Search results for "Glycoprotein"
showing 10 items of 852 documents
Complement Receptor Analogous Factors in Human Serum: I. Isolation of a Molecule Inhibitory for Complement Dependent Rosette Formation, its Identific…
1979
Abstract A glycoprotein was isolated from human plasma which partially inhibited C3 carrying erythrocytes from binding to complement receptor cells (CR + C). Based on its physicochemical characteristics and its antigenicity this glycoprotein was identified as aI-antitrypsin (α 1 -AT). The activity of α 1 -AT towards-C3 and its fragments was unaffected by heating but it was destroyed by periodic acid. The isolated carbohydrate moiety of α 1 -AT showed the same effect as the intact molecule. Using F(ab) 2 of IgG-anti-α 1 -AT, α 1 -AT could be demonstrated on Raji cells and human erythrocytes. Treatment of these CR + C with IgG-anti-α 1 -AT resulted in a blockade of their C3 receptor activity.…
Sponge aggregation factor: identification of the specific collagen-binding site by means of a monoclonal antibody.
1988
The aggregation factor (AF) from the sponge Geodia cydonium is known to be a complex proteinaceous particle, composed of a series of different (glyco)proteins (Mr lower than 150,000) around a 90S sunburst-like core structure. One of the low-Mr proteins is the 47-KD cell binding fragment. We describe a new monoclonal antibody (mAb), III1E6, raised against purified AF particles, which recognizes in tissue slices structures present both on the plasma membrane and in a network-like manner in the extracellular space. By applying immunoelectron microscopical, immunoblotting, and immunoaffinity chromatographical techniques, the mAb III1E6 was shown to recognize the core structure of the AF partic…
Cell adhesion molecule in the hexactinellid Aphrocallistes vastus
1984
Abstract The Hexactinellida sponge Aphrocallistes vastus contains a soluble aggregation factor (AF) whose purification has been described in this communication. It is characterized by a S° 20.w value of 37 and a buoyant density of 1.45 g/cm 3 . The AF is a glycoporteinaceous particle composed of three major protein species; no core structure could be visualized. In the presence of Ca 2+ , the AF causes secondary aggregation of single cells. The aggregation process is temperature, pH, and ionic strength independent within a broad range. Evidence is presented indicating that two (or more) AF molecules are required for the establishment of a stable cell: cell interaction. In contrast to the AF…
Posttranslational processing of human alpha 2-HS glycoprotein (human fetuin). Evidence for the production of a phosphorylated single-chain form by he…
1994
alpha 2-HS glycoprotein (alpha 2-HS) is a major protein occurring in human blood and calciferous tissues. Due to extensive sequence identity, alpha 2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native alpha 2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of alpha 2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of alpha 2-HS by a human hepatoma cell line, HepG2. We demon…
C1 Inhibitor-C1¯sComplexes Are Internalized and Degraded by the Low Density Lipoprotein Receptor-related Protein
1997
Like other serpin-enzyme complexes (SECs), proteinase-complexed C1 inhibitor (C1-INH) is rapidly cleared from the circulation and thought to be a neutrophil chemoattractant, suggesting that complex formation causes structural rearrangements exposing a domain which is recognized by specific cell surface receptors. However, the cellular receptor(s) responsible for the catabolism and potential mediation of chemotaxis by C1-INH-protease complexes remained obscure. To determine whether the SEC receptor mediates the binding and potential chemotaxis of C1-INH·C1s, we performed binding assays with HepG2 cells, neutrophils, and monocytes, and the results show that C1-INH·C1s neither bind to these ce…
Butyrate-Induced Growth Arrest of GH3-Cells is not Linked to a Distinct Morphological Phenotype
1983
N-butyric acid is known to be a potent proliferation-inhibitor of a great number of cell types, both normal and neoplastic (1). In many cases growth arrest is accompanied by striking changes in morphology, e.g. formation of cell processes or increased spreading (1). These changes can be traced back to altered glycolipide and glycoprotein patterns of the plasma membrane and to a reorganization of the cytoskeleton (2, 3).
Absence of binding of human salivary glycoprotein to human gingival fibroblast-like cells in vitro.
1996
The aim of this study was to determine whether human high molecular weight salivary glycoprotein binds in vitro to human gingival fibroblast-like cells. Primary monolayer cultures of 2 human gingival fibroblast-like cell lines were incubated with a high molecular weight fraction of salivary glycoprotein which expressed blood group A activity and glycoprotein-cell binding probed using an FITC-conjugated mouse monoclonal antibody to human blood group A antigen. Surface fluorescence of protein-treated cells was found to be no greater than that of untreated or serum-treated control cultures. As significant binding of salivary glycoprotein to gingival fibroblast-like cells does not occur in vitr…
(p-Sulfomethyl)phenylalanine as a mimic of O-sulfatyl-tyrosine in synthetic partial sequences of P-Selectin glycoprotein ligand 1 (PSGL-1)
2007
Abstract Fmoc- l -( p -sulfomethyl)phenylalanine, a bioisosteric mimic of acid-sensitive O -sulfatyl tyrosine, was synthesized from l -tyrosine according to a novel route. Partial sequences of the recognition site of P-Selectin glycoprotein ligand 1 (PSGL-1), which contain (sulfomethyl)phenylalanine were synthesized on solid-phase. By fragment condensation, a sialyl Lewis x peptide conjugate containing a (sulfomethyl)phenylalanine mimic of O -sulfatyl tyrosine was prepared without destruction of the acid-sensitive fucoside bond within the saccharide side chain. Compounds of this type are of interest as sufficiently acid-stable potential inhibitors of P-Selectin in inflammatory processes.
Limited Proteolysis of Human α2-HS Glycoprotein/Fetuin
1996
alpha2-HS glycoprotein is a major protein of human plasma whose function is still obscure. A proteolytically processed form of alpha2-HS glycoprotein lacking a segment of 40 amino acid residues bridging its heavy and light chain portions ("connecting peptide") has been described suggesting that this peptide is released by post-translational processing to fulfill biological role(s) of alpha2-HS glycoprotein. To test this hypothesis we investigated how the connecting peptide is released from the parental molecule by limited proteolysis. We developed monoclonal antibodies to various portions of the connecting peptide and its NH2-terminal flanking region which cross-react with the native alpha2…
Putative multiadhesive protein from the marine spongeGeodia cydonium: Cloning of the cDNA encoding a fibronectin-, an SRCR-, and a complement control…
1998
Sponges (Porifera) representing the simplest metazoan phylum so far have been thought to possess no basal lamina tissue structures. One major extracellular matrix protein that is also a constitutive glycoprotein of the basal lamina is fibronectin. It was the aim of the present study to identify the native protein from the marine sponge Geodia cydonium and to isolate the corresponding cDNA. In crude extracts from this sponge protein(s) of Mr of Ý230 and Ý210 kDa could be visualized by Western blotting using an anti-fibronectin [human] antibody. By PCR cloning from a cDNA library of G. cydonium we isolated a cDNA comprising one element of fibronectin, the type-III (FN3) module. The cDNA (2.3 …