Abstract：
:The activity of rat liver microsomal squalene epoxidase is inhibited effectively by digitonin. Concentrations of 0.8 to 1.2 mg/ml of digitonin cause total inhibition of microsomal (0.75 mg protein/ml) squalene epoxidase either in microsomes that were pretreated with digitonin and subsequently washed and subjected to epoxidase assay or when digitonin was added directly to the assay. The inhibition of squalene epoxidase by digitonin is concentration-dependent and takes place rapidly within 5 min of exposure of the microsomes to digitonin. Octylglucoside, dimethylsulfoxide, CHAPS, as well as cholesterol or total microsomal lipid extract were ineffective in restoring the digitonin-inhibited squalene epoxidase activity. Epoxidase activity in digitonin-treated microsomes was fully restored by Triton X-100. The reactivation by Triton X-100 displays a concentration optimum with maximal reactivation of the epoxidase (0.7 mg protein/ml) occurring at 0.2% Triton X-100. Microsomal 2,3-oxidosqualene-lanosterol cyclase is also inhibited by digitonin. Higher concentrations of digitonin are required to obtain full inhibition of the cyclase activity and only 40% inhibition of cyclase activity is observed at 1 mg/ml of digitonin. Solubilized (subunit size 55 to 66 kDa) and microsomal (subunit size 97 kDa) 3-hydroxy-3-methylglutaryl CoA reductase are totally unaffected by the same concentration of digitonin. Squalene synthetase, another microsomal enzyme in the biosynthetic pathway of cholesterol, is activated by digitonin. A 2.2-fold activation of squalene synthetase is observed at 0.8 mg/ml of digitonin. The results agree with a model in which squalene, and to a lesser degree 2,3-oxidosqualene, are segregated by digitonin into separate intramembranal pools.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
J Lipid Resjournal_title
Journal of lipid researchauthors
Eilenberg H,Klinger E,Przedecki F,Shechter Isubject
Has Abstractpub_date
1989-08-01 00:00:00pages
1127-35issue
8eissn
0022-2275issn
1539-7262journal_volume
30pub_type
杂志文章abstract：:Lipids are used as cellular building blocks and condensed energy stores and also act as signaling molecules. The glycerolipid/ fatty acid cycle, encompassing lipolysis and lipogenesis, generates many lipid signals. Reliable procedures are not available for measuring activities of several lipolytic enzymes for the purp...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D058438
更新日期：2016-01-01 00:00:00
abstract：:Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) has been applied primarily to the analysis of glycosphingolipids separated from other complex mixtures by TLC, but it is difficult to obtain quantitative profiling of each glycosphingolipid among the different spots on TLC by MALDI-MS. Thus, the ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D800038-JLR200
更新日期：2008-12-01 00:00:00
abstract：:Selectivity of CDP-choline:diacylglycerol choline phosphotransferase and CDP-ethanolamine:diacylglycerol ethanolamine phosphotransferase for molecular species of diglyceride has been studied in rat brain microsomes in vitro. Diglyceride-labeled microsomes were prepared by incubation with labeled sn-glycerol-3-phosphat...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1980-05-01 00:00:00
abstract：:Guinea pig gallbladder bile contains chenodeoxycholic acid (62 +/- 5%), ursodeoxycholic acid (8 +/- 5%), and 7-ketolithocholic acid (30 +/- 5%). All three bile acids became labeled to the same specific activity within 30 min after [3H]cholesterol was injected into bile fistula guinea pigs. When a mixture of [3H]ursode...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1990-07-01 00:00:00
abstract：:We have shown that expression of apolipoprotein (apo) C-III promotes VLDL secretion from transfected McA-RH7777 cells under lipid-rich conditions. To determine structural elements within apoC-III that confer to this function, we contrasted wild-type apoC-III with a mutant Ala23Thr originally identified in hypotriglyce...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M005108
更新日期：2010-06-01 00:00:00
abstract：:Serine palmitoyltransferase [EC 2.3.1.50] initiates the biosynthesis of sphingolipids by catalyzing the condensation of a fatty acyl-CoA with serine to yield the committed intermediate 3-ketosphinganine or one of its homologues. The presence of serine palmitoyltransferase in aorta was established under optimal assay c...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1986-07-01 00:00:00
abstract：:Subcellular localization of nonesterified cholesterol has been determined in normal human fibroblasts from cultures incubated with human low density lipoprotein (LDL). Nonesterified and esterified cholesterol content of fibroblasts, grown initially in the absence of cholesterol, increased significantly after a 1-hour ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1982-11-01 00:00:00
abstract：:Choline kinase catalyzes the phosphorylation of choline, the first step of phospholipid synthesis. Increased phosphorylation of choline is a hallmark characteristic of the malignant phenotype in a variety of neoplasms. However, in hypoxic cancer cells, choline phosphorylation is decreased. To understand the mechanism ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M021030
更新日期：2012-01-01 00:00:00
abstract：:Phospholipids serve as central structural components in cellular membranes and as potent mediators in numerous signaling pathways. There are six main classes of naturally occurring phospholipids distinguished by their distinct polar head groups that contain many unique molecular species with distinct fatty acid compos...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.D051581
更新日期：2014-11-01 00:00:00
abstract：:Monolayers of Caco-2 cells, a human enterocyte cell line, were incubated with [1-14C]15-hydroxyeicosatetraenoic acid (15-HETE), a lipid mediator of inflammation, and [1-14C]arachidonic acid. Both fatty acids were taken up readily and metabolized by Caco-2 cells. [1-14C]Arachidonic acid was directly esterified in cellu...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1990-05-01 00:00:00
abstract：:An in vitro assay to study lipolysis of very low density lipoproteins (VLDL) by heparan sulfate proteoglycan (HSPG-bound lipoprotein lipase (LPL) was developed. Optimal conditions for VLDL lipolysis by HSPG-bound LPL were obtained by incubating plastic wells with 0.5 microg HSPG and 1.5 microg LPL, subsequently. Contr...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1997-12-01 00:00:00
abstract：:HMG-CoA reductase inhibitors (statins) are effective lipid-altering drugs for the treatment of dyslipidemia in patients with type 2 diabetes mellitus. We conducted a randomized, double-blind, placebo-controlled, crossover design trial to determine the effects of simvastatin, 80 mg/day, on plasma lipid and lipoprotein ...
journal_title：Journal of lipid research
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1194/jlr.M500335-JLR200
更新日期：2005-12-01 00:00:00
abstract：:The effects of intravenous injection of lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNF) were investigated in cynomolgus monkeys (Macaca fascicularis). Injection of 20 micrograms/kg of LPS from E. coli (serotype 055:B5) into cynomolgus monkeys fed a monkey chow diet caused a twofold increase in plasma tr...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1990-06-01 00:00:00
abstract：:The lipin protein family, consisting of three members, was first identified early this century. In the last few years, the lipin proteins have been shown to have important roles in glycerolipid biosynthesis and gene regulation, and mutations in the corresponding genes cause lipodystrophy, myoglobinuria, and inflammato...
journal_title：Journal of lipid research
pub_type： 杂志文章,评审
doi：10.1194/jlr.R800052-JLR200
更新日期：2009-04-01 00:00:00
abstract：:The infrared (IR) and nuclear magnetic resonance (NMR) spectra of eight Delta(24)-steroids and nine C-24 saturated steroids were examined. NMR spectra allow unambiguous assignment of the biologically important Delta(24)-bond; introduction of a Delta(24)-bond causes the appearance of peaks at Delta 1.60 and 1.68 associ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1968-01-01 00:00:00
abstract：:Dietary n-3 PUFAs have been shown to attenuate T-cell-mediated inflammation. To investigate whether dietary n-3 PUFAs promote activation-induced cell death (AICD) in CD4+ T-cells induced in vitro to a polarized T-helper1 (Th1) phenotype, C57BL/6 mice were fed diets containing either 5% corn oil (CO; n-6 PUFA control) ...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M400028-JLR200
更新日期：2004-08-01 00:00:00
abstract：:Zonation affects liver parenchymal cell function and metabolism as well as nonparenchymal cell activation, but whether VLDL production is zonated has yet to be elucidated. Infection induces enhanced VLDL secretion by the liver. Ex vivo studies were undertaken to examine the liver heterogeneity for VLDL formation and s...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M500003-JLR200
更新日期：2005-05-01 00:00:00
abstract：:Two novel mutations of the low density lipoprotein (LDL)-receptor gene were found in two Italian familial hypercholesterolemia (FH)-heterozygotes. The first mutation was an 18 nucleotide duplication in exon 8 which is preceded by an A-->T transversion. The translation product of the mutant allele was predicted to be a...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1998-07-01 00:00:00
abstract：:3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid (DHCA) and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid (THCA) are metabolized into chenodeoxycholic acid and cholic acid, respectively, through oxidation and cleavage of the terminal three carbons of the side chain. The present study was desig...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1980-02-01 00:00:00
abstract：:Adipose tissue was shown to contain 0.6-1.6 mg of cholesterol per gram wet weight. When expressed per unit of protein or organ mass, fat tissue contains more cholesterol than most other organs or membranes. The cholesterol content of fat tissue increased with the age and weight of the rat. Over 95% of adipose tissue s...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1973-05-01 00:00:00
abstract：:Sphingolipids are ubiquitous components of eukaryotic cells that regulate various cellular functions. In many cell types, a fraction of sphingolipids contain 2-hydroxy fatty acids, produced by fatty acid 2-hydroxylase (FA2H), as the N-acyl chain of ceramide [hydroxyl fatty acid (hFA)-sphingolipids]. FA2H is highly exp...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M800666-JLR200
更新日期：2009-06-01 00:00:00
abstract：:The 3-methyl-branched fatty acid phytanic acid is degraded by the peroxisomal alpha-oxidation route because the 3-methyl group blocks beta-oxidation. In adult Refsum disease (ARD), peroxisomal alpha-oxidation is defective, which is caused by mutations in the gene coding for phytanoyl-CoA hydroxylase in the majority of...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M400064-JLR200
更新日期：2004-07-01 00:00:00
abstract：:ABCG1 and ABCG4 are highly homologous members of the ATP binding cassette (ABC) transporter family that regulate cellular cholesterol homeostasis. In adult mice, ABCG1 is known to be expressed in numerous cell types and tissues, whereas ABCG4 expression is limited to the central nervous system (CNS). Here, we show sig...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/M900250-JLR200
更新日期：2010-01-01 00:00:00
abstract：:Niemann-Pick type C (NPC) disease is a multisystem disorder resulting from mutations in the NPC1 gene that encodes a protein involved in intracellular cholesterol trafficking. Significant liver dysfunction is frequently seen in patients with this disease. The current studies used npc1 mutant mice to investigate the as...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：10.1194/jlr.M600488-JLR200
更新日期：2007-04-01 00:00:00
abstract：:Extracts of urine and serum from children with cholestatic liver disease were analyzed by fast atom bombardment (FAB) mass spectrometry. About half of all spectra showed a peak at m/z 657, compatible with the presence of a glucuronidated cholestenediol sulfate. Separation by ion exchange chromatography before and afte...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1997-05-01 00:00:00
abstract：:The major high density lipoprotein (HDL) apolipoprotein, apoA-I, was knocked out by gene targeting in ES cells to provide a model for the study of HDL metabolism and its relationship to plasma and tissue cholesterol metabolism. HDL and non-HDL cholesterol (HDL-C) were reduced in apoA-I-deficient mice. Feeding a high f...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1997-05-01 00:00:00
abstract：:We have studied the synthesis, modification, and secretion of rat apoE in primary cultures of neonatal aortic smooth muscle cells and adult rat hepatocytes. The cultures were pulsed with [35S]methionine and the intracellular and secreted apoE were immunoprecipitated and analyzed by two-dimensional isoelectric focusing...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1988-07-01 00:00:00
abstract：:The extent of oxidoreduction of the 3 alpha-, 7 alpha- and 12 alpha-hydroxyl groups in bile acids during the enterohepatic circulation in man was studied with the use of [3 beta-3H]-labeled deoxycholic acid and cholic acid, [7 beta-3H]-labeled cholic acid, and [12 beta-3H]-labeled deoxycholic acid and cholic acid. Eac...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1986-02-01 00:00:00
abstract：:Using solid phase systems, the kinetics of binding of monoclonal antibody (LRB 45, IgG2b,kappa) to apoC-I and apoC-I on lipoproteins were investigated. At 25 degrees C, the association constant of LRB 45 antibody to apoC-I (3.56 X 10(6) M-1 X sec-1) was almost three times slower than the association constant LRB 45 an...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1985-07-01 00:00:00
abstract：:The lipids of rat milk, the contents of 9-- 10-day-old rat stomach and intestine, lymph, plasma, and liver were quantitated and their fatty acids were analyzed. Rat milk consists of 97% triacylglycerols, of which 35% of the fatty acids are of medium chain length (C8-C12). However, stomach triacylglycerols show a 25% r...
journal_title：Journal of lipid research
pub_type： 杂志文章
doi：
更新日期：1981-05-01 00:00:00
