acyl chains (11). However, more recent studies have shown that the 3,8-OH group of cholesterol is also of crucial importance for phospholipid-sterol interaction (12, 13), and, as a consequence, interactions in the polar head regions of the bilayer should be examined further.In this preliminary communication, we report the effects of cholesterol content on the -N+(CH3)3 proton resonance signal of the vesicle bilayer in the presence of a paramagnetic lanthanide ion, praseodymium ion (Pr'+). We chose Pr'+ rather than Eu8+ as a shift marker to study differentially the two polar head regions of the vesicle bilayer because, at a lower concentration, the Pr'+ ions produced at greater spectral splitting of the -N+(CH3)3 resonance signal upon coordination with the polar head groups of the bilayer. EXPERIMENTAL MATERIALS AND PROCEDURESCholesterol was obtained from Sigma Co., St. Louis, Mo., and further purified through bromination according to the method of Schwenk and Werthessen (14). L-a-Dipalmitoyl PC was purchased from Calbiochem, La Jolla, Calif. Egg PC was isolated and purified as described previously (7)

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Section: Experimental Materials and Proceduresmentioning

confidence: 99%

Differential Interaction of Cholesterol with Phosphatidylcholine on the Inner and Outer Surfaces of Lipid Bilayer Vesicles

Huang

Sipe

Chow

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

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“…the cholesterol in aliquots of the acetone-alcohol extracts of serum, liver, kidney, spleen, and muscle were purified by the bromination method of Schwenk and Werthessen (6), and the cholesterol specific activity of the purified material was determined as previously described.…”

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confidence: 99%

Body Cholesterol Metabolism in Man. I. The Equilibration of Serum and Tissue Cholesterol*†

Chobanian¹,

Hollander²

1962

J. Clin. Invest.

184

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“…Presumptive evidence for a precursor even closer to cholesterol was found by Schwenk & Werth essen (149) in experiments on isolated organs perfused with blood containing C14-acetate. The digitonide obtained from the blood contained a highly radioactive substance, from which cholesterol could be separated only by conversion to the dibromoderivative.…”

Section: Synthesismentioning

confidence: 88%

Lipid Metabolism

Artom¹

1953

Annu. Rev. Biochem.

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In view of recommendation by the Editors that a critical evaluation should be attempted rather than a complete synopsis of this year's work, only a few aspects of lipid metabolism have been covered, and even here, selection has been necessary. The following subjects were abstracted but later omitted: nutritional value of fat, essential fatty acids, synthesis and metabolism of choline, choline oxidase, lipoproteins in human disease, aceto acetate formation and ketosis, obesity, lipid composition in tissue, cholesterol esterification, analytical procedures, and, to a large extent, also action of hormones and vitamins. DIGESTION AND ABSORPTION OF LIPIDSThis topic has been given specific attention in Volume 21 of this series [Frazer (1)] and elsewhere [Desnuelle (2); Favarger (3)]. Frazer's views have been presented again (4) and applied to the interpretation of the absorption defect in sprue and other steatorrhoeas (5, 6) . .The original observations by Artom & Reale that mono-and diglycerides are formed in both the digestion (7) and the synthesis (8) of fats by pancrea tic lipase have been amply confirmed. A preferential splitting of the 1,3 ester linkages with formation of 2�monoglycerides occurs in the pancreatic digestion of triglycerides of higher fatty acids (9), in that of the triglycerides of lower fatty acids 2,3-diglycerides are chiefly formed [Sch¢nheyder & Volqvartz (10)]. After fatty meals, the lipids in the intestinal lumen con tained 37 per cent to 50 per cent of monoglycerides [humans: Kuhrt et al. (lOa)]. or 16 per cent of mono-and 36 per cent of diglycerides [rats: Mattson et al. (lOb)]. However, both in vitro and in vivo, the relative proportion of the various products formed in the digestion of triglycerides is mark edly affected by the presence of Ca++ and bile salts [Desnuelle & Constantin (l1)J. Experiments with C14-palmitate indicate that, simultaneously with the hydrolysis, a resynthesis of the free fatty acid with the mono-and di glycerides occurs [Borgstrom (12»).From the analysis of the chyle of rats receiving triglycerides doubly labeled in the glycerol and fatty acid moieties, Reiser et al. (13) calculated that half or more of the fatty acids were absorbed as monoglycerides. A large portion of the labeled glycerol was metabolized, indicating that complete hydrolysis of the triglycerides also took place. Both free fatty acids and 1 The main period covered by this review is December 1951 to November 1952. 2 The following abbreviations are used: ADP for adenosine diphosphate; ATP for adenosinetriphosphate; eoA for coenzyme A; DME for dimethylethanolamine; DPN for diphosphopyridine nucleotide. 211 Annu. Rev. Biochem. 1953.22:211-232. Downloaded from www.annualreviews.org Access provided by McMaster University on 02/05/15. For personal use only. Quick links to online content Further ANNUAL REVIEWS

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Studies on the biosynthesis of cholesterol. III. Purification of C14-cholesterol from perfusions of livers and other organs

Cited by 197 publications

References 10 publications

Differential Interaction of Cholesterol with Phosphatidylcholine on the Inner and Outer Surfaces of Lipid Bilayer Vesicles

Differential Interaction of Cholesterol with Phosphatidylcholine on the Inner and Outer Surfaces of Lipid Bilayer Vesicles

Body Cholesterol Metabolism in Man. I. The Equilibration of Serum and Tissue Cholesterol*†

Lipid Metabolism

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