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

Two protein antigens were isolated from excretory-secretory products of Trichinella spiralis by biochemical methods and characterized with respect to their chemical and immunological properties. One antigen, of apparent Mr 43,000, is an abundant secreted protein of infective L1 larvae, while the other, of 45-50 kDa, is present in smaller amounts. Yields, extinction coefficients, isoelectric points, amino acid compositions, and partial N-terminal amino acid sequences for each are reported. Partial amino acid sequences of peptides derived from the 43-kDa protein by cyanogen bromide cleavage have been determined. Treating a reduced-pyridylethylated derivative of the 43-kDa protein with glycopeptidase F (N-glycanase) resulted in formation of a transient product of 37 kDa followed by a stable polypeptide of 32 kDa (by SDS-PAGE), suggesting the presence of two N-linked carbohydrate groups. A similar result was obtained with the 45-50-kDa protein, which gave a transient doublet of 38 and 40 kDa and a final, stable product of 33 kDa, with a minor component of 35 kDa. Two glycosylation sites of the 43-kDa protein and one site of the 45-50-kDa protein can be identified in the amino acid sequences. Polyclonal antibodies prepared against the two proteins cross-reacted extensively, but failed to react with the doubly deglycosylated polypeptides in Western blots. The dominant epitopes present in the reduced-pyridylethylated polypeptides are, therefore, N-linked carbohydrate, although the presence of peptide epitopes in the native proteins cannot be excluded.
Mol Biochem Parasitol 1990 Jun
PMID:Partial characterization of two antigens secreted by L1 larvae of Trichinella spiralis. 239 16

Four monoclonal antibodies that are directed against antigens present in sperm and absent from other worm tissues were characterized. Antibody TR20 is directed against the major sperm proteins, a family of small, abundant, cytoplasmic proteins that have been previously described (Klass, M. R., and D. Hirsh, 1981, Dev. Biol., 84:299-312; Burke, D. J., and S. Ward, 1983, J. Mol. Biol., 171:1-29). Three other antibodies, SP56, SP150, and TR11, are all directed against the same set of minor sperm polypeptides that range in size from 29 to 215 kD. More than eight different sperm polypeptides are antigenic by both immunotransfer and immunoprecipitation assays. The three antibodies are different immunoglobulin subclasses, yet they compete with each other for antigen binding so they are directed against the same antigenic determinant on the multiple sperm proteins. This antigenic determinant is sensitive to any of six different proteases, is insensitive to periodate oxidation or N-glycanase digestion, and is detectable on a polypeptide synthesized in vitro. Therefore, the antigenic determinant resides in the polypeptide chain. However, peptide fragments of the proteins are not antigenic, thus the determinant is likely to be dependent on polypeptide conformation. The antigenic determinant shared by these proteins could represent a common structural feature of importance to the localization or cellular specificity of these proteins.
 ...
PMID:Monoclonal antibodies that recognize a polypeptide antigenic determinant shared by multiple Caenorhabditis elegans sperm-specific proteins. 242 80

During the cellular differentiation of the cultured smooth muscle cells, BC3H1, the Kd and the number of binding sites for [3H]-pyrilamine were decreased transiently from 276 nM to 46.5 nM and from 13.3 x 10(6)/cell to 2 x 10(6) cell, respectively. Concanavalin A (Con-A), wheat germ agglutinin, and lentil lectin inhibited [3H]pyrilamine binding to differentiated BC3H1 cells but not to undifferentiated cells. The [3H]pyrilamine binding activity of digitonin-solubilized membranes from differentiated cells was successively recovered from Con-A agarose affinity chromatography but not from undifferentiated cell membranes. The glycosylation inhibitors tunicamycin and swainsonine inhibited the expression of high affinity pyrilamine binding sites during BC3H1 cell differentiation. The molecular weight of high affinity [3H]pyrilamine binding sites on differentiated cells were approximately 68,000 as analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, which after treatment with N-glycanase was shifted to 40,000, a molecular weight similar to that of low affinity [3H]pyrilamine binding sites on undifferentiated cells. These data suggest that one element contributing to H1-receptor heterogeneity is receptor-N-glycosylation.
Mol Pharmacol 1989 Mar
PMID:Receptor glycosylation regulates the affinity of histamine H1 receptors during smooth muscle cell differentiation. 249 28

The major component immunoprecipitated from human red cell membranes by murine monoclonal antibodies (BS46 and BS56) against the LW blood group antigens is a 42,000 mol. wt glycoprotein. Upon digestion by an N-glycanase the LW component migrated as a 25,000 mol. wt component on SDS gels, whereas treatment by an O-glycanase led only to a small size reduction (2000). These data suggest that the LW glycoprotein might carry approximately eight to nine N-linked sugar chains and only a few (one or two) O-linked oligosaccharide chains. A minor component of 31,000 mol. wt was also identified in the LW immunoprecipitate. Preliminary analyses by two-dimensional peptide mapping indicate that the 31,000 mol. wt polypeptide is identical to authentic Rh proteins, therefore raising the possibility that the Rh and LW antigens are associated in the membrane as a functional complex called Rh cluster. Since the N-deglycosylated form of the LW and RhD proteins have different sizes (25,000 vs 31,000-32,000 respectively) and since their externally 125I-labelled domains have different two-dimensional peptide maps, it is concluded that LW is probably not a simple glycosylated form of the Rh proteins.
Mol Immunol 1989 Nov
PMID:Properties of the blood group LW glycoprotein and preliminary comparison with Rh proteins. 251 51

The effect of enzymatic deglycosylation of human complement component C9 on its hemolytic activity was investigated. Treatment of native C9 (Mr 71,000) with glyocpeptidase F (PNGase F) results in a stepwise decrease of the mol. wt. The formation of an Mr 67,000 peptide which is further converted to Mr 63,000 suggests that there are two N-linked carbohydrate chains per C9 polypeptide. Removal of approximately 88% of the N-linked oligosaccharides results in 80% reduction of the hemolytic activity (CH50). The completely N-deglycosylated Mr 63,000 peptide contains a remaining amount of 25% of the total carbohydrates of native C9. These glycans are assumed to be O-linked and predominantly attached to the C9a part of C9. The electrophoretic mobility of C9 is not affected by endoglycosidase F or H treatments revealing that the two N-linked glycans are of the tri- or tetra-antennary complex type. Cleavage of terminal sialic acids from native C9 by neuraminidase results in an Mr 67,000 product with nearly unaltered hemolytic activity. In contrast to other glycoproteins in which deglycosylation remained without major effects on their functional activity, our findings suggest that the N-linked carbohydrates are required for full expression of hemolytic activity of C9.
Mol Immunol 1989 Dec
PMID:N-deglycosylation of human complement component C9 reduces its hemolytic activity. 263 47

To examine the function of the carbohydrate chains of cobra venom factor (CVF), the molecule was enzymatically deglycosylated under non-denaturing conditions with N-glycanase (peptide-N4-(N-acetyl-beta-glucosaminyl) asparagine amidase). The deglycosylation of CVF chains seems to proceed independently of each other, leading to partially deglycosylated intermediates. Complete deglycosylation of CVF was found to abolish the activity of CVF. The deglycosylated molecule is unable to activate the alternative pathway of complement. Deglycosylated CVF no longer consumes the serum complement activity, it does not induce C3 activation in serum, nor does it induce complement-mediated hemolysis. These results indicate that the carbohydrate moieties of CVF are essential for its role in complement activation.
Mol Immunol 1989 Jun
PMID:The oligosaccharide chains of cobra venom factor are required for complement activation. 277 Jul 49

NIH 3T3 cells were transfected with cDNA corresponding to human kidney prepro-epidermal growth factor (preproEGF) under control of the inducible mouse metallothionein promoter. The synthesis of recombinant human EGF precursor by these cells has provided us with a model system for analysis of the structure and activity of this precursor. In transfected cells, the precursor was present as an intrinsic 170-kilodalton membrane protein as well as a soluble protein in the extracellular medium; both forms were N glycosylated. Glycosylation of the EGF precursor was determined by (i) the direct incorporation of [3H]mannose and [3H]glucosamine, (ii) metabolic labeling in the presence or absence of glycosylation inhibitors, (iii) enzymatic cleavage of the precursor by N-glycanase or endoglycosidase II, and (iv) lectin chromatography. Recombinant human preproEGF was purified by affinity chromatography, using wheat germ lectin and antibodies to human EGF. The intact precursor was biologically active. Purified preparations of preproEGF (i) competed with 125I-labeled EGF for binding to the EGF receptor in intact fibroblast cells, (ii) activated the intrinsic tyrosine kinase activity of the EGF receptor in membrane preparations, and (iii) sustained the growth of a mouse keratinocyte cell line that is dependent on EGF for growth. These results suggest that proteolytic processing of the precursor may not be essential for its biological function.
Mol Cell Biol 1989 Jul
PMID:Recombinant human epidermal growth factor precursor is a glycosylated membrane protein with biological activity. 278 34

The high affinity Fc receptor (FcRI) of a human monocytic cell line, U937, was further characterized using a previously described murine monoclonal antibody, FcRmAb32. This antibody immunoprecipitated a 70 K cell surface glycoprotein. A solid phase ligand binding assay and a solid phase immunoprecipitation assay were combined to confirm that the 70 K cell surface glycoprotein immunoprecipitated by FcRmAb32 is an IgG binding protein. N-glycanase digestion shows that at least 20% of the relative mobility of the 70 K FcRI glycoprotein is due to N-linked carbohydrate. FcRmAb32 immunoprecipitated a 70 K glycoprotein from biosynthetically labelled U937 cells that co-migrated with the surface iodinated glycoprotein on 2-dimensional gel electrophoresis. A 50 K protein, that is biosynthetically labelled but not accessible to surface iodination, which, bound to control antibodies was also present in FcRmAb32 immunoprecipitates. FcRmAb32 only bound the mature fully glycosylated form of FcRI. The 70 K FcRI was not phosphorylated constitutively nor when U937 cells were stimulated by PMA.
Mol Immunol 1988 Mar
PMID:Characterization of the human monocyte high affinity Fc receptor (hu FcRI). 296 28

The ligand-binding subunit of the porcine striatal dopamine D2 receptor was identified by photoaffinity labeling with [125I]N-azidophenethylspiperone ([125I]NAPS). Upon photolysis, [125I]NAPS covalently incorporated into a broad band of apparent Mr congruent 140,000 with an appropriate pharmacological profile for D2 receptors as assessed by autoradiography after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Smaller subunits of apparent Mr congruent 94,000 and 34,000 were specifically labeled by [125I]NAPS with an appropriate D2 receptor profile and were similar to the major ligand-binding subunits of photoaffinity-labeled canine striatal D2 receptors. Photoaffinity labeling in the absence or presence of multiple protease inhibitors did not alter the migration pattern of the Mr congruent to 140,000/94,000 subunits upon denaturing electrophoresis in either the absence or presence of thiol-reducing/alkylating reagents. In order to investigate the possible basis for the existence of these high molecular weight forms of the D2 receptor, we assessed the carbohydrate nature of photolabeled D2 ligand-binding subunits by the use of lectin affinity chromatography and specific exo- and endoglycosidase treatments. Both photoaffinity-labeled D2 receptor proteins from porcine striatum (Mr congruent to 140,000 and 94,000) were glycoproteins as indexed by their absorption and specific elution from wheat germ agglutinin lectin resins. The exoglycosidase neuraminidase altered the electrophoretic mobility of both the Mr congruent to 140,000 and 94,000 labeled subunits to a single band of apparent Mr congruent to 51,000. Prior removal of sialic acid residues did not alter the reversible binding characteristics of [3H]spiperone to D2 receptors. Complete removal of receptor-associated N-linked carbohydrate by the endoglycosidase glycopeptidase F (peptide-N4[N-acetyl-beta-glucosaminyl]asparagine amidase) produced a further increase in the mobility of the Mr congruent to 51,000 subunit to apparent Mr congruent to 44,000. The porcine Mr congruent to 34,000 photolabeled peptide is an N-linked glycoprotein as assessed by lectin affinity chromatography and susceptibility to digestion by glycopeptidase F to a peptide of apparent Mr congruent to 23,000.(ABSTRACT TRUNCATED AT 400 WORDS)
Mol Pharmacol 1988 Aug
PMID:Dopamine D2 receptor binding subunits of Mr congruent to 140,000 and 94,000 in brain: deglycosylation yields a common unit of Mr congruent to 44,000. 297 May 86

Analyses of cDNA clones coding for simian type 1 transforming growth factor beta (TGF-beta 1) suggest that there are three potential sites for N-linked glycosylation located in the amino terminus of the precursor region. Analysis of [3H]glucosamine-labeled serum-free supernatants from a line of Chinese hamster ovary cells which secrete high levels of recombinant TGF-beta 1 indicate that the TGF-beta 1 precursor, but not the mature form, is glycosylated. Digestion with neuraminidase resulted in a shift in migration of the two TGF-beta 1 precursor bands, which suggests that they contain sialic acid residues. Endoglycosidase H had no noticeable effect. Treatment with N-glycanase produced two faster-migrating sharp bands, the largest of which had a molecular weight of 39 kilodaltons. TGF-beta 1-specific transcripts produced by SP6 polymerase programmed the synthesis of a 42-kilodalton polypeptide which, we suggest, is the unmodified protein backbone of the precursor. Labeling with 32Pi showed that the TGF-beta 1 precursor was phosphorylated in the amino portion of the molecule.
Mol Cell Biol 1988 May
PMID:Recombinant type 1 transforming growth factor beta precursor produced in Chinese hamster ovary cells is glycosylated and phosphorylated. 316 41


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