Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the association of apolipoprotein (a) [apo(a)]polymorphism with coronary heart disease in Chinese Han nationality. The effects of the apo(a) phenotypes on lipoprotein [Lp (a)], total cholesterol (TC), high density lipoprotein cholesterol (HDL), and triglyceride (TG) levels were also investigated. The CHD group consisted of 105 patients (85 were survivors from previous myocardial infarction and 20 had > or = 75% narrowing in at least one of the major coronary arteries found by coronary angiography). The control group included 102 healthy individuals who had no symptoms and clinical signs of cardiovascular diseases. Apo(a) phenotype was performed by SDS-polyacrylamide gel electrophoresis (PAGE) under reducing conditions followed by immunoblotting. Determination of (a) Lp(a) and other lipoproteins were also performed. The apo(a) low molecular weight phenotypes (B, S1, S2) were more frequent in the CHD patients than in the healthy individuals (30.5% vs 15.7%, P < 0.05). Lp(a) concentrations were significantly higher in the patients than in the controls (257 +/- 225 mg/L vs 145 +/- 157 mg/L, P < 0.001). The results from stepwise logistic regression analysis indicated that apo(a) phenotype was a significant predictor of CHD, independent of TC, LDL-C and HDL-C. But apo(a) molecular weight was inversely related to Lp(a) levels. The apo(a) low molecular weight phenotypes associated with elevated Lp(a) levels was a primary genetic risk factor for CHD in Han Chinese.
 ...
PMID:[Apolipoprotein (a) polymorphism in relation to coronary heart disease in Chinese Han nationality]. 869 71

A rapid method to obtain large amount of VLDL and LDL by ultracentrifugation is described. The mixture of VLDL and LDL was isolated and concentrated from plasma by an ultracentrifugation at 265 000 g for 2 h. VLDL and LDL were separated and purified by a further ultracentrifugation at 265 000 g for 3 h. This method combines the advantages of both sequential flotation ultracentrifugation and density gradient ultracentrifugation. It can process a large volume of plasma in a short time. The purity of isolated VLDL and LDL was confirmed by the lipoprotein electrophoresis on agarose gel and PAGE and by the apolipoprotein electrophoresis on SDS-PAGE. This rapid economical method is of great value in practical application.
 ...
PMID:Rapid isolation of large amount of plasma VLDL and LDL by a two step ultracentrifugation. 873 22

This study was designed to determine whether an enhanced intestinal synthesis of apolipoprotein (apo) A-I is associated with the hyperapolipoproteinemia observed in copper-deficient rats. Male weanling Sprague-Dawley rats were assigned to two dietary treatments, Cu deficient (0.6 ppm Cu) and Cu adequate (6.0 ppm Cu) for 6 weeks. In vivo studies were then performed after rats were injected with a flooding dose of 150 microM [3H]phenylalanine (PHE, 50 microCi/ml/100 g body wt). Three rats from each treatment were sacrificed at 5, 10, 15, 30, and 60 min postinjection. The small intestine was rapidly rinsed and frozen in liquid N2. In vitro studies were performed by labeling freshly isolated 6-cm segments from duodenum, jejunum and ileum with [3H]PHE (33 microCi/ml, 49.7 Cl/mmol) in PHE-free minimum essential medium for 7 and 14 min. In vivo and in vitro intestinal samples were sonicated, solubilized in 1% Triton X-100, and centrifuged to provide the detergent soluble fraction for the isolation of nascent apo A-I and total protein. Radioactivities associated with nascent apo A-I isolated by immunoprecipitation and SDS-PAGE, and with total protein precipitated by trichloroacetic acid, were measured to determine the influence of Cu deficiency on nascent apo A-I and total protein synthesis. In the Cu-deficient small intestine, the synthesis of total protein was measured only in the duodenum and was enhanced after 1 hr for the in vivo studies. Moreover, total protein synthesis was enhanced at both 7 and 14 min of the in vitro studies for all three small intestinal segments of the Cu-deficient rats. Apo A-I synthesis was measured only at the jejunum and was also enhanced by Cu deficiency in the in vitro studies. Thus, an increase in intestinal apo A-I synthesis may contribute to the elevated plasma apo A-I level in Cu-deficient rats.
 ...
PMID:Copper deficiency increases total protein and apolipoprotein A-I synthesis in the rat small intestine. 875 96

Structures of apoE(263-286) and apoE(267-289) have been determined in aqueous solution containing 90-fold molar excess of perdeuterated sodium dodecyl sulfate by CD and 1H NMR. Conformations were calculated by distance geometry based on 370 and 276 NOE distance restraints, respectively. RMSD for superimposing the region 265-284 from an ensemble of 41 structures for apoE(263-286) is 0.64 +/- 0.17 A for backbone atoms (N, C alpha, C = O) and 1.51 +/- 0.13 A for all atoms. The backbone RMSD for an ensemble of 37 structures for apoE(267-289) is 0.74 +/- 0.21 A for the region 268-275 and 0.34 +/- 0.10 A for the region 276-286. A two-domain structure was found for apoE(267-289) with the C-terminal half adopting a very well defined helix and the N-terminal segment 268-275 a less well defined helix, suggesting that the N-terminus may weakly bind to SDS. For apoE(263-286), an amphipathic helix-bend-helix structural motif was found with all hydrophobic side chains on the concave face. The existence of a bend around residues Q273 to G278 is consistent with their temperature coefficients of amide protons as well as secondary shifts of alpha-protons. Comparison of the structures of the two peptides revealed that the enhanced binding of apoE(263-286) to lipid could be attributed to the formation of a hydrophobic cluster consisting of residues W264, F265, L268, and V269. Aromatic side chains are proposed to be especially important in anchoring apolipoprotein fragments to micelles.
 ...
PMID:Conformations of human apolipoprotein E(263-286) and E(267-289) in aqueous solutions of sodium dodecyl sulfate by CD and 1H NMR. 875 91

We describe a new method for the rapid fractionation of plasma lipoproteins, which makes use of a new non-ionic, iodinated, density gradient medium, iodixanol, commercially available as Optiprep(TM). The method is simple: plasma or serum is mixed with iodixanol followed by centrifugation in a vertical or near vertical rotor. Separation of VLDL, LDL and HDL can be achieved in 3 h and the lipoprotein fractions are comparable in density and composition with those prepared using conventional salt based gradients. Each class of lipoprotein can be removed in a single fraction, or a profile of lipoprotein distribution can be obtained using a gradient fractionator. Because the medium is inert, fractions from the gradient can be analysed by agarose gel electrophoresis or assayed for lipid content or apolipoprotein composition by SDS-PAGE without removing the iodixanol. Small differences in electrophoretic mobility of HDL and LDL across several gradient fractions suggest that subfractionation of these classes may occur. The new method is simple, rapid and versatile with potential application for preparation of lipoproteins and for analysis of lipoprotein profiles in the research or clinical laboratory.
 ...
PMID:A novel method for the rapid separation of plasma lipoproteins using self-generating gradients of iodixanol. 880 May

We have produced gene knockout mice by targeted disruption of the apobec-1 gene. As recently reported by Hirano et al. (Hirano, K.-I., Young, S. G., Farese, R. V., Jr., Ng, J., Sande, E., Warburton, C., Powell-Braxton, L. M., and Davidson, N. O. (1996) J. Biol. Chem. 271, 9887-9890), these animals do not edit apolipoprotein (apo) B mRNA or produce apoB-48. In this study we have performed a detailed analysis of the lipoprotein phenotypic effects of apobec-1 gene disruption that were not examined in the previous study. We first analyzed the plasma lipoproteins in knockout animals with a wild-type genetic background. Although there was no difference in plasma cholesterol between apobec-1(-/-), +/-, or +/+ mice, there was a marked (176%) increase in plasma apoB-100, from 1.8 +/- 1.2 mg/dl in apobec-1(+/+) mice to 2.7 +/- 0.6 mg/dl in apobec-1(+/-) and 5.0 +/- 1.4 mg/dl in apobec-1(-/-) mice. Plasma apoE was similar in these animals. By fast protein liquid chromatography (FPLC) analysis, there was a significant decrease in plasma high density lipoprotein (HDL) cholesterol in apobec-1(-/-) mice. We further fractionated the plasma lipoproteins into d < 1.006, 1.006-1.02, 1.02-1.05, 1.05-1.08, 1.08-1.10, and 1.10-1.21 g/ml classes, and found a marked (30-40%) reduction in the cholesterol and protein content in the (d 1.08-1.10 and 1.10-1.21) HDL fractions, corroborating the FPLC data. SDS-gel analysis revealed an absence of apoB-48, an increase in apoB-100 in the very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions, and a small decrease in apoA-I in the HDL fractions in the apobec-1(-/-) samples. We next raised the basal plasma apoB levels in the apobec-1(-/-) animals by cross-breeding them with human apoB transgenic (TgB) mice. The plasma apoB-100 was 3-fold higher in apobec-1(-/-)/TgB+/- mice (26.6 +/- 18.3 mg/dl) than in apobec-1(+/+)/TgB+/- mice (9.8 +/- 3.9 mg/dl, p < 0.05). The apobec-1(-/-)/TgB+/- mice had a plasma cholesterol levels of 170 +/- 28 mg/dl and triglyceride levels of 106 +/- 31 mg/dl, which are 80% and 58% higher, respectively, than the corresponding values of 94 +/- 21 mg/dl and 67 +/- 11 mg/dl in apobec+/+/TgB+/- mice. By FPLC, the apobec-1(-/-)/TgB+/- animals developed markedly elevated plasma LDL cholesterol (518.5 +/- 329.5 microg/ml) that is 373% that of apobec1(+/+)/TgB+/- mice (139.0 +/- 87.0 microg/ml) (p < 0.05). The elevated plasma triglyceride was accounted for mainly by a 97% increase in VLDL triglyceride in the apobec1(-/-)/TgB+/- mice. We conclude that apobec-1(-/-) animals have a distinctive lipoprotein phenotype characterized by significant hyperapoB-100 and HDL deficiency in mice with a wild-type genetic background. Furthermore, the abolition of apoB mRNA editing elevates plasma total cholesterol and LDL cholesterol in apobec-1(-/-) animals with a TgB background. Finally, to exclude the possibility that absence of apoB mRNA editing was a secondary effect of chronic Apobec-1 deficiency, we treated apobec-1(-/-) mice with a replication-defective mouse Apobec-1 adenoviral vector and found that we could acutely restore apoB mRNA editing in the liver. These experiments indicate that Apobec-1 is an essential component of the apoB mRNA editing machinery and absence of editing in the knockout animals is a direct consequence of the absence of functional Apobec-1.
 ...
PMID:Complete phenotypic characterization of apobec-1 knockout mice with a wild-type genetic background and a human apolipoprotein B transgenic background, and restoration of apolipoprotein B mRNA editing by somatic gene transfer of Apobec-1. 882 35

Human apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins (HDL) where it defines the particle structure and stability and functions as the main activator of the enzyme lecithin:cholesterol acyltransferase (LCAT). ApoA-I is expressed in the liver as a preproprotein that is targeted to the endoplasmic reticulum for secretion; in plasma, an unknown protease removes the six amino acid long propeptide. In this study, the cDNA coding the human proapoA-I was cloned into an Escherichia coli vector; the overexpressed protein was purified to 99% homogeneity and was extensively characterized together with mature apoA-I purified from plasma. SDS-PAGE, mass spectrometry, and Edman sequence analysis showed that the initial Met residue needed for translation in E. coli is posttranslationally removed from the N-terminal sequence of the proapoA-I. The structural and functional analyses were carried out on the lipid-free and the lipid-bound proteins. ProapoA-I self associated, interacted with dimyristoyl phosphatidylcholine vesicles, and formed secondary structures very similar to the lipid-free apoA-I. Reconstituted HDL particles made with two initial molar ratios of palmitoyloleoyl phosphatidylcholine/cholesterol/apolipoprotein/Na-cholate had identical particle sizes and distributions when apoA-I or proapoA-I were used. Particles having diameters of 79 A and 98 A, containing two apoA-I or proapoA-I molecules per particle, were isolated and characterized. The particles contained the same amounts of alpha-helical structure, had very similar fluorescence properties, and activated LCAT equally well. We conclude that proapoA-I expressed and purified from E. coli is functionally and structurally indistinguishable from mature apoA-I purified from plasma when analyzed in vitro. Therefore, this recombinant proapoA-I and mutants derived from it will be important sources of protein for analyzing apoA-I structure and function, as well as for studies of proapoA-I processing.
 ...
PMID:High yield overexpression and characterization of human recombinant proapolipoprotein A-I. 882 24

Density gradient ultracentrifugation and anion-exchange chromatography combination were effective for the purification of the eel vitellogenin from the plasma of estradiol-treated eels. The vitellogenin was very high density glycolipoprotein (P = 1.27 g/ml) and its apolipoprotein was M(r) 196 k in both reduced and non-reduced conditions by SDS-PAGE. The major lipid component was phospholipid. The N-terminal amino-acid sequence of the vitellogenin was as follows: (Ac)Thr-Pro-Ala-Leu/Ala-Asp-Tyr. Amino-acid composition of the eel vitellogenin was similar to those of other teleosts. The protease activity appeared in the trypsinized vitellogenin, but was not detected in the purified vitellogenin. The protease was separated from the used trypsin and the other cleaved vitellogenin by a dextran sulfate cellulose column. The molecular weight of the protease was determined by zymogram using SDS-polyacrylamide gel containing casein and was 50 k. It was concluded that the eel vitellogenin possesses the protease activity as a latent form.
 ...
PMID:Protease activity appeared after trypsin treatment of the purified vitellogenin from eel Anguilla japonica. 882 6

Plasma levels of lipoprotein(a) (Lp(a)) vary over 1000-fold between individuals and are determined by the gene for its unique apolipoprotein, apo(a), which has greater than 100 alleles. Using primary baboon hepatocyte cultures, we previously demonstrated that differences in the ability of apo(a) allelic variants to escape the endoplasmic reticulum (ER) are a major determinant of Lp(a) production rate. To examine the reason for these differences, the folding of newly synthesized apo(a) was analyzed in pulse-chase experiments. Samples were harvested in the presence of N-ethylmaleimide to preserve disulfide-bonded folding intermediates, and apo(a) was analyzed by immunoprecipitation and SDS-polyacrylamide gel electrophoresis. Apo(a) required a prolonged period (30-60 min) to reach its fully oxidized form. Multiple folding intermediates were resolved, including a disulfide-linked, apo(a)-containing complex. Unexpectedly, all allelic variants examined showed similar patterns and kinetics of folding. Even "null" apo(a) proteins, which are unable to exit the ER, appeared to fold normally. The ER glucosidase inhibitor, castanospermine, prevented apo(a) secretion, but did not inhibit folding. This suggests that an event which is dependent on trimming of N-linked glucoses, and which occurs after the folding events detectable in our assay, is required for apo(a) secretion. Differences in the ability to undergo this event may explain the variable efficiency with which apo(a) allelic variants exit the ER.
 ...
PMID:Influence of allelic variation on apolipoprotein(a) folding in the endoplasmic reticulum. 903 May 68

A novel apoprotein of an apparent molecular mass of 86 kDa in its unreduced form was identified in human triglyceride-rich lipoproteins. This protein was purified and the amino acid sequence of six proteolytic fragments was found to overlap with that of the factor H-related proteins. In parallel we identified the cDNA encoding a new complement factor H-related protein, termed FHR-4. The sequences of the new apoprotein overlapped with that of the FHR-4 protein. Similar to the previously described factor H-related proteins, FHR-4 contains a hydrophobic signal sequence followed by a stretch of five repetitive elements termed short consensus repeats. Recombinant FHR-4 protein was expressed in the baculovirus system and has an apparent molecular mass of 42 kDa. In addition a 84-kDa dimeric form of the recombinant FHR-4 was detected. Using an immunoaffinity column with antibodies raised against the recombinant FHR-4, we isolated a 86-kDa protein from human plasma. The different molecular mass of the recombinant FHR-4 and the dimeric FHR-4 in plasma is due to different carbohydrate moieties. The 86-kDa plasma protein and the novel apolipoprotein had identical mobility on SDS-polyacrylamide gel electrophoresis analysis and reacted with antisera raised against the reFHR-4 and the purified apoprotein. In conclusion, we have identified a novel factor H-related protein, FHR-4, in human plasma and demonstrate that this protein is present in triglyceride-rich lipoproteins in a dimeric form. This observation provides an intriguing new aspect on possible function(s) of this novel protein and the other factor H-related proteins.
 ...
PMID:The human factor H-related protein 4 (FHR-4). A novel short consensus repeat-containing protein is associated with human triglyceride-rich lipoproteins. 903 72


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>