Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiotensin-converting enzyme has been solubilized from a particulate fraction of rabbit lung and purified to apparent homogeneity in 11% yield by a procedure including fractionation with DEAE-cellulose and calcium phosphate gel, elution from Sephadex G-200, and lectin affinity chromatography. The molecular weight estimated by equilibrium sedimentation was approximately 129,000, either in the absence or presence of 6 M guanidine hydrochloride. A slightly higher value of 140,000 determined for the reduced, denatured protein by gel electrophoresis in the presence of sodium dodecyl sulfate and a much higher figure derived from gel filtration are probably due to the glycoprotein nature of the enzyme. Its oligosaccharide content accounted for 26% of the weight calculated from its amino acid and carbohydrate composition. The estimated content of sugar residues per mole was: galactose, 57; N-acetylglucosamine, 53; mannose, 43; N-acetylneuraminic acid, 19; and fucose, 4. Threonine and alanine were identified, respectively, as NH2-terminal and COOH-terminal residues by the dansylation procedure and by digestion with carboxypeptidase A. The enzyme was found to contain approximately 1 g atom of zinc per mol. Km values for hydrolysis of hippurylhistidylleucine and angiotensin I were 2.3 and 0.07 mM, and the corresponding turnover numbers were 15,430 and 792 mol/min/mol at 37 degrees. Bradykinin was also a substrate, and release of its COOH-terminal dipeptide, Phe-Arg, was catalyzed at a comparable rate to that of His-Leu from the COOH terminus of angiotensin I. Enzyme activity required the presence of chloride ions and was inhibited by EDTA and by low concentrations of Bothrops bradykinin-potentiating peptides. In addition, hydrolysis of hippurylhistidylleucine was inhibited competitively by other defined peptides, including di- and tripeptides, which were not substrates.
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PMID:Pulmonary angiotensin-converting enzyme. Structural and catalytic properties. 16 57

Determination of the amino acid sequence of the immunogenic polypeptides of hepatitis B surface antigen may not only permit molecular localization of the distinct determinants a, d, and y but may also lead to the synthesis of a hapten useful in prophylactic immunization against hepatitis B virus infection. For this purpose, purified monotypic hepatitis B surface antigen of adw subtype was resolved into equal amounts of two major polypeptides (22,000 and 28,000 daltons) and up to six other minor polypeptides by polyacrylamide gel electrophoresis. With the periodate staining reaction, only the 28,000-dalton polypeptide stained as a glycoprotein. Guinea pigs immunized with the 22,000-dalton polypeptide produced potent antisera against determinants a and d, but the 28,000-dalton glycoprotein did not induce a response. Both polypeptides isolated by preparative polyacrylamide gel electrophoresis showed amino acid composition identical with that of the intact antigen. For both polypeptides, hydrazinolysis gave Ile as the carboxyterminus, and carboxypeptidase A digestion gave the same terminal sequence, Val-Tyr-Ile. Both peptides also yielded an identical sequence of amino acids in nine steps of Edman degradation--Met-Glu-Asn-Ile-Thr-Ser(Cys)-Gly-Phe-Leu. Our data suggest that hepatitis B surface antigen contains a single major immunogenic 22,000-dalton polypeptide component, part of which is modified by the addition of carbohydrate to give rise to the glycopeptide of apparent molecular weight 28,000.
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PMID:Partial amino acid sequence of two major component polypeptides of hepatitis B surface antigen. 26 93

The bovine exocrine pancreatic cell produces a variety of enzymes and proenzymes for export. Biochemical studies by Greene L.J., C.H. Hirs, and G.E. Palade (J. Biol. Chem. 1963. 238:2054) have shown that the mass proportions of several of these proteins in resting pancreatic juice and zymogen granule fractions are identical. In this study we have used immunocytochemical techniques at the electron microscope level to determine whether regional differences exist in the bovine gland with regard to production of individual secretory proteins and whether specialization of product handling occurs at the subcellular level. The technique used is a modification of one previously reported (McLean, J.D., and S.J. Singer. 1970. Proc. Natl. Acad. Sci U.S.A. 69:1771) in which immunocytochemical reagents are applied to thin sections of bovine serum albumin-imbedded tissue and zymogen granule fractions. A double antibody technique was used in which the first step consisted of rabbit F(ab')2 antibovine secretory protein and the detection step consisted of sheep (F(ab')2 antirabbit F(ab')2 conjugated to ferritin. The results showed that all exocrine cells in the gland, and all zymogen granules and Golgi cisternae in each cell, were qualitatively alike with regard to their content of secretory proteins examined (trypsinogen, chymotrypsinogen A, carboxypeptidase A, RNase, and DNase). The data suggest that these secretory proteins are transported through the cisternae of the Golgi complex where they are intermixed before copackaging in zymogen granules; passage through the Golgi complex is apparently obligatory for these (and likely all) secretory proteins, and is independent of extent of glycosylation, e.g., trypsinogen, a nonglycoprotein vs. DNase, a glycoprotein.
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PMID:Immunocytochemical localization of secretory proteins in bovine pancreatic exocrine cells. 31

An acidic proteolytic enzyme which digests host haemoglobin can be isolated and purified from schistosomes. This small glycoprotein is an allergen which sensitizes the host, as shown by immediate hypersensitivity reactions. These are specific for either Schistosoma haematobium or S. mansoni and can be demonstrated by mast cell degranulation in mice or by intradermal skin tests in monkeys. Although high levels of total IgE may be found in acute and chronic schistosomiasis, there was no evident relationship between the worm burden in monkeys and immediate hypersensitivity reactions to either purified enzyme or crude schistosomal extracts. It is suggested that an in vivo correlation between worm burden and manifestations of the allergic response may be perturbed by high titres of non-specific IgE or other homocytotropic antibodies, thus accounting for false negative skin test reactions. Alternatively, a return to low or subnormal IgE levels may allow the restoration of the allergic response, giving rise to false positive reactions. Purified schistosomal antigens offer certain advantages over crude skin test preparations in terms of uniformity of antigen content, dosage and specificity. In addition, the enzyme may represent a species-specific tool for new immunochemical analyses of schistosomiasis.
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PMID:Species specificity of the immediate hypersensitivity to schistosomal proteolytic enzyme. 39 32

The C5a molecule is one of two spasmogenic fragments (i.e. C3a and C5a) released from serum components C3 and C5 during complement activation. These fragments are called anaphylatoxins because their ability to stimulate mast cell histamine release, smooth muscle contraction, and increased vascular permeability may lead to a fatal reaction resembling anaphylactic shock in experimental animals. In addition, the C5a molecule, which is a glycoprotein, is perhaps the most potent of all humoral chemoattractants for polymorphonuclear leukocytes. Most of the structural analyses in this study were performed on the desArg 74 form of human C5a (C5adesArg). C5adesArg represents a natural form of C5a that is recovered from activated serum when no inhibitors are added to block the action of serum carboxypeptidase. The complete primary structure of the human C5a polypeptide portion is reported here. A partial characterization of intact human C5a has been previously reported (Fernandez, H. N., and Hugli, T. E. (1976) J. Immunol. 117, 1688--1694). The polypeptide portion of C5a contains 74 amino acids, accounting for a molecular weight of 8,200 while the carbohydrate portion accounts for approximately 3,000. The carbohydrate portion of C5a exists as a single complex oligosaccharide unit attached to an asparagine at position 64. An unusual feature of the C5a molecule is its large content of half-cystine, which accounts for more than 9% of its total residues. Two repeating Cys sequences occur in the linear structure and 6 of the 7 half-cystines in C5a are located at nearly identical positions to those in the human C3a molecule. In fact, sequence similarities between C3a and C5a indicate their common genetic ancestry. The role of C5a and C5adesArg as chemotactic factors prompted comparisons of their structural features with those of the chemotactically active formyl-Met peptides (Schiffman E., Corcoran, B. A., and Wahl, S. M. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 1059--1062). Removal of the COOH-terminal arginyl residue from C5a reduces chemotactic activity; therefore, the terminal portion of this molecule appears to play an active role in stimulating leukocyte migration. Hence the COOH-terminal sequence of C5a was examined for structural similarities to that of the formyl-Met peptides. Since methionine assumes a special functional importance in the formyl-Met peptides, attention is focused on the single methionyl residue in C5a. This methionyl residue, located near the COOH terminus of the molecule, may play an active role in the functional expression of C5a as a chemotactic factor. Although human and pig C3a show a close structural and functional relationship to C5a they lack the ability to excite leukotaxis, and this difference may correlate with the absence of a methionyl residue near the COOH terminus of C3a.
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PMID:Primary structural analysis of the polypeptide portion of human C5a anaphylatoxin. Polypeptide sequence determination and assignment of the oligosaccharide attachment site in C5a. 69 Jan 34

Highly purified glycoprotein from the intimal region of porcine aorta was isolated with minor modifications of the procedure described previously. The molecular weight of the glycoprotein as determined by sedimentation equilibrium method either in presence of 0.1 M NaCl or 6 M guanidine-HCl containing beta-mercaptoethanol was 72 000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the native glycoprotein and its S-carboxyamidomethyl derivative at different acrylamide concentrations showed no difference in the molecular weight indicating the absence of subunits. Attempts to determine the identity of the amino-terminal acid by a dansylation technique indicated that the amino group is not free. The carboxy-terminal amino acid was found to be serine after treatment of the glycoprotein with carboxypeptidase A. The glycoprotein did not contain an alkali-labile (O-glycosidic) carbohydrate-protein linkage as tested by the beta-elimination reaction. The release of monosaccharides from the glycoprotein as a function of time was studied employing mild acid hydrolysis (0.5 M HCl, 80 degrees C) and also by the use of neuraminidase, alpha-D-and beta-D-glucosidases and beta-D-N-acetylglucosaminidase. From the observations of the release of monosaccharides and analogy with standard features determined by other investigators on soluble aortic glycoproteins, a prediction has been made as to the general features of the carbohydrate moiety of the glycoprotein.
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PMID:Further studies on a highly purified glycoprotein from the intimal region of procine aorta. 95 56

We have isolated and characterized subpopulations of the rat mucosal mast cell line, RBL-2H3, carrying either high or low density of a glycoprotein, recently established as mast cell function-associated antigen (MAFA, Ortega et al., 1991), on their surface. These populations were investigated in order to better define the involvement of the MAFA in coupling the immunological stimulation of mast cells to mediator release. The MAFA density on the cell surface of the deficient subpopulation was less than or equal to 10-20% that of the parental population and this phenotype was found to be stably maintained for several months. In contrast, the MAFA-enriched cells had maximally twice the number of copies per cell surface than that of the parental population and this phenotype was less stable. Significantly, low copy number of MAFA on the cell's surface was accompanied by a markedly different secretory response, i.e. (i) a considerable decrease in the secretory response to the Fc epsilon RI-mediated stimulus (ii) a marked enhancement of the ionomycin induced secretion. In order to gain insight into the causes for this decrease in cellular response to the Fc epsilon RI-mediated stimulus, we measured the amplitudes of several biochemical processes which are assigned to the stimulus-secretion coupling cascade. The Fc epsilon RI-mediated uptake of 45Ca2+ by the MAFA-deficient cells was considerably lower than that of the parental and MAFA-enriched cells. Similarly, these cell's Fc epsilon RI-induced rise in [Ca2+]i (both the initial transient as well as the sustained elevation), was markedly lower than that of the parental line and the MAFA-enriched cells. Moreover, the low initial transient rise in [Ca2+]i was found to be correlated with the decrease in Fc epsilon RI-mediated IP3 levels. We therefore examined the cell's content of the phosphatidyl-inositides hydrolyzing enzyme, phospholipase C gamma 1. This was found to be similar in the parental line and in its derived subpopulations. However, PLC gamma 1 activation, as measured by the time course of phosphorylation of its tyrosines, showed a marked difference: while PLC gamma 1 tyrosine phosphorylation, in the parental cells, was only transient (detected already 1 min after antigen addition and declined afterwards to basal levels at ca. 10 min), in the MAFA-deficient cells, tyrosine phosphorylated PLC gamma 1 was also observed 1 min after antigen addition, yet showed no decrease with time in its phosphorylation intensity for up to 30 min.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Variants of the mucosal mast cell line (RBL-2H3) deficient in a functional membrane glycoprotein. 145 97

gp49 is a Mr 49,000 glycoprotein expressed on the surface of mouse bone marrow-derived mast cells, which are progenitors for the major in vivo mast cell subclasses, typified by intestinal mucosal mast cells and serosal mast cells. The amino-terminal amino acid sequence of gp49 was determined after isolation of the solubilized membrane protein by affinity chromatography with the B23.1 anti-gp49 monoclonal antibody. Redundant oligonucleotides were used to isolate a full-length 1.3-kilobase cDNA from a mouse mast cell library. The predicted amino acid sequence contains a signal peptide of 23 residues, an extracellular domain of 215 residues with three potential sites of N-linked glycosylation, a transmembrane domain of 23 residues, and a cytoplasmic tail of 42 residues. Hybridization of the gp49 cDNA was limited to mRNA extracted from those cell types that also bound the B23.1 monoclonal antibody as assessed by cytofluorographic analyses. The predicted extracellular domain of gp49 contains two regions of 48 and 51 amino acids, each flanked by cysteine residues. Both regions meet criteria for being C2-type domains of the immunoglobulin superfamily based upon the alignment of consensus amino acids and their predicted secondary structure organization. Thus, gp49, a membrane glycoprotein preferentially expressed by the progenitor mast cell population, is a new member of the immunoglobulin superfamily.
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PMID:Molecular cloning of gp49, a cell-surface antigen that is preferentially expressed by mouse mast cell progenitors and is a new member of the immunoglobulin superfamily. 171 1

We have recently described a monoclonal antibody, mAb G63, which identifies a novel membrane component of mast cells. This antigen is a glycoprotein with an apparent molecular mass of 28-40 kd, and is present on the surface of rat mucosal and serosal mast cells. Its density on cells of the mucosal mast cell line RBL-2H3 is 1 - 2 x 10(4) copies per cell. Crosslinking of this membrane protein by the intact mAb G63 results in a pronounced inhibition of the Fc epsilon RI-mediated secretion of RBL-2H3 cells. Here we show that crosslinking this novel membrane component inhibits biochemical processes initiated by Fc epsilon RI aggregation, such as the hydrolysis of phosphatidylinositides, the influx of Ca2+ ions, and the synthesis and release of de novo formed inflammatory mediators. Furthermore, by fluorescence microscopy, we show that crosslinking of Fc epsilon RI-IgE complexes by multivalent antigen results in redistribution of the membrane component recognized by G63, leading to its co-localization with the aggregated Fc epsilon RI. This localization is inhibited by NaN3, but not by colchicine or cytochalasin D. Fc epsilon RI crosslinking also promotes internalization of this novel membrane component. Taken together these data suggest that the mast cell membrane component recognized by mAb G63 is involved in the Fc epsilon RI-mediated stimulation of these cells, and thus can be considered a mast cell function-associated antigen (MAFA).
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PMID:Possible interactions between the Fc epsilon receptor and a novel mast cell function-associated antigen. 183 52

The proliferation of mucosal mast cells (MMC) depends on the presence of interleukin 3 (IL 3) and can be further enhanced by interleukin 4 (IL 4). The supernatant of a TH2 cell clone (ST2/K.9) stimulated by concanavalin A was found to contain a factor, provisionally termed mast cell costimulatory activity (MCA), that substantially enhances the proliferation of MMC promoted by a combination of IL 3 and IL 4. In comparison to other lymphokines MCA is rather resistant to tryptic digestion but is very sensitive to pH values lower than 6.0 and to organic solvents. Chromatographic fractionation of MCA revealed that activity is associated with protein(s) or glycoprotein(s) of 35 to 40 kDa. Partially purified MCA that was functionally free of other T-cell-derived lymphokines did not stimulate mast cell proliferation in the absence of a combination of IL 3 and IL 4. In addition, MCA did not affect the proliferation of mast cells when employed together with either IL 3 or IL 4 alone. Control experiments demonstrated that MCA is identical to neither the T-cell-derived lymphokines IL 2 to IL 6, IL 9, interferon gamma, tumor necrosis factor alpha or beta, or granulocyte-macrophage colony-stimulating factor (CSF), nor to IL 7, granulocyte CSF, macrophage CSF, erythropoietin, leukemia inhibitory factor, or epidermal growth factor (EGF). Finally, experiments using a panel of PPD-reactive TH1- and TH2-like cell lines revealed that MCA is preferentially produced by TH2 cells. These data, especially the relative resistance of MCA to trypsin and the high sensitivity to low pH values and organic solvents, indicate that MCA is distinct from known T-cell-derived lymphokines.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of a T-cell-derived mast cell costimulatory activity (MCA) that acts synergistically with interleukin 3 and interleukin 4 on the growth of murine mast cells. 210 34


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