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)

L4, the affinity of hemoglobin for the 4th CO molecule, has been determined for human adult hemoglobin (HbA) as a function of pH and the presence of organic phosphates by measuring the kinetic parameters for the reaction. l'4, the rate of combination of CO with the triliganded molecule, was measured by flash photolysis while l4, the rate of CO dissociation for the ligand-saturated molecule, was measured by ligand replacement. L4 is pH-dependent and affected by 2,3-diphosphoglycerate. Additionally, this pH dependence of the high affinity state is largely eliminated by carboxypeptidase A digestion. L4 for human fetal hemoglobin (HbF) in phosphate buffers was also determined and found to be pH-dependent. These results cannot be reconciled within the framework of the two-state allosteric model. Additional structures in the conformational equilibrium due to either intermediates in the T to R transition or two or more R states must exist.
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PMID:Kinetic studies on the binding affinity of human hemoglobin for the 4th carbon monoxide molecule, L4. 1 Mar 2

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

A comparative study was carried out on the effects of a soluble derivative of baicalein, disodium baicalein 6-phosphate (BPS) and disodium cromoglycate (DSCG) on the immediate type allergic reactions. BPS not only inhibited reaginic antibody-mediated reactions including antigen-induced mediator release from monkey lung, homologous PCA in rats, and reaginic antibody-mediated degranulation of mast cell, but also non-reaginic antibody-mediated reactions such as mediator release from guinea pig lung sensitized with ovalbumin and that from human lung caused by anti-IgE. The agent, however, did not affect the mediator release from lung of rats sensitized with dinitrophynylated ascaris extract plus Bordetella pertussis. On the other hand, DSCG showed characteristic properties as an inhibitor of reaginic antibody-mediated reaction. It is thus assumed that the functional site of reaginic antibody is well fixed with DSCG at a definite distance between the two-chromone-nuclei while that of IgG is readily fixed with the two molecules of baicalein or BPS.
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PMID:A comparative study of the anti-allergic effects of disodium baicalein 6-phosphate (BPS) and disodium cromoglycate (DSCG). 40 19

Dipeptidyl aminopeptidase II (DAP II) was demonstrated cytochemically in rat peritoneal mast cells. The bright red reaction product in smears of peritoneal wash fluid tended to be localized in one to eight granules in the perinuclear region of the cell. This finding was confirmed at the electron microscopic level, where a small proportion of the granules, most often located near the nucleus, revealed electron opacity indicative of DAP II. Focal areas in the nuclear envelope densified by DAP II reaction product resembled reactive foci observed previously in the nuclear envelope of peritoneal macrophages. In mast cells exposed 1 to 2 hours to phosphate-buffered saline containing horseradish-peroxidase--coated colloidal gold, the spherules of gold were internalized and transported exclusively to the DAP II-reactive granules. Their content of endocytosed gold thus identified DAP II-reactive granules as secondary lysosomes of heterophagic nature. Mast cells induced to release their granules by stimulation with the divalent cation ionophore A23187 retained exclusively those granules possessing DAP II or acid phosphatase reactivity. This selective granule retention after ionophore exposure further differentiated granules with DAP II reactivity from the other non-reactive mast cell granules, presumably indicating a difference between the limiting membrane of granules that are converted to secondary lysosomes and the membrane of those that are not altered and persist as primary lysosomes. Demonstration of the DAP II reactivity in a minority of mast cell granules and of the heterophagic nature of these granules provides evidence that tissue mast cells in vivo function in endocytic activity by transporting material of extrinsic origin to some of their granules which are thereby transformed to heterophagic bodies or constitute previously existing heterophagosomes.
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PMID:The heterophagic granules of mast cells: dipeptidyl aminopeptidase II activity and resistance to exocytosis. 42 34

The hemoglobin of the flatworm Dicrocoelium dendriticum, a lanceolate fluke which infests the hepatic ducts of certain mammals, has been isolated by gel filtration and ion-exchange chromatography. The molecular weight of the denatured protein was found to be 15500, a value in the same range as hemoglobin subunits. The fact that the native hemoglobin has an apparent molecular weight of 22000 in 0.01 M phosphate buffer, pH 7.4, suggests limited aggregation. The protein contains, as all other myoglobins and hemoglobins, one molecule of non-covalently associated ferroprotoporphyrin IX per polypeptide chain. It forms the same ligand derivatives with very similar spectral properties as vertebrate hemoglobins. The high oxygen affinity (p50 is 0.07--0.1 mmHg or 9.3--13.3 Pa at 20 degrees C and pH 7.0) and the absence of heme-heme interaction of (Hill coefficient nH=1.0) are properties which this heme protein shares with other monomeric hemoglobins from invertebrate and lower vertebrate organisms. The native hemoglobin exists in two forms, having isoelectric points of 4.51 and 4.53, which do not differ in their amino-acid compositions. Dansylation indicated that the amino-terminal amino-acid residue is alanine. The carboxy-terminal sequence, determined by carboxypeptidase A digestion of the globin, is -His-Ala-Leu.
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PMID:Isolation and characterization of the hemoglobin from the lanceolate fluke Dicrocoelium dendriticum. 68 24

Mast cell granules free of a surrounding membrane were isolated from water-lysed rat peritoneal and thoracic mast cells by differential centrifugation. The granules were depleted of their histamine by suspension in 10 mM sodium phosphate buffer and the sodium-charged granules then converted into the "hydrogen form" by repeated washing in slightly acid deionized water. The cation exchanger properties of the mast cell granules were investigated by testing the applicability of the Rothmund-Kornfeld equation for cation exchangers to the binding of Na+ and Hi+ ions to granule sites. The results lend further support to the view that the mast cell granule acts as a cation exchanger with the exchanger function localized to protein carboxyls in the protein-heparin complex of the granule matrix.
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PMID:On the cation exchanger properties of rat mast cell granules and their storage of histamine. 92 Feb 2

Nucleoside diphosphate (NDP) kinases have been found to be involved in a wide range of fundamental biological processes ranging from developmental control to signal transduction and metastasis. We have recently cloned and sequenced a cDNA encoding an NDP-kinase of the rat mucosal mast cell line RBL-2H3 [Hemmerich, S., Yarden, Y., & Pecht, I. (1992) Biochemistry (preceding paper in this issue)]. The enzyme itself has been isolated by means of its affinity to the bischromone cromoglycate. Here we report several of its biochemical characteristics: A structural model for the native protein is proposed in which two disulfide-linked pairs of similar 18-kDa subunits (p18) associate to form a 72-kDa tetramer (p72). This is based on the migration properties of the purified enzyme on gel filtration columns, sodium dodecylsulfate gel electrophoresis, and two-dimensional electrophoresis, together with peptide mapping data. In the absence of NDP, both intact p72 and the dissociated 18-kDa subunits (p18) were shown to undergo Mg(2+)-dependent stoichiometric autophosphorylation utilizing adenosine and guanosine triphosphate or gamma-thiotriphosphate as phosphate donor. This autophosphorylation activity was found to be retained by the 18-kDa subunits even following fractionation by SDS-PAGE and electrophoretic transfer to nitrocellulose. The Michaelis constant of this autophosphorylation reaction with either ATP, ATP gamma S, GTP, or GTP gamma S was determined to be 6.5 +/- 1 microM, and maximally 2 mol of phosphate were found to be incorporated per p72 molecule, thus indicating that phosphorylation occurs at a single site on only two of the four 18-kDa subunits of the holoenzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oligomeric structure and autophosphorylation of nucleoside diphosphate kinase from rat mucosal mast cells. 131 52

The relation between average duodenal mast cell count, duodenal mucosal mast cell numbers, duodenal connective tissue mast cell numbers, circulating basophil numbers, heterophil-to-lymphocyte ratio, and lesion score were studied to gain an understanding of the events that may lead to intestinal lesion formation associated with hemorrhagic enteritis virus (HEV) infection. Changes in vascular permeability in the duodenum in birds inoculated with HEV were examined, using colloidal carbon and ferritin as vascular markers. Turkeys inoculated with HEV had significantly (P less than 0.05) higher duodenal mast cell counts than did noninfected controls. Birds inoculated with HEV had significantly (P less than 0.05) more mucosal mast cells than did phosphate-buffered saline solution-inoculated birds. Connective tissue mast cell and basophil numbers were unaffected by viral inoculation. Thermal stress did not have significant effect on lesion severity, but did increase number of birds that developed the characteristic intestinal lesions. The heterophil-to-lymphocyte ratio was significantly (P less than 0.05) higher in HEV-inoculated birds, compared with phosphate-buffered saline solution-inoculated controls. Increase in vascular permeability was only detected in HEV-inoculated birds with intestinal lesions. Results indicate that mast cells, and the vasoactive mediators contained within mast cells, may be important in the early manifestation of HEV infection. They also provide a possible mechanism through which biochemical and physiologic changes characteristic of HEV infection can occur.
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PMID:Increased numbers of duodenal mucosal mast cells in turkeys inoculated with hemorrhagic enteritis virus. 132 44

This study examined cutaneous mast cell behaviour in 14 patients with chronic urticaria but no dermographism and 11 healthy controls, by measuring cutaneous weal and flare reactions evoked in response to intradermal challenge injections of 0.1 ml isotonic saline, histamine (20 micrograms), codeine phosphate (10 micrograms) and compound 48/80 (10 micrograms). Five minutes after each injection, the area of the resulting weal and flare was calculated by computer-aided planimetry. The process was repeated at 15, 30 and 45 min following the injection. In patients, saline flares were significantly larger than those of the volunteers at 15, 30 and 45 min (p < 0.05). However, histamine and codeine flare areas were significantly smaller in the patients when compared to the controls at 15, 30 and 45 min (p < 0.05). Compound 48/80 produced smaller reactions in the patients without reaching statistical significance.
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PMID:Aberrant cutaneous weal and flare responses in chronic urticaria. 136 42

Mast cells may be more abundant in the tissues of uremic patients and may contribute to itching via mediator release. Because mast cell (MC) granule release may be inhibited by ultraviolet B (UVB) radiation, we investigated skin MC in the superficial dermis by quantitative histomorphometry before and after whole body UVB for uremic itching. Toluidine blue-stained 3.5 mm punch biopsy specimens were examined with a micrometer grid after separate coding. Upon entry to the study, itching dialysis patients indicated their itching intensity on a visual analog scale (0 to 10). Concurrent study of living, related kidney donors (controls, n = 11) and their recipients (n = 11) showed no differences in MC number per unit area. Compared to controls, skin MC number was not greater in itching dialysis patients (n = 20). MC number decreased after 2 months of UVB from 1.6 +/- 0.6 (standard deviation) to 1.0 +/- 0.7 (n = 11, p = 0.025). Pre-UVB total plasma calcium correlated directly with itching intensity, but not with MC number. Plasma phosphate and intact parathyrin level were not statistically related to itching or MC number. Of the 14 subjects that completed UVB, 8 had objective benefit, and mean itching intensity declined from 7.1/10 to 5.2/10 in the 14 subjects. The conclusion is that although skin MC number may decline with chronic UVB, MC number is not related to uremic itching, and hypercalcemia, but not elevation of parathyrin or plasma phosphate, relates statistically to severe uremic itching.
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PMID:Mast cells and calcium in severe uremic itching. 160 64


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