Glycoproteins present

Neuraminidase inhibitors are the major class of drugs to treat or to prevent the infection with influenza viruses. Currently, two neuraminidase inhibitors are available, zanamivir and oseltamivir, which block the release of new influenza vims from infected host cells and thereby stop the spread of infection. The enzyme neuraminidase is a surface glycoprotein present on all influenza viruses. There are nine influenza neuraminidase sub-types known of which subtypes N1 and N2 appear to be the most important ones. Neuraminidase inhibitors are effective against all neuraminidase subtypes. The activity of the neuraminidase is required for the newly... 

Glucose Hexose Glc UDP-GIc Present during the biosynthesis of N-linked glycoproteins but not usually present in mature glycoproteins. Present in some clotting factors. 

The same ceUs that secrete collagen also secrete fi-bronectin, a large glycoprotein present on cell surfaces, in the extracellular matrix, and in blood (see below). Fi-bronectin binds to aggregating precollagen fibers and alters the kinetics of fiber formation in the pericellular matrix. Associated with fibronectin and procollagen in... 

Specific applications of carbon-13 n.m.r. spectroscopy to the glycophorins, an important family of glycoproteins present in the human erythrocyte membrane, are discussed by K. Dill (Clemson), who demonstrates the value of C-n.m.r. spectra for the structural mapping of glycoproteins. 

It has been estimated that 1-2 per cent of the US population suffer from autoimmune conditions, including rheumatoid arthritis, MS and some forms of diabetes. In many instances, an autoimmune response results from the inappropriate activation of a specific subset of B- and/or T-lymphocytes. The most common immunotherapeutic approach to potentially treat such diseases is to induce depletion of the individual s T- and B-cell populations. This could be achieved by administration of an antibody raised against a surface antigen present on such cells. Initial trials, for example, have shown that injection of an (unconjugated) anti-CD4 antibody (cell surface glycoprotein present on many T-lymphocytes) over 7 days significantly reduced the clinical symptoms of rheumatoid arthritis for several months. 

Avidin, a glycoprotein present in egg white, has a strong affinity for biotin. Biotin is found in the liver. Avidin has four subunits each one with... 

ICAM-1 and -2 are constitutively expressed on endothelial cells ICAM-1 may be further up-regulated by exposure to cytokines. ICAM-3 has recently been described (its identity based on the unique specificity of a monoclonal antibody) and is a 124-kDa glycoprotein present on the surfaces of T cells, monocytes and neutrophils its expression may be up-regulated by stimulants such as mitogens. VCAM-1, which is expressed on the luminal surface of cytokine-exposed endothelial cells, binds T cells via VLA-4. It is also expressed on the surface of some leukaemic cell lines, on rheumatoid synovial cells and on some tumours.On the other hand, ICAM-1 is found on all endothelial surfaces, and its interaction with neutrophil integrins is the major mechanism that results in the stimulation of transendothelial migration. 

This is a 40-kDa transmembrane glycoprotein present on a variety of immune cells, such as neutrophils, B lymphocytes, platelets, eosinophils, monocytes and macrophages however, it is not expressed on NK cells. It binds monomeric IgG with very low affinity but binds well to dimers, tri-mers or aggregated IgG (Ad > 10 7 M). There are about 103 receptors per platelet, 105 per monocyte and 1-2 x 104 per neutrophil. 

The carboxy-terminal region in apolipoprotein (a) closely resembles the protease domain in plasminogen [eight amino acid substitutions, nine amino acid deletions, and one insertion in apo(a) relative to plasminogen, with 94% overall nucleotide sequence identity] (G28). The most important difference is the substitution of arginine by serine in the site responsible for proteolytic activity (position 4308) (G28). As a result, Lp(a) has no protease activity towards substrates for plasmin (J3). Salonen (SI) reported a serine-protease activity of Lp(a) towards fibronectin, a glycoprotein present in connective tissue matrices. 

Cancer antigen MAb to a glycoprotein present on Breast cancer... 

A number of both pre-clinical and clinical studies have used the folate receptor or EBP as a target for immunotherapy of ovarian carcinoma [31,32]. Expression of this tumour-associated antigen by normal tissues is restricted [33]. The carcinoma-associated antigen, EGP-2, also called EpCAM, is a 38-kDA transmembrane glycoprotein, present on the majority of simple, stratified and transitional epithelia [34]. The biological function of EGP-2 has not yet been established. 

A blue, copper-containing glycoprotein present in mammalian blood plasma and containing type 1, type 2, and type 3 copper centers. The type 2 and type 3 copper centers are close together, forming a trinuclear copper cluster. Ceruloplasmin has an important role in the transport and storage of copper ions. Thus, it participates in the metabolism of copper-containing enzymes. 

Lectins have been used for purifying glycoproteins present in cell membranes. The lectin of wheat germ was immobilized on agarose ac-... 

The activities of the purple fluid of the sea hare Aplysia dactylomela, such as toxic, antimicrobial and hemagglutinating properties, have been attributed to a substance of protein nature [332], Proteoglycans and adhesive glycoproteins present in the extracellular matrix of vertebrates, have also been reported in sponges. These molecules are probably involved in the cell adhesion systems of sponges [333], Recently, novel marine proteins have been reported, such as silicatein from sponge biosilica [334], and a metallothionein protein from the marine alga Fuats vesiculosus [335], Metallothioneins have also been isolated from Arctic... 

Nonspecific staining can be caused by Fc receptor glycoproteins present on the cell membrane. This problem is more relevant to frozen sections and smears than to tissues fixed with formaldehyde. The problem can be avoided by using F(ab)2 fragments instead of whole IgG molecules (Boenisch, 2001). Complement-mediated binding may also cause background staining in frozen sections when whole antisera is used however, this problem is not very common. 

Antarctic fishes live in -1.9°C waters, well below the temperature at which their blood is expected to freeze. These fishes are prevented from freezing by antifreeze glycoproteins present in their body. 

HSV-1 vims entry is mediated by multiple glycoproteins present in the envelope and is a rather complex process. Initial adhesion to the cellular membrane is mediated by the interaction of gC and gB with glycosaminoglycan heparan sulfate. Subsequently, gD binds to a specific cellular receptor, either a member of the TNF receptor family [herpes vims entry mediator A (HveA)], immunoglobulin superfamily (HveB, HveC), or 3-O-sulfated heparan sulfate. Then, the vims enters the cell through membrane fusion promoted by the gH/gL complex and gB (117). 

Because age and sex are risk factors of urolithiasis (Fig. 1), radioimmunoassays on males of different ages show that the total urinary testosterone concentrations in stone patients are significantly lower than those in their healthy counterparts (V2). A positive correlation also exists between the total urinary testosterone concentrations and the activity of urokinase (LMW-UK). Steroids such as estradiol, catecholestrogens, and dihydrotestosterone inhibit the urokinase activity in vitro at concentrations higher than 10-5 M (C. H. van Aswegan and D. J. du Plessis, unpublished data). It therefore seems that the activity of urokinase plays a role in the complex process of stone formation by regulating the concentration of glycoproteins present in urine. 

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