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)

The glycoprotein profile of Bernard-Soulier platelets was examined by labeling washed platelets with periodate 3H-sodium borohydride, a procedure that labels greater than 30 glycoproteins on the membrane surface of normal platelets. Three Bernard-Soulier patients were studied; two were siblings and the third was unrelated. The platelet protein and glycoprotein profiles were evaluated under nonreduced and reduced conditions using 5%-15% exponential SDS-polyacrylamide gel electrophoresis. The two siblings completely lacked glycoprotein Ib (GPIb). The unrelated patient had congruent to 7% of the normal level. This was confirmed by two-dimensional nonreduced-reduced SDS-polyacrylamide gel electrophoresis, a procedure that allows clear separation of the disulfide-linked subunits of GPIb, GPIb alpha (mol wt 145,000), and GPIb beta (mol wt 25,000) from other membrane glycoproteins. On one-dimensional analysis, Bernard-Soulier's syndrome (BSS) platelets also lacked the peripheral membrane glycoprotein, GPV (mol wt 82,000) and a low molecular weight glycoprotein, GPIX, (nonreduced or reduced, mol wt congruent to 22,000). The two-dimensional gel system also revealed the absence of a minor glycoprotein with a molecular weight of congruent to 100,000 (GP 100). Quantitation of these proteins solubilized from electrophoretograms showed that the siblings' parents had congruent to 50% levels of GPIb, GPIX, and GP 100. A monoclonal antibody against glycoprotein Ib, FMC 25, was negative by immunofluorescence against Bernard-Soulier platelets and immuneprecipitated both GP Ib and GPIX from Triton X100 solubilized, labeled platelets. The combined results suggest that the apparent genetic absence of multiple proteins in Bernard-Soulier platelets is due, in part, to the presence in normal platelets of a tight membrane complex between glycoprotein Ib and at least one of the other absent glycoproteins.
 ...
PMID:Additional glycoprotein defects in Bernard-Soulier's syndrome: confirmation of genetic basis by parental analysis. 630 85

A plasma membrane glycoprotein common to embryonic chick myoblasts and adult chicken skeletal muscle satellite cells is the antigen recognized by monoclonal antibody C3/1. Although traces of the same antigen are present on some muscle-derived fibroblasts, the density of antigenic sites on myoblasts and satellite cells is so high that these cell types can be identified in tissues by immunocytochemical techniques. The antigen is exposed on the surfaces of myogenic cells growing in tissue culture and can be solubilized with detergent. This and other criteria establish that the antigen is a plasma membrane protein. The antigen, purified by affinity techniques, consists of a single type of polypeptide chain which migrates as a relatively broad band of apparent molecular weight 38,000 Da in SDS-polyacrylamide gel electrophoresis. It has a very small sedimentation constant, suggesting that the solubilized form is either monomeric or dimeric. The concentration of antigenic sites increases during myogenesis in vitro; but during maturation the antigenic sites are lost from muscle fibers. Electron microscopic autoradiographic study of adult muscle labeled with iodinated monoclonal antibody demonstrated unequivocally that the antigenic sites in adult muscle are concentrated in the satellite cells. Although selective for myoblasts, immature myotubes and satellite cells in the myogenic lineage, the monoclonal antibody also binds at rather high levels to peripheral Schwann cells and teloglia, to some nonneuronal cells in cultures derived from embryonic spinal cord, to some glial elements of adult chicken brain, and to several cell types in the early embryo.
 ...
PMID:Characterization of a plasma membrane glycoprotein common to myoblasts, skeletal muscle satellite cells, and glia. 636 Jul 53

The Triton X-100-insoluble skeleton of baby hamster kidney BHK cells consists of the nucleus, intermediate-size filaments, and actin fibers. By transmission electron microscopy, membrane fragments were found to be associated with these insoluble structures. When radioiodinated or [3H]glucosamine-labeled cells were extracted with 0.5% Triton, most plasma membrane glycoproteins were solubilized except for a glycoprotein with a molecular weight of 85,000 (gp85) that remained associated with the insoluble skeletons. Immunoprecipitation with a specific antiserum indicated that the gp85 is not a proteolytic degradation product of fibronectin, an extracellular matrix glycoprotein insoluble in detergent. A monoclonal antibody of BHK cells specific for gp85 was produced. Immunofluorescence analysis with this monoclonal antibody indicated that gp85 is not associated with the extracellular matrix, but is confined to the cell membrane. Both in fixed and unfixed intact cells, fluorescence was concentrated in dots preferentially aligned in streaks on the cell surface. Gp85 was found to behave as an integral membrane protein interacting with the hydrophobic core of the lipid bilayer since it was extracted from membrane preparations by ionic detergents such as SDS, but not by 0.1 N NaOH (pH 12) in the absence of detergents, a condition known to release peripheral molecules. Association of gp85 with the cell skeleton was unaffected by increasing the Triton concentration up to 5%, but it was affected when actin filaments were dissociated or when a protein-denaturing agent (6 M urea) was used in the presence of Triton, suggesting that protein-protein interactions are involved in the association of gp85 with the cell skeleton. We conclude that gp85 is an integral plasma membrane glycoprotein that might have a role in cell surface-cytoskeleton interaction.
 ...
PMID:A cell surface integral membrane glycoprotein of 85,000 mol wt (gp85) associated with triton X-100-insoluble cell skeleton. 637 25

Cathepsin D was isolated from human brain. A consecutive use of affinity chromatography on hemoglobin-sepharose 4B and column chromatography on hydroxylapatite resulted in a homogeneous enzyme (as was demonstrated by SDS polyacrylamide gel electrophoresis) with a molecular weight of about 48,000, 2800-fold purification and 3.4% yield. Incubation of serum proteins in the presence of purified cathepsin D resulted in a gradual decrease of immunoreactive forms of albumin, orosomucoid, transferrin, and other alpha 1, alpha 2 and beta-globulins. The degradation was revealed by crossed immunoelectrophoresis. Crossed affinity immunoelectrophoresis in the presence of ConA showed specific degradation of serum glycoproteins. Rocket immunoelectrophoresis with monospecific antisera raised against human adult brain glycoprotein D2 revealed a rapid and linear degradation of detergent-solubilized and partially purified human membrane glycoprotein D2 by purified cathepsin D. Incubation of glycoprotein D2 in the presence of cathepsin D (30 min, 37 degrees C) resulted in degradation of 95% of specific protein. An exposure of human brain membrane fragments to cathepsin D resulted in linear degradation of membrane-bound glycoprotein followed by an appearance of a soluble immunoreactive form of protein D2.
 ...
PMID:[Immunochemical study of the degradation of circulating glycoproteins and the neurospecific membrane glycoprotein D2 by cathepsin D of the human brain]. 647 83

Autoantibodies raised in guinea pigs (GP) by hyperimmunization with epididymal sperm recognize antigens present on the plasma membrane of intact sperm and antigens associated with acrosome-reacted sperm. Plasma membrane autoantigens were characterized by SDS-PAGE analysis of immune precipitates from detergent extracts of radiolabeled epididymal sperm. Three major protein bands with approximate molecular weights (MW) of 69,000, 62,000 and 40,000 daltons were exhibited. Galactose oxidase and periodate oxidation followed by tritiation revealed two major plasma membrane glycoprotein autoantigens with MWs of 35,000 and 32,000 daltons and one sialoglycoprotein of 34,000 daltons. Antigenic molecules of similar MW were also detected by autoantisera to guinea pig testicular homogenates. Immune precipitates of radiolabeled detergent extracts of acrosome-reacted sperm analyzed by SDS-PAGE exhibited two major carbohydrate-containing peaks, one with a MW of approximately 42,000 daltons and one of 6,000 daltons. Since the 6,000 dalton peak was immunoprecipitated from the organic phase of both chloroform:methanol 2:1 and n-butanol extracts, the antigen may be a glycolipid. The possible existence of glycolipid autoantigen in GP sperm was further supported by the reaction in a solid phase radioimmunoassay of autoantibodies to GP sperm with glycolipid extracts from GP testis. This study demonstrates the presence of multiple autoantigenic specificities in the sperm-plasma membrane, acrosome-reacted sperm and testis of guinea pigs. It also demonstrates for the first time glycolipid autoantigens in testis and sperm.
 ...
PMID:Immunochemical analysis of guinea pig sperm autoantigens. 703 3

An experimental approach is described that enables the analysis of interactions between exogenous surface ligands and components of the cytoplasm in neutrophil leukocytes. Neutrophils treated with the nonionic detergent Lubrol PX, under controlled conditions, yield intact detergent-insoluble ghosts. Morphological analysis of neutrophil ghosts shows that they retain the original dimensions of the cell and consist almost entirely of a peripheral filamentous network, representing the submembranous cortical web, concentric to nuclear remnants. All intracellular membrane-bounded organelles, plasma membrane, and background cytoplasmic electron density are absent. Biochemical analysis of the ghosts shows that less than 10% of enzyme markers for the soluble and granule fractions remain, and that greater than 90% of total cell phospholipid is removed during detergent extraction. The major proteins remaining in the ghosts comigrate, on polyacrylamide gels in the presence of SDS, with chicken gizzard actin, myosin, filamin, and a 110-kdalton protein. Patches and caps induced on neutrophils with either fluorescein isothiocyanate-concanavalin A or ferritin-concanavalin A retain their original location and morphology on ghosts after lysis, as determined by both fluorescence and electron microscopy. In similar experiments, but using 125I-labeled lectins, 37% of total cell bound concanavalin A (Con A) and 25% succinylated Con A remain attached to the ghosts. A major 125I-labeled membrane glycoprotein (80 kdaltons) is associated with ghosts prepared from intact neutrophils iodinated in the presence of exogenous lactoperoxidase. Further 125I-labeled membrane glycoproteins (217, 170, and 147 kdaltons) become associated with ghosts prepared from iodinated cells treated before lysis with Con A, but not with succinylated Con A. These data taken together suggest that linkages exist in neutrophils between proteins exposed on the outer surface of the plasma membrane and the peripheral filamentous network independent of the presence of lipid bilayer. The implications of these findings for surface motile phenomena will be discussed.
 ...
PMID:Transmembrane linkage between surface glycoproteins and components of the cytoplasm in neutrophil leukocytes. 719 81

The 79 000 mol. wt. measles virion membrane glycoprotein G has been isolated from purified measles virus. Ultracentrifugation of 2% Triton X-100-treated measles virus produced a soluble supernatant fraction containing both G and F, the other external viral membrane protein. Lentil lectin-Sepharose and Sephacryl S-300 column chromatography of this fraction gave a pure preparation of G protein. Sucrose density-gradient centrifugation and SDS-polyacrylamide gel electrophoresis revealed that G was isolated from the virion membrane in the form of a disulphide-linked dimer. Antiserum prepared against purified G reacted only with the G polypeptide of measles virus in a slab gel antibody overlay technique. The antiserum also exhibited haemagglutination inhibition, virus neutralization and haemolysis inhibition activities.
 ...
PMID:Purification and characterization of measles virus haemagglutinin protein G. 729 72

We previously reported that incubating rat adipocytes with [3H]palmitate predominantly labeled an 85-kDa protein. The labeling was more intensive in the presence of insulin and had characteristics consistent with covalent fatty acylation (Jochen et al. 1991. Biochem. Biophys. Res. Commun. 177: 797-801). In order to determine the significance of this finding we purified the 85-kDa protein, determined its N-terminal sequence, and further characterized its interactions with long-chain fatty acids. The [3H]palmitate-labeled 85-kDa protein was purified from rat adipocyte membranes using the following sequence of procedures: i) affinity chromatography with wheat germ agglutinin-agarose, ii) ion exchange chromatography with DEAE-Sepharose, and iii) SDS-polyacrylamide gel electrophoresis. The resulting labeled protein was sequenced through 30 amino acid residues. With the exception of one conserved substitution, the sequence was identical to CD36 (platelet membrane glycoprotein IV). Further characterization of the 85-kDa protein revealed it was heavily N-glycosylated and possessed a cell surface domain. Labeling of the 85-kDa protein with palmitate was compared in control cells, insulin-treated cells, and cells whose energy was depleted with 2,4-dinitrophenol. Insulin and energy depletion increased labeling approximately 3-fold and 12-fold, respectively. Labeling performed in the presence of energy depletion possessed all of the characteristics of covalent protein acylation. In addition, there was a close association between the ability of energy depletion to increase labeling of the 85-kDa protein and its ability to inhibit depletion of [3H]palmitate from the extracellular incubation media. These results suggest that the major substrate for fatty acylation in adipocytes is a cell surface membrane protein related to CD36 and that this acylation has the unusual properties of being independent of intracellular metabolic energy and of occurring on an exofacial epitope of the protein.
 ...
PMID:Purification of the major substrate for palmitoylation in rat adipocytes: N-terminal homology with CD36 and evidence for cell surface acylation. 750 47

P-selectin is a 140 kDa membrane glycoprotein found in secretory granules of platelets and endothelial cells where it is rapidly translocated to the plasma membrane upon cell activation. It then functions as a receptor for various types of leucocytes. Metabolic labelling of resting platelets with 32Pi showed that P-selectin is primarily phosphorylated on serine residues, although some tyrosine phosphorylation was observed as well. However, tyrosine phosphorylation of P-selectin was greatly stimulated by treatment with the permeating phosphatase inhibitor, pervanadate. When P-selectin immunoprecipitates were incubated with [gamma-32P]ATP (in vitro kinase assay), a fraction of P-selectin was phosphorylated on its tyrosine residues by a co-precipitated kinase. P-selectin phosphorylated in vitro co-migrated with 140 kDa surface-labelled 125I-P-selectin during SDS/PAGE under reducing conditions. Under non-reducing conditions, however, phosphorylated P-selectin was disulphide-linked to unknown protein(s) in a 205 kDa complex. In vitro kinase assays of the most abundant platelet tyrosine kinase, pp60c-src, demonstrated the presence of similar 140 and 205 kDa phosphorylated proteins in SDS/PAGE under reducing and non-reducing conditions respectively. Extraction and reprecipitation studies with proteins phosphorylated in vitro indicated that P-selectin and pp60c-src form a 205 kDa 1:1 disulphide-linked complex. In the complex, pp60c-src autophosphorylation is inhibited and P-selectin is phosphorylated on tyrosine residues. As protein disulphides in the cytoplasm of intact cells are extremely rare, our results suggest that P-selectin and pp60c-src, which co-localize in platelet dense granules, may be non-covalently associated and spontaneously form disulphide bridges during lysis. In addition, the observed tyrosine phosphorylation of P-selectin in intact platelets suggests that its function might be regulated by phosphorylation by pp60c-src.
 ...
PMID:Tyrosine phosphorylation of P-selectin in intact platelets and in a disulphide-linked complex with immunoprecipitated pp60c-src. 751 67

The membrane glycoprotein CD36 (GPIV, M(r) 88,000) is found on platelets, monocytes and endothelial cells of the microvasculature. In the present study, anti CD36 antibodies have been identified as occurring with high frequency in patients with thrombotic thrombocytopenic purpura. The presence of anti CD36 antibodies in 15 TTP plasma samples thought to contain them on the basis of an initial screening by protein blots was confirmed by re-screening against a standard of purified CD36, by immunoprecipitation from 125I-labelled control platelets and by dot blots against purified CD36. In a further 28 random samples examined, 23/27 (85%) were CD36-positive by immunoprecipitation, 21/28 (75%) by protein blotting, and 17/28 (60%) by dot blots against purified CD36. On protein blots following SDS-PAGE, immunoprecipitates produced from normal platelets by TTP plasma gave positive reactions with the anti CD36 monoclonal antibody 125I-Mo91. One half of the total TTP samples examined (21/42) caused approximately 70% release in control platelets loaded with 14C-serotonin. Of samples causing release > or = 70%, one-half (8/15) failed to cause release from Naka-negative platelets which constitutively lack CD36 showing that CD36 was the sole target for platelet activation in these TTP samples. These studies demonstrate that antibodies directed against CD36 occur frequently in TTP patients and could cause thrombotic complications and vascular damage by reacting with the parent antigen present in platelets and endothelial cells.
 ...
PMID:Anti-CD36 antibodies in thrombotic thrombocytopenic purpura. 752 43


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