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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycoprotein-containing extracts were obtained from thoracic arteries of embryonic chicks by sequential treatment involving 6 M guanidinium chloride, purified bacterial collagenase, and 6 M guanidinium chloride plus 50 mM dithiothreitol. Two major glycopolypeptides, designated G1 and G2, having apparent mol. wts. of 140,000 and 130,000 respectively were detected by SDS/polyacrylamide gel electrophoresis. Equilibrium density gradient ultracentrifugation demonstrated G1 and G2 to be glycoproteins and not proteoglycans or glycosaminoglycans. Amino acid analysis of a glycoprotein-enriched fraction confirmed the non-collagenous nature of G1 and G2. The highly insoluble nature of these glycoproteins suggests that these species are intimately associated with the extracellular matrix. Glycoproteins of similar size were also extracted from wing tendons indicating that G1 and G2 may be common to the elastic tissues of the chick.
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PMID:Two major non-collagenous glycoproteins in embryonic chick arteries. 621 56

Immunoprecipitates of the T3 antigen prepared from HPB-ALL cells by using the monoclonal antibody UCH-T1 were analysed by SDS-polyacrylamide gel electrophoresis. Cells which had been biosynthetically labelled for up to 4 h gave a major polypeptide of mol. wt. 19 000 plus two weaker, more diffuse bands of mol. wts. 21 000 and 23 000, whereas surface labelled cells gave a prominent band of mol. wt. 19 000, a major band of 21 000 and a weaker diffuse band of approximately 26 000. As judged from their sensitivity to proteinase-K digestion, all the above polypeptides possess a transmembrane orientation. Digestion with endoglycosidases H and F (endo-H and endo-F), and tunicamycin treatment indicate that all the polypeptides, except that of 19 000 mol. wt. are N-glycosylated. The 21 000 and 23 000 mol. wt. chains possess both immature and mature oligosaccharide units, whereas the 26 000 mol. wt. band apparently has mature units only. Pulse chase experiments combined with digestion by endo-F and endo-H suggest that the N-glycosylated polypeptides are derived from two polypeptides of mol. wts. 14 000 and 16 000. It is concluded that the T3 antigen is derived from three different non-glycosylated polypeptides two of which are subsequently N-glycosylated to give the 21 000, 23 000 and 26 000 forms. The cell surface T3 antigen most probably comprises at least two distinct, non-covalently associated polypeptides, but the number and types of polypeptides giving rise to the whole molecule and whether different complexes exist is at present unclear.
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PMID:Biosynthesis and molecular nature of the T3 antigen of human T lymphocytes. 622 78

The Fc gamma receptor of guinea-pig peritoneal macrophages was purified by affinity chromatography by using rabbit IgG or guinea-pig IgG2 coupled to Sepharose. Lysates prepared by treatment of 125I-labeled macrophages with NP-40 were first applied to BSA-Sepharose and then to IgG-Sepharose and eluted with 0.5 M acetic acid containing 1% NP-40. The specific binding was determined by interaction of the 125I-labeled receptor with IgG-Sepharose in the presence and absence of soluble IgG. The specific binding of the purified receptor was 42-82%. Interactions of the purified receptor with IgG-Sepharose were equally well inhibited by soluble rabbit IgG or guinea-pig IgG2, but not by F(ab')2 fragments. Inclusion of NP-40 in the buffer used in the assay reduced nonspecific binding of the receptor to the affinity gels. The purified receptor can be stored for 20 days at 4 degrees C without a significant loss of the specific binding activity. Analysis of the receptor by SDS-polyacrylamide gel electrophoresis, under nonreducing and reducing conditions, revealed two major peaks of radioactivity corresponding to mol. wts of about 50,000 and 25,000, and one very minor peak corresponding to a mol. wt of about 30,000. The results obtained suggest that the protein of the second major peak is a product of the dissociation of the protein of the first major peak rather than a product of its reduction by 2-mercaptoethanol.
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PMID:Guinea-pig peritoneal macrophage receptor for IgG--II. Purification of the receptor and its partial characterization. 622 19

A genetically defective form of C1q was purified from the sera of patients suffering from an immune complex related disease and who were homozygous for the defect. The defective C1q was haemolytically inactive and did not bind to immune aggregates or IgG-Sepharose. It showed the following similarities to the normal C1q molecule: a high glycine content and the presence of hydroxyproline and hydroxylysine; subunits with apparent mol. wts of 70,000 and 56,000, when examined by SDS-polyacrylamide gel electrophoresis under non-reducing conditions; preferential incorporation of 125I-label into only one of the types of chain present in the molecule, in a manner similar to that found for the C-chain of normal C1q. However, the defective molecule had an apparent mol. wt of approximately 155,000 in non-dissociating conditions, which is approximately one-third of the mol. wt of the normal molecule. Also, the material in the defective molecule preparation which corresponded, on the basis of mol. wt, to the disulphide-linked A-chain-B-chain dimer of normal C1q differed from that found in the normal molecule in that it did not appear to be sensitive to reducing agents. Collagenase and pepsin treatment of specific immunoprecipitates containing the radiolabelled defective molecule indicated that it is, like the normal molecule, composed of collagenous and non-collagenous domains.
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PMID:Characterization of a non-functional form of C1q found in patients with a genetically linked deficiency of C1q activity. 632 98

The interaction of phytohaemagglutinin (PHA) with the human T lymphocyte antigen receptor (Ti) was explored. Nonidet-P40 lysates of surface-labelled HPB-ALL cells were immunoprecipitated with PHA, using a rabbit anti-(PHA)-serum, as well as clonotypic monoclonal antibodies (H1-2D4 and T40/25) and a rabbit antiserum (R-43) against Ti. One- and two-dimensional SDS-polyacrylamide electrophoresis under reducing and non-reducing conditions showed that both the clonotypic antibodies and PHA precipitated a disulphide cross-linked heterodimer having a mol. wt. of approximately 79 000 (unreduced) and a comprising subunits of mol. wts. approximately 50 000 and 39 000 (reduced). Further evidence that PHA binds Ti was obtained by (i) cross-immunodepletion with H1-2D4 and PHA; (ii) immunoprecipitation with H1-2D4 of a glycoprotein fraction specifically eluted from a PHA immunoprecipitate; (iii) immunoprecipitation with PHA of a solubilised H1-2D4 immunoprecipitate; (iv) 2-D (non-equilibrium pH gradient electrophoresis/SDS) analyses of H1-2D4 and PHA immunoprecipitates, indicated that H1-2D4 and PHA recognise coincident beta polypeptides. PHA also binds a Ti-like disulphide cross-linked heterodimer on tonsil lymphocytes and two other T-cell leukaemias (HUT-78 and J6). The data further suggest that PHA and R-43 recognise a subpopulation of Ti molecules on HPB-ALL cells that are not bound by H1-2D4, suggesting that there may be at least two forms of Ti. Similar experiments indicate that Concanavalin A (Con A) and wheat germ agglutinin (WGA) also probably bind Ti, whereas Helix pomatia agglutinin (HPA) does not.
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PMID:Phaseolus vulgaris phytohaemagglutinin (PHA) binds to the human T lymphocyte antigen receptor. 633 29

Electrophoresis of cornified cell extracts of 2-day-old rats, using SDS polyacrylamide gels copolymerized with alpha-casein or gelatin with or without plasminogen, was performed. Both Tris-HCl buffer soluble protein and KSCN solubilized protein contained a number of hydrolases for alpha-casein and/or gelatin, but PA (mol. wts 57 and 50K) was found only in the KSCN extract. The pH dependency, substrate specificity and mol. wt of plasminogen-independent proteinases were comparatively determined and DFP inhibition tested. This simple technique helped to identify the presence of several proteinases and to characterize them in partially purified epidermal extracts.
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PMID:Detection and characterization of epidermal proteinases by polyacrylamide gel electrophoresis. 636 28

Monoclonal and polyclonal L1 antibodies react by indirect immunofluorescence with the cell surface of cultured tetanus toxin-positive neurons from post-natal cerebella of mice, but not with glial fibrillary acidic protein-positive astrocytes, O4 antigen-positive oligodendrocytes or fibronectin-positive fibroblasts or fibroblast-like cells. During cerebellar development L1 antigen is detectable on tetanus toxin-positive cells as early as embryonic day 13 after 3 days in culture. In sections of the early post-natal cerebellum, L1 antigen is found on pre-migratory neurons in the internal, but not in the external part of the external granular layer. In the adult cerebellum, L1 antigen is predominantly localized in the molecular layer and around Purkinje cells. Fibers in white matter and the granular layer are also L1 antigen-positive. Granule cell bodies and synaptic glomeruli are weakly antigen-positive. Several cell lines derived from neuroblastoma C1300 also express L1 antigen. The antigen is not detectable by enzyme-linked immunosorbent assay in tissue homogenates of liver, kidney, lung, heart, sperm or thymus. With polyclonal L1 antibodies, cross-reactive determinants are found in brains of rat, guinea pig, hamster, chicken, rabbit and man, but not in frog, while monoclonal antibody reacts detectably only with mouse brain. The molecular species recognized by both monoclonal and polyclonal antibodies display two prominent bands by SDS-PAGE under reducing and non-reducing conditions with apparent mol. wts. of 140 and 200 kd. L1 antigen isolated from cultured cerebellar cells consists mainly of a band in the 200-kd range and a faint one at 140 kd. L1 antigen from neuroblastoma N2A shows two bands with slightly higher apparent mol. wts. All molecular forms of L1 antigen can be labeled by [3H]fucose and [3H]glucosamine. Ca2+-independent re-aggregation of cerebellar cells from early post-natal C57BL/6J mice and of the continuous cell line N2A derived from the murine neuroblastoma C1300 is inhibited by Fab fragments of the polyclonal, but not of monoclonal antibody, both of which are known to react with the surface membrane of these cells.
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PMID:Immunocytological and biochemical characterization of a new neuronal cell surface component (L1 antigen) which is involved in cell adhesion. 636 20

We describe the purification of a novel hematopoietic growth factor from conditioned medium of a transformed macrophage cell line. The factor, termed chicken myelomonocytic growth factor (cMGF) stimulates the growth of chicken myeloblasts transformed by myb oncogene-containing retroviruses and induces the formation of macrophage colonies in uninfected chick bone marrow cultures. The biological activity of the factor is destroyed by trypsin and by reducing reagents but not by SDS. Analysis of crude conditioned medium on non-reducing SDS gels reveals two active species of cMGF with mol. wts. of 23 and 27 kd. Incubation of radioiodinated partially purified cMGF with myeloblasts demonstrates the specific binding of 23- and 27-kd components under non-reducing, and 25- and 29-kd components under reducing conditions. Glycosylation inhibition experiments indicate that the larger molecules represent glycosylated forms of a single protein moiety. The 27-kd species has been purified to homogeneity (80 000-fold enrichment) and exerts its half maximal activity at 2 X 10(-12) M and its maximal activity at 3 X 10(-11) M. Antibodies prepared to purified cMGF completely neutralize the growth-stimulating activity of the factor.
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PMID:Purification and characterization of cMGF, a novel chicken myelomonocytic growth factor. 639 86

An efficient method is described for the isolation of highly purified, IgG-free and stable guinea-pig serum C1q. The procedure includes the chromatography of EDTA-treated serum (25 mM EDTA) on CM- and DEAE-cellulose followed by gel filtration on ACA 34-Ultrogel whereby ammonium sulfate precipitation was used for concentration. The final product stored in a glycerol containing buffer was purified 700-fold with a yield of approximately 50%. It was judged to be homogeneous by several criteria including SDS-PAGE, analytical ultracentrifugation, gel filtration and immunoprecipitation. The protein has a sedimentation rate of 11.3 S and consists of three distinct polypeptide chains A, B and C with mol. wts of 30,200, 28,200 and 24,000. Amino acid analysis revealed a content of 4.42% hydroxyproline, 1.81% hydroxylysine and 18.7% glycine. In contrast to human serum C1q a very low content of cysteine residues was detected. SDS-PAGE analysis performed in the absence of 2-mercaptoethanol but in the presence of 5-10% SDS revealed clearly that gps-C1q is dissociated in a time-dependent manner into the individual chains.
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PMID:Purification and physicochemical properties of C1q from guinea-pig serum. 640

Since the immunosorbent techniques and the cycles of isopycnic and rate zonal velocity ultracentrifugations were shown to be unsuitable for the purification of hepatitis B surface antigen (HBsAg) particles from human sera because HBsAg was still largely contaminated by serum proteins, we applied a drastic dissociating treatment of HBsAg stabilized by adsorption on silica gel which appeared essential to remove extraneous components initially present in the HBsAg particles. Only albumin and sometimes IgG were recovered with the purified antigen. The polypeptide composition of our purified HBsAg preparations was analyzed by SDS-PAGE with subsequent transfer to a nitrocellulose sheet by blotting, incubation with 125I-anti-HBs and exposure to X-ray film. Samples from HBsAg-positive sera containing the hepatitis B virus e antigen (HBeAg) displayed three proteins: P 24.5 and GP 28 as major components and GP 36 as a minor component. Dimers of these polypeptides were also immunologically detected. When a supplementary step of trypsin or pepsin digestion was included in our purification procedure after adsorption to silica and acid dissociation of HBsAg, proteolytic cleavage fragments of HBsAg with mol. wts lower than 10,000 were obtained on SDS-PAGE after reduction. This finding shows that arginine and lysine residues inaccessible to tryptic digestion in the intact HBsAg lipoprotein particle were exposed to enzymatic hydrolysis by our treatment. However, HBsAg kept the antigenic and immunogenic properties of the native antigen. Therefore such a HBsAg preparation appeared as a new candidate for the vaccination against HBV and a useful material for the analysis of the HBs antigenic structure.
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PMID:Immunochemical structure of the hepatitis B surface antigen vaccine--I. Treatment of immobilized HBsAg by dissociation agents with or without enzymatic digestion and identification of polypeptides by protein blotting. 642 72


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