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)

Influenza A virus-treated human platelets were lyzed in autologous serum. Lysis required the presence of antibody and occurred predominantly through activation of the classical complement pathway. Binding of the virus followed by its elution at 37 degrees C resulted in a dose-dependent desialation of the cells with a maximal release of 45% of total platelet sialic acid. In contrast, platelets that had been treated with Vibrio cholerae neuraminidase and from which 55% of total sialic acid had been removed were not lyzed in autologous serum and did not bind C3 as shown in binding assays using radiolabeled monoclonal anti-C3 antibody. Thus, the immune-mediated lysis of virus-treated platelets in autologous serum did not involve neoantigens expressed by desialated cells. To assess the effect of viruses on the platelet surface, treated platelets were incubated with galactose oxidase and sodium [3H]borohydride prior to separation and analysis of the labeled glycoproteins by SDS-PAGE. Viral treatment resulted in a desialation of each of the surface glycoproteins. At the same time, a labeled component of Mr 72,000 (nonreduced) and Mr 55,000 (reduced) was observed that was not present when V. cholerae-desialated platelets were examined in the same way. Immunoblotting experiments performed using antiwhole virus and anti-hemagglutinin antibodies demonstrated this component to be viral hemagglutinin. Involvement of membrane-bound hemagglutinin in antibody and in complement-mediated lysis of virus-treated platelets in autologous serum was supported by the increased lytic activity of a postvaccinal serum containing an elevated titer of complement fixing anti-hemagglutinin antibodies. Binding of a viral protein to the platelet surface provides a model for immune thrombocytopenias occurring during acute viral infections at the time of the specific immune response.
 ...
PMID:Membrane-bound hemagglutinin mediates antibody and complement-dependent lysis of influenza virus-treated human platelets in autologous serum. 647 Jan 49

A major glycoconjugate of Leishmania tropica major identified by two monoclonal antibodies was shown to be an externally oriented, amphipathic membrane antigen shed into the culture medium in which the parasites grow. This molecule could be labelled metabolically with [3H]glucose, [3H]galactose, [32P]phosphate and [35S]sulphate. It migrated as a polydisperse band upon electrophoresis in SDS-polyacrylamide gels, spanning the region of the gel corresponding to an apparent mol. wt. of 20 000-67 000 daltons. An apparently identical family of molecules could be labelled on the surface of living promastigotes using galactose oxidase and [3H]-sodium borohydride. This molecule was shown to be released into the supernatant over a period of several hours. Detection of the 3H- or 35S-labelled molecule required several days exposure of autoradiographs, but a novel blotting technique using nitrocellulose coated with monoclonal antibody allowed rapid detection of the molecule in charge shift electrophoresis, Western blotting and dot blotting. The electrophoretic mobility of the glycoconjugate in agarose relative to its mobility in Triton X-100 was increased in the presence of deoxycholate, and decreased in the presence of cetyl trimethyl-ammonium bromide, indicating amphipathic properties consistent with insertion into the lipid bilayer of the membrane. Using the dot-blotting technique the glycoconjugate was detected in all virulent and avirulent clones of LRC-L137 and in two additional isolates of L. tropica major (LRC-L287 and LRC-L251), but not in L. donovani or L. mexicana, consistent with the previously described specificity of the antibodies. However, the general approaches used in this paper showed that L. donovani (LRC-L52) and L. mexicana (LRC-L94) synthesize a similar, but antigenically distinct glycoconjugate.
 ...
PMID:An amphipathic sulphated glycoconjugate of Leishmania: characterization with monoclonal antibodies. 649 30

The outer acrosomal membrane (OAM) of boar spermatozoa was isolated by homogenization and centrifugation through modified colloidal silica. Homogeneity of the isolated membrane fraction (OAM) was revealed by transmission electron microscopy. At least 10 protein components could be discriminated by SDS-PAGE electrophoresis of the OAM, with molecular weights ranging from 340 to 15 kdal. Radiolabelling of the externally disposed carbohydrate side-chains by [3H]borhydride reduction of the isolated membrane, oxidized by use of galactose oxidase, revealed one main galactoprotein with a reduced molecular weight of about 270 kdal. This was identified as the RCA-120 receptor protein by means of lectin-affinity chromatography, high resolution gelfiltration and SDS-PAGE. Screening of the Con A binding properties of the solubilized membrane components partially isolated by affinity chromatography and HPLC was performed by an enzyme-linked-lectin-assay (ELLA). Electrophoretic analysis including a Con A-peroxidase staining procedure allowed the identification of 4 Con A binding proteins of the OAM with molecular weights of 120, 110, 88 and 66 kdal.
 ...
PMID:Characterization of lectin receptors isolated from the outer acrosomal membrane of boar spermatozoa. 661 92

The glycoproteinic nature of the insulin receptor was indicated using two different approaches: 1. [125I] insulin binding to soluble receptors from mouse liver was inhibited by digestion with beta-galactosidase or pretreatment with Ricinus communis I or concanavalin A. An other enzyme (neuraminidase) and lectins (wheat germ agglutinin, Dolichos biflorus) did not affect the binding reaction. These data confirmed that insulin directly interacts with the galactoglycoproteins of liver membranes. 2. The galactose oxidase-sodium boro[3H] hydride technique, previously used for labeling accessible membrane galactoglycoproteins, was again utilized to discern the components that interact with insulin. When liver membranes were equilibrated with 10-7 M insulin prior to labeling, the SDS gel radioactive profiles were specifically modified with two galactoglycoprotein of apparent molecular sizes 195 000 and 145 000, compatible with their participation in the insulin binding interaction. Membrane pretreatment with beta-galactosidase or Sophora japonica lectin reduced the labeling in most peaks, thus supporting the argument for labeling sensitivity. Preincubation of membranes with 10-7 M proinsulin slightly hindered labeling, while pretreatment with 10-7 M glucagon was ineffective, suggesting a specificity of the insulin effect. These data indicate that glycoprotein nature of the insulin receptor for two reasons: alteration of insulin binding after modification of the galactoglycoproteins, and alteration of galactoglycoprotein labeling after insulin binding. Two galactoglycoproteins, with apparent molecular weights 145 000 and 195 000, respectively, were identified and they are suggested to have insulin binding properties.
 ...
PMID:Identification of liver cell membrane galactoglycoproteins involved in the process of insulin binding. 703 Mar 99

A simple method is described that permitted rapid isolation of plasma membranes from mouse N-18 neuroblastoma cells. The purified plasma membranes gave a 10-fold increase in the specific activity of incorporated [3H]fucose over that of the cell homogenate. The specific activities of two other membrane markers, 5'-nucleotidase and alkaline phosphatase, increased 11-fold and 15-fold, respectively. Metabolic labeling with [3H]fucose identified a major fucosyl glycoprotein with apparent molecular weight of 92 000. Three surface labeling methods together with SDS-polyacrylamide gel electrophoresis and fluorography were used to characterize and compare the surface glycoproteins of undifferentiated and differentiated N-18 cells. The galactose oxidase/NaB3H4 method labeled two major galactoproteins (Mr = 52 000, 42 000) in both undifferentiated and differentiated cells. The neuraminidase/galactose oxidase/NaB3H4 method revealed many sialylgalactoproteins. Among them, the 220-kdalton, 150-kdalton and 130-kdalton bands were at least 100% more prominently labeled in the differentiated cells whereas the 76-kdalton and 72-kdalton bands were less prominently labeled in the differentiated cells when compared to their undifferentiated counterparts. The prominently iodinated protein bands in the undifferentiated cells had apparent molecular weights of 130 000, 92 000, 76 000 and 72 000 as compared to 150-, 130-, 92- and 76-kdalton bands in the differentiated cells. The labeling data obtained will enable us to further study the changes of these identified surface glycoproteins, both quantitatively and topologically, during the differentiation of neuroblastoma cells.
 ...
PMID:Identification of exposed surface glycoproteins in undifferentiated and differentiated mouse N-18 neuroblastoma cells. 705 92

Neurons are highly differentiated cells whose various regions must differ in macromolecular composition. This is demonstrated in the present study which shows that specific membrane glycoproteins are routed to particular sites in the cell. When [3H]fucose of [3H]N-acetylgalactosamine are injected into R2, the giant neuron of Aplysia, they are incorporated into relatively few glycoproteins, several of which can be readily identified from cell to cell. Because R2's cell body is so large, its surface membrane can be isolated 94% free of cytosol by manual dissection. The purity of the membrane was assessed by checking the distribution of the enzyme choline acetyltransferase. R2's axon can also be analyzed separately from the cell body. At 24 h after injection, SDS polyacrylamide gel electrophoresis shows that glycoprotein-I (mol. wt. 180,000) is the major labeled component of the external membrane where it is enriched relative to the content of the other cytosolic membranes. In contrast, glycoprotein-V (mol. wt. 90,000) predominates among the membranes of the axon. The disposition of glycoprotein-I in the external membrane was indicated by exposing R2 to low concentrations of pronase in situ 24 h after injection. Labeled glycopeptides were released from R2's surface and gel filtration and high voltage electrophoresis indicated that some of these were derived from glycoprotein-I. Examination of the isolated surface membrane after proteolysis showed a reduced amount of labeled glycoprotein-I. Consistent with these findings, a glycoprotein of similar molecular weight as component-I was labeled when R2 was treated with galactose oxidase and potassium borotritide. These results indicate that the carbohydrate moieties of glycoprotein-I extend from R2's surface.
 ...
PMID:Differences in the distribution of specific glycoproteins among the regions of a single identified neuron. 709 98

The role of the carbohydrate portion of the receptor for IgE in the interaction with IgE was investigated. Membrane carbohydrates of rat basophilic leukemia (RBL) cells and rat mast cells (RMC) were labeled by treating the cells with galactose oxidase followed by [3H]-NaBH4. IgE receptors were separated from detergent solubilized membranes and examined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Pretreatment with neuraminidase markedly increased the incorporation of 3H into both the total membrane extract and into the IgE receptors. SDS-PAGE analysis demonstrated the presence of galactose in all IgE-binding components of 2 RBL cell lines and the presence of sialic acid on the major IgE-binding component. Prior saturation of the cells with IgE did not prevent the carbohydrate labeling of the receptor, although it did block the labeling of its protein part, indicating that carbohydrates are not located in the binding site. Removal of terminal sialic acid residues with neuraminidase increased the affinity of the receptor for IgE without appreciably affecting the number of receptors per cell. In order to more drastically modify the receptor carbohydrates, RBL cells were grown in the presence of Tunicamycin (TN). TN was shown to markedly inhibit the incorporation of [3H]-glucosamine into the receptor. RBL cells grown in the presence of TN expressed fewer receptors at the cell surface, as judged both by ligand binding studies and external labeling procedures. These data cumulatively suggest that the carbohydrate moieties of the receptor are not directly located in the binding site of the IgE receptor; however, the TN studies suggest that receptor carbohydrate may play a role in transport of the receptor to the plasma membrane or in its orientation thereafter.
 ...
PMID:Functional and partial chemical characterization of the carbohydrate moieties of the IgE receptor on rat basophilic leukemia cells and rat mast cells. 720 80

Washed ejaculated chimpanzee spermatozoa and a 100 000 g supernatant of seminal plasma were subjected to radiolabelling by sequential treatment with galactose oxidase and sodium boro[3H]hydride or with sodium metaperiodate and NaB3H4. Sperm surface glycoproteins and seminal plasma glycoproteins radiolabelled by these procedures were compared by SDS-polyacrylamide gel electrophoresis. Spermatozoa labelled by galactose oxidase treatment showed a single labelled macromolecular component of 37 000 whereas spermatozoa labelled by sodium metaperiodate-NaB3H4 treatment showed incorporation into macromolecular components of 37 000 and 25 000 mol. wt. Seminal plasma radiolabelled by galactose oxidase-NaB3H4 treatment contained labelled components of 47 000, 37 000, 19 000 and 12 000 mol. wt, whereas seminal plasma radiolabelled with sodium metaperiodate-NaB3H4 contained macromolecular components of 47 000, 37 000, and 19 000 mol. wt.
 ...
PMID:Characterization of sperm surface and seminal plasma glycoproteins of the chimpanzee. 723 Jan 23

Cell surface proteins and glycoproteins of some human lymphoblastoid- and neoplastic hematopoietic cell lines were labeled by three different techniques: a) lactoperoxidase catalyzed iodination, b) galactose oxidase-tritiated sodium borohydride and c) reductive methylation of free amino groups by tritiated sodium borohydride--a modification of the technique known for the radiolabeling of soluble proteins. Electrophoretic analysis (SDS-PAGE) of labeled surface proteins and glycoproteins resulted in comparable and complementary electrophoretic patterns obtained by these three techniques. Electrophoretic patterns of studied lymphoblastoid cell lines were essentially similar, with an intensively labeled group of glycoproteins (gp44, gp31, gp24). These glycoproteins were markedly reduced on studied neoplastic cell lines. Further differences in several large proteins were observed between lymphoblastoid- and neoplastic cell lines.
 ...
PMID:Cell surface labeling of proteins and glycoproteins of some human cultured lymphoid cells. 725 21

Glycoproteins of human sperm membranes were labelled by a galactose oxidase-tritiated-sodium borohydride technique and detergent solubilized. A glycoprotein-enriched-fraction was obtained by lectin affinity chromatography. Subsequently, antigens in this fraction were isolated from the glycoprotein mixture by indirect immunoprecipitation and analysed in SDS-polyacrylamide gel electrophoresis. With some human sera with sperm agglutinating and immobilizing auto-antibodies at least three polypeptide chains were isolated, one with a molecular weight of about 41,000 and two with molecular weights of about 77,000. Other sera with equally strong agglutination and immobilization did not reveal any peaks in SDS-gel electrophoresis. Absorption studies using sequential indirect immunoprecipitation showed that the former group of sera independently of their mode of agglutination reacted with the same antigen(s).
 ...
PMID:Identification of auto-antigens of the human sperm membrane. 726 78


<< Previous 1 2 3 4 5 Next >>