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

Human plasma low density lipoprotein (LDL), which binds 0.2% of plasma T4, was shown to interact with the hormone through its protein moiety, apolipoprotein B-100. LDL and LDL2, the major subfraction of LDL, were found to have 3 equivalent binding sites for T4 with Ka = 2.5 x 10(6) M-1. Photoaffinity labeling of LDL with inner ring-labeled [125I]T4, followed by SDS-PAGE or agarose-SDS-PAGE of the labeled products, revealed that apoB-100 and its proteolytic cleavage products, apoB-74 and apoB-26, bound [125I]T4. In the presence of 1 or 10 microM T4, labeling was decreased in 7 separate experiments by 40-53% or 65-86%, respectively, consistent with a Ka of approximately 10(6) M-1. Binding of T4 to apoB-100 associated with VLDL was also demonstrated by photoaffinity labeling. The observed thyroid hormone binding property of lipid-complexed apoB-100 and the knowledge that receptors for the apolipoprotein exist in various tissues suggest a possible physiological role in thyroid hormone transport.
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PMID:Binding of thyroxine to human plasma low density lipoprotein through specific interaction with apolipoprotein B (apoB-100). 249 26

1. Apolipoprotein A-1, isolated from hamster high density lipoprotein, possessed a molecular weight of approximately 27,000. 2. Its amino acid composition differed from human apo A-1 and it contained a higher threonine to serine ratio and a higher methionine and leucine content. 3. The concentration in normal serum was 126.0 +/- 1.9 mg/dl. 4. Apolipoprotein B, isolated from hamster low density lipoprotein consisted of three major components when analyzed by SDS-polyacrylamide gel electrophoresis with Mrs of 635 Kd, 460 Kd and 305 Kd respectively. 5. Hamster apo B possessed a higher aspartic acid to glutamic acid ratio and a higher methionine and valine content than human apo B. 6. The concentration in normal serum was 20.9 +/- 1.0 mg/dl. 7. The apolipoprotein and lipoprotein profile of hamsters fed a high cholesterol diet for 30 days changed considerably. 8. Total serum cholesterol levels increased 7 fold; LDL levels increased 14 fold; HDL levels doubled and total serum triglyceride increased 3 fold. 9. Apo A-1 levels increased by 45% and apo B levels increased 5 fold.
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PMID:Isolation, characterization and quantification of apolipoproteins A-1 and B of the Golden Syrian hamster (Mesocricetus auratus) and modification of their levels by dietary cholesterol. 249 30

The pattern of serum proteins separated by SDS-PAGE is typified by the microprotein apolipoprotein A I which is split from high density lipoprotein by SDS. High density lipoprotein is generally retained by the glomerulus and does not appear in the urine even in glomerulopathies. Thus, apolipoprotein A I is generally absent in the SDS-PAGE protein pattern of renal proteinurias. However, in postrenal hematurias and proteinurias apolipoprotein A I can be found by SDS-PAGE, immunoblotting and Ouchterlony test. Using rabbit anti-human-apolipoprotein A I as primary antibody and alkaline phosphatase-conjugated anti-rabbit immunoglobulins as secondary antibody antibody apolipoprotein A I could be detected even at a 1:128,000 dilution of blood. This means a microhematuria of only 8 microliters blood/l urine theoretically can be identified as postrenal. Unfortunately, apolipoprotein A I is not only visible on the immunoblots of postrenal hematurias and proteinurias but could also be seen in renal proteinurias. Thus, only with reservation can apolipoprotein A I be called a marker of postrenal hematuria and proteinuria. On the other hand, most renal proteinurias can be identified reliably by SDS-PAGE and analysis of apolipoprotein A I is superfluous. Apolipoprotein A I, however, could become useful in the differentiation of microhematurias without proteinuria.
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PMID:[Differentiation of renal and postrenal hematuria and proteinuria with SDS polyacrylamide gel electrophoresis and immunoblotting]. 250 May 60

We describe the development of five murine monoclonal antibodies (14A12, 39A1, 53A9, 73A7, and 128A6) specific to human apolipoprotein[a] (Mr approximately 570,000), and their characterization by a number of procedures including cotitration, competition and inhibition enzyme-linked immunosorbent assays (ELISA), immunoblotting of native lipoproteins and of SDS-solubilized apolipoproteins electrophoresed in polyacrylamide gels, and dot immunobinding assays. The patterns of immunoreactivity of these antibodies were similar. Each reacted in ELISA assays and upon electroimmunoblotting with purified apo[a], with apo[a] liberated by reduction of Lp[a], and with delipidated Lp[a] solubilized in SDS, but by contrast, they reacted with native Lp[a] to a significant degree only upon electroimmunoblotting. No reactivity was seen with LDL-apoB-100 or with other apolipoproteins. The cross-reactivity of these antibodies with the homologous protein, plasminogen, was examined by comparison of the amount of plasminogen or apo[a] required for 50% inhibition of antibody binding to apo[a], and by an ELISA assay. The inhibition assay showed reactivity with plasminogen to be 37- to 50-fold lower than with apo[a], while dot immunobinding showed the lower limit of detection of plasminogen and of apo[a] to be approximately 320 and 31 micrograms, respectively. In an ELISA sandwich assay based on monoclonal antibodies LHLP-1, 14A12, and 53A9, the lower limit of Lp[a] detection (approximately 1 ng/ml protein) was about 100-fold less than that of plasminogen. Chemical modification of apo[a] revealed a significant contribution of arginine residues to the epitopes of 14A12, 39A1, and 53A9. Modification of cysteine residues with iodoacetamide was without effect, thereby distinguishing these antibodies from LHLP-1. Each antibody reacted with the six major size forms of apo[a] (Mr approximately 450,000-750,000) in immunoblots of human sera electrophoresed in SDS-polyacrylamide gels. Marked heterogeneity in apo[a] phenotype was detected and both single and double band phenotypes were observed in a randomized study. Cotitration and competition binding studies showed varying degrees of interaction between all five epitopes, with the exception of 128A6 which appeared to be independent of 39A1 and 53A9 (and vice versa). These data suggest that our five monoclonal antibodies recognize epitopes on apolipoprotein[a] that are exposed and accessible on the native Lp[a] particle. We conclude that our monoclonal antibodies recognize a specific region of apo[a], and that this region undergoes a conformational change upon adsorption of Lp[a] to plastic thereby diminishing epitope recognition.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Characterization of five mouse monoclonal antibodies to apolipoprotein[a] from human Lp[a]: evidence for weak plasminogen reactivity. 252 88

In studies of cebus monkey plasma lipoproteins, we have used an ultracentrifugally generated density gradient to isolate two distinct species of low density lipoproteins (LDL). Compositional analyses revealed that each of the ultracentrifugally isolated fractions was enriched in cholesteryl esters and contained a single apolipoprotein which in terms of its mobility on SDS gels corresponded to apolipoprotein B-100, the major apolipoprotein of human LDL. Hydrodynamic measurements carried out in the analytical ultracentrifuge showed that F1.20 values were 30.0 for LDL1 and 23.5 for LDL2. In a solution of density 1.0069 g/ml, the sedimentation rates were 5.9 and 7.2 S for LDL1 and LDL2, respectively. In addition to sedimentation velocity data, we describe a new approach for using these same data to obtain calculated values for molecular weight. The hydrated densities calculated for the two fractions were 1.033 and 1.045 g/ml and calculated molecular weights were 3.08 million for LDL1 and 2.42 million for LDL2. Hydrated density values were in excellent agreement with those calculated from compositional data. Electron microscopy data showed that LDL1 had a larger mean diameter of 26.7 nm than LDL2 which had a diameter of 19.3 nm. Native gel electrophoretic analyses of the two LDL fractions in 3.5% acrylamide showed that, consistent with its size, LDL1 had slower mobility than LDL2.
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PMID:Low density lipoprotein heterogeneity in the cebus monkey. 276 May 40

1. Equine lipoproteins were isolated from plasma by density gradient ultracentrifugation and apolipoprotein composition determined by SDS-polyacrylamide gel electrophoresis. 2. VLDL and IDL were present at low concentration (0.2 mg/ml). Two apoB components of Mr corresponding to human apoB-100 and one apoB-48-like component were represented in VLDL fraction. 3. LDL-1 and LDL-2 subfractions have displayed an almost equal concentration (0.4 mg/ml). Two apoB-100-like components were the major apolipoproteins in each fraction. Small amounts of apoB-48-like component were detectable in LDL-1 and LDL-2. 4. HDL-2 represented a major class of equine lipoproteins (1.8 mg/ml). ApoA-1-like component was the dominant protein in HDL-1, HDL-2 and HDL-3. Dimeric apoA-II-like components were slightly represented in HDL subfractions. 5. HDL-3 displayed the same apolipoprotein pattern as HDL-1 and HDL-2, but two further minor proteins of Mr 20,000 and 14,000 were detected. 6. VHDL represented a minor class of lipoprotein (0.2 mg/ml). ApoA-I-like component was the major apolipoprotein of VHDL. Small amounts of apoA-IV-like, apoE-like, and Mr 55,000 protein were detectable. 7. ApoC-like of Mr lower than 10,000 was represented in all equine lipoprotein classes.
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PMID:Lipid and apolipoprotein distribution as a function of density in equine plasma lipoprotein. 277 30

Apolipoprotein E-free high density lipoproteins (HDL) bind to various cells and cell membrane preparations, with properties typical of ligand-receptor interactions. In order to further characterize the binding sites and to investigate the functional role of binding, a chemically modified HDL without the specific binding properties would be highly desirable. We have reacted human HDL3 with tetranitromethane, a relatively specific nitrating reagent for tyrosine residues, in 50 mM Tris HCL buffer, pH 8.0, and at a reagent concentration 10 times the molar excess of tyrosine residues. The resulting nitrated HDL3 completely lost its ability to bind to high affinity saturable binding sites of rat liver plasma membranes, as determined by competitive binding with 125I-labeled HDL3, and also by direct binding assays using 125I-labeled nitrated HDL3. Although nitrated HDL3 did not bind to the high affinity saturable binding sites, it bound to the membranes, but the binding was not saturable, and was not competed for by unlabeled nitrated HDL3. On agarose gel electrophoresis, pH 8.6, the nitrated HDL3 moved ahead of the control HDL3, indicating an increase in negative charges in the molecule. No difference in size was noted in the nitrated HDL3 when analyzed either by negative stain electron microscopy or by gel filtration chromatography. Spectroscopic analysis of the nitrated HDL3 at pH 8.0 revealed a prominent absorption with maximum at around 360 nm, but none in the region expected for nitrotyrosine residues. At pH 10.0, however, the nitrated HDL3 showed an absorption band with a maximum at around 440 nm, possibly related to nitrotyrosine residues. Nitrotyrosine was detected in the nitrated HDL3 on amino acid analysis. Comparison of the amino acid analysis of the nitrated HDL3 and control HDL3 showed no difference in composition of any of the amino acids except tyrosine; tyrosine content was reduced more than 90% in the nitrated HDL3. SDS-polyacrylamide gel electrophoresis analysis of apoproteins of nitrated HDL3 revealed changes in apolipoprotein profile. Bands corresponding to the apolipoproteins of the starting HDL3 almost disappeared and a series of new bands appeared at the high molecular weight region of the gel, indicating extensive cross-linking of apolipoproteins during the reaction. In addition, a substantial amount of phospholipids and cholesteryl esters, but not unesterified cholesterol, was found covalently linked, possibly through the unsaturated centers of the fatty acid chains, to apolipoproteins.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Modification of human high density lipoprotein (HDL3) with tetranitromethane and the effect on its binding to isolated rat liver plasma membranes. 299 64

Serum PGI2 stabilizing factor (PSF) was purified from human serum to a single protein with a molecular weight of 28,000 D by SDS-PAGE. Analyses of NH2-terminal sequence (32 residues), COOH-terminal sequence (3 residues) and the composition of amino acids disclosed its homology with human apolipoprotein A-I (Apo A-I), a major apolipoprotein of HDL. Apolipoprotein A-II, C-I, C-II, C-III, D and E, as well as LDL, and VLDL did not possess this activity. The alpha-helix structure of Apo A-I is necessary for the binding of PGI2. HDL and nascent HDL reconstituted from Apo A-I and phospholipid significantly prolonged the half-life of PGI2. PGI2 stabilization by HDL and Apo A-I may be an important protective action against the accumulation of platelet thrombi at sites of vascular damage. The beneficial effect of HDL in the prevention of coronary artery disease may be partly due to this action.
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PMID:Serum prostacyclin stabilizing factor is identical to apolipoprotein A-I (Apo A-I). A novel function of Apo A-I. 304 70

The two major apolipoproteins of badger serum, apoA-I and apoB, have been isolated and characterized. Apolipoprotein A-I was the principal protein of badger lipoproteins with density 1.063-1.21 g/ml and, in addition, was present in the lipoprotein class with density 1.006-1.063 g/ml. This apolipoprotein displayed an Mr of approximately equal to 27,000-28,000 and was polymorphic (three prominent isoproteins) on isoelectric focusing, with pI values in the range 5.38-5.55. The amino acid profile of badger apoA-I generally resembled those reported in the literature for similar proteins in dog and man. Amino terminal sequence analysis up to the 40th residue showed close homology between the badger, dog, and human proteins; badger and dog apoA-I differed only at residue 24, at which serine in the dog was substituted by glycine in the badger. Several forms of apolipoprotein B were present in badger lipoproteins with densities less than 1.063 g/ml, their distribution and apparent Mr being unaffected by the presence or absence of 1 mM PMSF during the isolation process. The components of higher Mr were essentially represented by a protein with Mr approximately equal to 530,000-550,000 (apoBH) as determined by SDS-polyacrylamide electrophoresis; this protein predominated both in lipoproteins with d 1.006-1.063 g/ml and in those with d less than 1.006 g/ml. In addition, proteins with approximate Mr values of 490,000, 450,000, and 190,000, respectively, were present as minor components. A lower Mr form (250,000, apoBL), was observed only in lipoproteins with d less than 1.006 g/ml.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Isolation and characterization of the major plasma apolipoproteins, A-1 and B, in the European badger, Meles meles. 308 34

Heretofore, immunologic reagents used to define and quantify human Lp(a) have been polyclonal in origin and therefore heterogeneous in antigenic specificity. We report here the isolation of a mouse monoclonal antibody, LHLP-1, monospecific for Lp(a). The antigen reactive with LHLP-1 was expressed in both lipoprotein Lp(a) as well as apolipoprotein Lp(a) delipidated by SDS treatment; however, disulfide reduction of apolipoprotein Lp(a) inhibited LHLP-1 reactivity. The antigen reactive with LHLP-1 on Lp(a), therefore, appears not to require lipid for expression of its conformationally dependent (disulfide-inhibitable) epitope. Antigen reactivity was virtually absent in the apoB and other proteins contained in very low density, low density, and high density lipoprotein particles. Immunologic quantification of Lp(a) in individual serum samples with a rabbit reference antiserum or LHLP-1 showed good correlation. We conclude that the monoclonal antibody LHLP-1 identifies an antigen unique to Lp(a) and that this antibody may therefore be useful in the further characterization and measurement of human Lp(a).
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PMID:Identification of a mouse monoclonal antibody, LHLP-1, specific for human Lp(a). 316 Aug 1


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