Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel antigen of asexual blood stages of the rodent malaria parasite Plasmodium chabaudi, was detected by means of a modified indirect immunofluorescence assay (IFA), using glutaraldehyde fixed and air dried monolayers of P. chabaudi infected erythrocytes. P. chabaudi hyperimmune sera gave a distinct surface immunofluorescence of erythrocytes infected with early stages of the parasite. Fixation and drying of the erythrocytes was necessary for the antigenic activity to be exposed. The antigens were species specific as P. chabaudi hyperimmune serum only stained P. chabaudi but not P. yoelii or P. falciparum infected erythrocytes. The antigenic activity involved in the IFA was resistant to trypsin, phospholipases and neuraminidase but not to pronase, suggesting that the antigens were polypeptides. The surface immunofluorescence was inhibited by an extract of parasitized erythrocytes, but not by similar extracts of normal erythrocytes. The inhibitory antigens were soluble and heat stable (100 degrees C, 5 min). For identification and characterization of the antigens, antibodies were isolated by acid elution from monolayers of infected erythrocytes and monoclonal antibodies were produced. Probing in immunoblotting of extracts of parasitized erythrocytes separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis with the eluted antibodies, showed that they reacted consistently with a polypeptide of Mr 105 000 (Pch105). The Pch105 antigen shares many characteristics with Pf155, a P. falciparum antigen considered as a candidate for a vaccine against that parasite.
Mol Biochem Parasitol 1986 Jul
PMID:Identification of a Plasmodium chabaudi antigen present in the membrane of ring stage infected erythrocytes. 352 47

Angiotensinogen (Ao), the precursor of the peptide hormone angiotensin, exists in two different forms in plasma, Ao-1 and Ao-2. The completely separated and purified molecules show distinct differences in sodium dodecyl sulfate (SDS)-disc electrophoresis and in analytical isoelectric focusing. Ao-1 is about 3500 Da heavier and contains more acid isoelectric points than Ao-2. In analytical isoelectric focusing Ao-1 displays five bands which overlap with two of the three bands of Ao-2. This difference in charge was eliminated by treatment with neuraminidase for 92 h at 37 degrees C. Thereafter both molecules display an identical-pattern two bands in isoelectric focusing. Treatment of these N-acetylneuraminic acid (NeuNAc)-free forms with renin leads to a shift of these double bands to a more acid pH, indicating heterogeneity within the protein structure. By affinity chromatography on concanavalin A (ConA)-Sepharose, both forms can be separated in three fractions. The analysis of these fractions and of their NeuNAc-free derivatives by SDS-disc electrophoresis, as well as by analytical isoelectric focusing, leads to the conclusion that Ao-1 contains two Asn-linked N-glycan residues with 4-8 mol of NeuNAc, while the smaller form, Ao-2, contains one carbohydrate residue with 2-4 mol of NeuNAc.
Mol Cell Endocrinol 1987 Jun
PMID:Heterogeneity in the carbohydrate structure of rat angiotensinogen. 359 2

The hemagglutinin-neuraminidase (HN) protein of paramyxoviruses is likely in the unusual class of glycoproteins with the amino terminus cytoplasmic and the carboxy terminus lumenal or external to the cell. The properties of the membrane insertion of the HN protein of Newcastle disease virus, a prototype paramyxovirus, were explored in wheat germ extracts containing microsomal membranes. HN protein was inserted into membranes cotranslationally, resulting in a glycosylated protein completely resistant to trypsin and proteinase K digestion. No detectable posttranslation insertion occurred. Insertion required signal recognition particle. Signal recognition particle in the absence of membranes inhibited HN protein synthesis. Comparisons of the trypsin digestion products of the HN protein made in the cell-free system with newly synthesized HN protein from infected cells showed that the cell-free product was in a conformation different from that of the pulse-labeled protein in infected cells. First, trypsin digestion of intact membranes from infected cells reduced the size of the 74,000-dalton HN protein by approximately 1,000 daltons, whereas trypsin digestion of HN protein made in the cell-free system had no effect on the size of the protein. Second, trypsin digestion of Triton X-100-permeabilized membranes isolated from infected cells resulted in a 67,000-dalton trypsin resistant HN protein fragment. A trypsin-resistant core of comparable size was not present in the digestion products of in-vitro-synthesized HN protein. Evidence is presented that the newly synthesized HN protein in infected cels contain intramolecular disulfide bonds not present in the cell-free product.
Mol Cell Biol 1987 Apr
PMID:Translation and membrane insertion of the hemagglutinin-neuraminidase glycoprotein of Newcastle disease virus. 360 Jun 30

Complexes of influenza virus neuraminidase both with antigen-binding (Fab) fragments and with whole monoclonal antibody molecules have been crystallized. Uniformly thin platelet microcrystals suitable for structure analysis by electron diffraction, yielding reflections to approximately 4.3 A resolution, have been grown from one neuraminidase-Fab complex, that of N9 neuraminidase with 32/3 Fab, and thicker crystals of a second neuraminidase-Fab complex (N9 neuraminidase-NC35 Fab) diffract X-rays to approximately 4.0 A resolution. Electron microscope lattice images of microcrystals both of Fab and of immunoglobulin G complexed with neuraminidase have been interpreted in terms of negatively stained images of the respective individual complex protomers. The sites of binding of the antibodies to the antigen are consistent with the notion that single amino acid changes observed in monoclonal variants of neuraminidase occur in binding epitopes for the antibody used for their selection.
J Mol Biol 1986 Jul 20
PMID:Electron and X-ray diffraction studies of influenza neuraminidase complexed with monoclonal antibodies. 379 68

Supernatants of cultures and extracts of Trypanosoma rangeli readily release N-acetyl neuraminic acid from a variety of substrates. The activity in both supernatant and cell extract is precipitated between 30 and 50% ethanol, and between 40 and 70% ammonium sulfate. Fractionation of the culture supernatant by gel exclusion gives a single peak of neuraminidase activity of molecular weight 48 000. The culture supernatant releases sialic acid at different rates from the following substrates:fetuin, sialyllactose and orosomucoid but not from bovine submaxillary mucin and ovomucoid. The enzyme in the culture supernatant is also active against human erythrocytes of all ABO types. The enzyme showed an optimum pH of 5.0 for sialyllactose and erythrocyte substrates. Large amounts of the enzyme are preferentially secreted during growth in vitro.
Mol Biochem Parasitol 1985 Apr
PMID:Neuraminidase activity in Trypanosoma rangeli. 399 Jul 12

The neuraminidase (NA) gene from A/New Jersey (NJ)/8/76 (H1N1, formerly Hsw1 N1) strain isolated in 1976 was cloned into pBR322 and its complete nucleotide sequence was determined. The NJ8 NA gene is 1458 nucleotides long and the sequence predicted the primary structure of the NA molecule comprising of 469 amino acids with a molecular weight of 51,628. Comparison with other NA sequences of the N1 subtype strains which were isolated in 1933-1934 identified the highly variable regions at the amino-terminal stalk region and the carboxy-terminal regions. Potential glycosylation sites encoded by a 15 base-pair unit sequence are arrayed tandemly at the stalk regions. The lengths of stalk regions are highly variable because of segmental deletions in old NA genes. Possible mechanisms for such deletions are discussed.
Mol Biol Med 1983 Nov
PMID:The complete nucleotide sequence of the influenza virus neuraminidase gene of A/NJ/8/76 strain and its evolution by segmental duplication and deletion. 609 54

Monoclonal antibody (McAb) F36/22, raised against a human breast tumor line, identifies an antigen found in the circulation of cancer patients. Antigen was purified from malignant effusions using McAb-affinity chromatography followed by adsorption-desorption from immobilized wheat germ lectin. Electrophoretic analysis demonstrated the isolation of a single high mol. wt glycoprotein exhibiting an isoionic point near pH 4.2 and a density of approx. 1.45 g/ml. Although highly reactive with wheat germ lectin, a negligible or weak interaction was observed with concanavalin A, lentil and peanut agglutinin. The antigen was immune-precipitable, indicating the occurrence of multiple McAb-binding sites, and was resistant to heat and acid treatments. Antigenicity was not perturbed following protease or neuraminidase treatments, but was affected upon exposure to alkaline conditions. Taken together, these data suggest that McAb F36/22 recognizes a high mol. wt component occurring in circulation as a mucin-like glycoprotein.
Mol Immunol 1984 Oct
PMID:Immunoaffinity isolation of ductal carcinoma antigen using monoclonal antibody F36/22. 609 73

Lectins labeled with 125I or conjugated with fluorescein were employed to study the carbohydrates on the surface of different stages of schistosomula of Schistosoma mansoni. Newly transformed schistosomula were shown to bind concanavalin A; the 60 000 and 120 000 dalton agglutinins from Ricinus communis; the fucose-binding protein from Lotus tetragonolobus; wheat germ agglutinin and peanut agglutinin. Soybean agglutinin, Ulex europaeus agglutinin and Dolichos biflorus agglutinin, on the other hand, failed to bind to the schistosomulum surface. The binding of peanut and soybean agglutinin was unaffected by pretreatment of the parasites with neuraminidase. Binding of concanavalin A, the 120 000 dalton agglutinin from Ricinus communis, wheat germ agglutinin and peanut agglutinin to the surface of 5-day schistosomula, recovered from the lungs of mice, was also demonstrated. In each case, however, the level of binding was approximately 70% less than that observed with newly transformed schistosomula and the binding of the fucose-binding protein from L. tetragonolobus practically disappeared. In contrast with newly transformed schistosomula, lung stage schistosomula, pretreated with neuraminidase, displayed a significant increase in the binding of peanut and soybean agglutinin. The results indicate that a significant alteration in the surface carbohydrates of S. mansoni occurs during in vivo maturation of the parasite. This change may contribute to the organism's ability to survive in the vertebrate host.
Mol Biochem Parasitol 1983 Jun
PMID:The exposed carbohydrates of schistosomula of Schistosoma mansoni and their modification during maturation in vivo. 619 37

Four mouse monoclonal antibodies directed against the red cell membrane protein glycophorin A have been isolated and characterized. They are produced by hybridomas derived from SP2/0 myeloma cells and spleen cells from Biozzi mice immunized with a mixture of human erythrocytes from homozygous blood group M and N individuals. These antibodies recognize and bind to purified glycophorin A and to glycophorin on the red cell surface. All are of the IgGl, kappa light chain subclass and bind to determinants presented on the 39 amino acid, trypsin-sensitive, N-terminal peptide of glycophorin A. Three display differential specificities for the two allelic forms of glycophorin A; two are exquisitely specific for the M-form and one preferentially binds the N-form. Treatment of red cells with neuraminidase, which removes N-acetylneuraminic acid from glycophorin A, abolishes the binding of these three antibodies. The binding of the N-specific antibody is also sensitive to modification of the amino-terminal residue of the antigen. The fourth antibody binds equally well to both the M- and N-forms as well as to neuraminidase-treated red cells; thus it recognizes a public, N-acetylneuraminic acid independent glycophorin A determinant.
Mol Immunol 1983 Dec
PMID:Monoclonal antibodies specific for the M- and N-forms of human glycophorin A. 619 36

Bivalent immunoglobulin fragments of IgG, F(ab')2, prepared from normal murine sera were found to be cytotoxic to neuraminidase-treated cells. The fragments were cytotoxic to both allogenic and syngeneic targets (with respect to the source of the sera), suggesting that the antigen bound by the F(ab')2 is not related to the major histocompatibility locus of mice (H-2).
Mol Immunol 1984 Jul
PMID:Immunoglobulin fragments, F(ab')2, that are cytotoxic to enzyme-treated cells. 620 53


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