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)

Carboxypeptidase A gamma from porcine pancreas was purified to homogeneity by ammonium sulfate fractionation, autolysis, batch absorption and elution from DEAF-Sephadex, and crystallization. The overall purification was about 32-fold with a yield of 31% and the specific activity of the purified protein was 108 units/mg protein. The apparent relative molecular mass determined by gel filtration on a Sephadex G-200 column was 38 900. The amino-terminal sequence of the porcine carboxypeptidase A gamma was Asn-Tyr-Ala-Thr-Tyr-His-Thr-Leu-Glu-Glu-Ile-Tyr-Asp-Phe-Met-Asp-Ile-Leu-Val-Ala -Glu-His-Pro-Gln-Leu- which was highly homologous to that of bovine carboxypeptidase A gamma. The purified enzyme was characterized with respect to isoelectric point (4.3). Km for N alpha-carbobenzoxyglycyl-L-phenylalanine (Cbz-Gly-LPhe) (20 mM), amino acid composition, pH optimum, pH stability, stability at different temperatures and effect of drying. The enzyme contained 1.01 mol zinc/mol and was inhibited by chelating agents such as EDTA and o-phenanthroline. Among substrates such as Cbz-Gly-LPhe, N alpha-benzoylglycyl-L-arginine, various kinds of amino acid esters, casein and elastin, porcine carboxypeptidase A gamma showed an enzymatic activity only towards Cbz-Gly-LPhe and casein. These data are in good agreement with the substrate specificity of bovine carboxypeptidase A.
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PMID:Crystallization and properties of carboxypeptidase A gamma from porcine pancreas. 727 15

The synthesis of the mast cell-degranulating peptide by liquid-phase fragment condensation is described. After the carboxyterminal of the peptide is condensated with polyethylene-glycol (Mr 10000) the following fragments are coupled stepwise on the polymer, a soluble carrier in dichloromethane by the dicyclohexylcarbodiimide/hydroxybenzotriazole-method. Pos. 17-21 Boc-Lys(Z)-Ile-Cys(SiPr)-Gly-Lys(Z) (I) Pos. 12-16 Boc-Pro-His(Trt)-Ile-Cys(Trt)-Arg(Tos) (II) Pos. 8-11 Boc-His(Trt)-Val-Ile-Lys(Z) (III) Pos. 5-7 Boc-Cys(SiPr)-Lys(Z)-Arg(Tos) (IV) Pos. 1-4 Boc-Ile-Lys(Z)-Cys(Trt)-Asn(Mbh) (V) It is practical to crystallize the polyethyleneglycol peptide-coupling products from ethanol after each step. Most of the protecting groups can be removed by treatment of the complete polyethylene-glycol-peptide in trifluoroacetic acid/HBr. In methanol, saturated with ammonia, the peptide is removed in the amid-form from the carrier. The guanidyl-blocking group disappears by solving the peptide in liquid HF. The crude peptide is converted into the tetra-S-sulfonate derivate by oxidative sulfitolysis and purified by ion-exchange and gel chromatography. After reduction by mercaptoethanol a cautious air-reoxidation of the SH- to the SS-peptide followed. Rechromatography on ion-exchange and dextran gels yields a peptide with good biological activity in rat cell histamin-liberation and inflammation inhibition compared with the natural recombinated product.
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PMID:[Basic peptides from bee venom, IV. Synthesis of the mast cell-degranulating peptide by liquid-phase fragment condensation (author's transl)]. 738 Mar 91

The basic helix-loop-helix (bHLH) transcription factors form heterodimers and control steps in cellular differentiation. We have studied four bHLH transcription factors, SCL, lyl-1, E12/E47, and ld-1, in individual lineage-defined progenitors and hematopoietic growth factor-dependent cell lines, evaluating mRNA expression and the effects of growth factors and cell cycle phase on this expression. Single lineage-defined progenitors selected from early murine colony starts and grown under permissive conditions were analyzed by RT-PCR. SCL and E12/E47 were expressed in the vast majority of tri-, bi-, and unilineage progenitors of erythroid, macrophage, megakaryocyte, and neutrophil lineages. Expression for E12/E47 was not seen in unilineage megakaryocyte and erythroid or bilineage neutrophil/mast cell progenitors. Lyl-1 showed a more restricted pattern of expression, although expression was seen in some bi- and unilineage progenitors. No expression was detected in erythroid, erythroid-megakaryocyte-macrophage, macrophage-neutrophil, macrophage, or megakaryocytic progenitors. Id-1, an inhibitory bHLH transcription factor, was also widely expressed in all bi- and unilineage progenitors; only the trilineage erythroid-megakaryocyte-macrophage progenitors failed to show expression. Expression of these factors within a progenitor class was generally heterogeneous, with some progenitors showing expression and some not. This was seen even when two sister cells from the same colony start were analyzed. Id-1, but not E12/E47, mRNA was increased in FDC-P1 and MO7E hematopoietic cell lines after exposure to IL-3 or GM-CSF. Id-1, E12, and lyl-1 showed marked variation at different points in cell cycle in isoleucine-synchronized FDC-P1 cells. These results suggest that SCL, lyl-1, E12/E47, and Id-1 are important in hematopoietic progenitor cell regulation, and that their expression in hematopoietic cells varies in response to cytokines and/or during transit through cell cycle.
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PMID:Expression of basic helix-loop-helix transcription factors in explant hematopoietic progenitors. 876 52

Endothelin (ET-1) is a 21-amino acid, vasoconstrictive peptide originally isolated from endothelial cells. It is one member of a class of potent, purportedly paracrine substances that act at receptors in multiple target organs. Antagonists to the receptor subtypes, ETA and ETB, have been designed around the hydrophobic carboxy-terminus of ET-1. The resulting hexapeptides possess low nanomolar receptor affinity, but face formidable challenges to oral delivery, given their peptidic nature. Hence, it was important to discriminate between analogs, as well as to optimize structural features combining binding potency with stability in intestinal fluids and permeability across biological membranes. PD 142893 (Ac-DDip16-Leu-Asp-Ile-Trp21) and PD 145065 (Ac-DBhg16-Leu-Asp-Ile-Ile-Trp21), as well as the N-methyl-isoleucine20 analogs were studies, where DDip = 3,3diphenylalanine and DBhg = 10,11-dihydro-5H-dibenzo[a,d]cycloheptene glycine. Analyses were conducted with specific HPLC methods. Permeabilities across CACO-2 cell monolayers ranged from 2.0x10(-4) to 6.3x10(-4)cm/min. The results suggested that these compounds can be absorbed in vivo, based on comparison of permeabilities with those obtained with reference compounds. Much greater differences were observed between the analogs when stability half-lives were compared after incubation in rat intestinal perfusate. The parent peptides, PD 142893 and PD 145065, were unstable, with half-lives less than 20 min. N-Methylation of Ile20 resulted in large increases in stability half-lives to greater 500 min. Enzyme inhibition studies demonstrated the involvement of carboxypeptidase A in production of the primary metabolite, the des-Trp derivative. Identification of the primary metabolite of the parent peptide was made by differential UV scanning at 214/280 nm and mass spectral analyses.
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PMID:In vitro assessment of oral delivery for hexapeptide endothelin antagonists. 878 9

Human chymase and rat chymase-1 are mast cell serine proteases involved in angiotensin II (Ang II) formation and degradation, respectively. Previous studies indicate that both these enzymes have similar P1 and P2 preferences, which are the major determinants of specificity. Surprisingly, despite the occurrence of optimal P2 and P1 residues at the Phe8 downward arrow and Tyr4 downward arrow bonds (where downward arrow, indicates the scissile bond in peptide substrates) in Ang I (DRVYIHPFHL), human chymase cleaves the Phe8 downward arrow bond with an approximately 750-fold higher catalytic efficiency (kcat/Km) than the Tyr4 downward arrow bond in Ang II (DRVYIHPF), whereas rat chymase-1 cleaves the Tyr4 downward arrow bond with an approximately 20-fold higher catalytic efficiency than the Phe8 downward arrow bond. Differences in the acyl groups IHPF and DRVY at the Phe8 downward arrow and Tyr4 downward arrow bonds, respectively, are chiefly responsible for the preference of human chymase for the Phe8 downward arrow bond. We show that the IHPF sequence forms an optimal acyl group, primarily through synergistic interactions between neighboring acyl group residues. In contrast to human chymase, rat chymase-1 shows a preference for the Tyr4 downward arrow bond, mainly because of a catalytically productive interaction between the enzyme and the P'1 Ile5. The overall effect of this P'1 Ile interaction on catalytic efficiency, however, is influenced by the structure of the acyl group and that of the other leaving group residues. For human chymase, the P'1 Ile interaction is not productive. Thus, specificity for Ang II formation versus Ang II degradation by these chymases is produced through synergistic interactions between acyl or leaving group residues as well as between the acyl and leaving groups. These observations indicate that nonadditive interactions between the extended substrate binding site of human chymase or rat chymase-1 and the substrate are best explained if the entire binding site is taken as an entity rather than as a collection of distinct subsites.
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PMID:Distinct multisite synergistic interactions determine substrate specificities of human chymase and rat chymase-1 for angiotensin II formation and degradation. 900 43

The rat basophilic leukaemia (RBL) cell line has been widely used as a convenient model system to study regulated secretion in mast cells. Activation of these cells through the high-affinity receptor for IgE (Fcepsilon-RI) results in degranulation and the extracellular release of mediators. There is good evidence of a role for GTPases in mast cell degranulation, and a number of studies with peptides derived from the Rab3a effector domain have suggested that Rab3a may function in this process. However, in neuroendocrine cells, overexpression of Rab3a can act as a negative regulator of stimulated exocytosis [Holz, Brondyk, Senter, Kuizon and Macara (1994) J. Biol. Chem. 269, 10229-10234; Johanes, Lledo, Roa, Vincent, Henry and Darchen (1994) EMBO J. 13, 2029-2037]. In order to study the function of Rab3a in RBL degranulation, we have generated clones of RBL cells stably expressing Rab3a, and show that in these haematopoietic cells Rab3a can also function as a negative regulator of exocytosis. Overexpression of a mutant form of Rab3a (Asn-135 to Ile), which is predicted to be predominantly GTP-bound, also inhibited degranulation. However, overexpression of a mutant form of Rab3a that was truncated at the C-terminus to remove the sites for geranylgeranylation failed to inhibit degranulation. The effect of Rab3a is specific to secretion, and we observe no effect of Rab3a on receptor-mediated endocytosis. The Rab3a-induced block in degranulation can be bypassed by stimulation of streptolysin-O-permeabilized cells with guanosine 5'-[gamma-thio]triphosphate. We conclude from these studies that Rab3a is implicated in an early stage of granule targeting, whereas fusion of granules with the plasma membrane is regulated by a distinct downstream GTP-binding protein or proteins.
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PMID:Rat basophilic leukaemia (RBL) cells overexpressing Rab3a have a reversible block in antigen-stimulated exocytosis. 916 19

1. Atopy is a genetically heterogeneous disorder, but there is now strong evidence that one important locus is on chromosome 11q13. Fc epsilon RI-beta at that location has been identified as a candidate gene and variants have been associated with atopy in population studies. 2. No information is available on the functional consequences of any of these variants, and defining this may prove difficult because of the complexity of the atopy phenotype and because Fc epsilon RI beta is expressed on a range of cells with different functions, including basophils, mast cells, eosinophils and antigen-presenting Langerhan's cells. 3. We have conducted a qualitative study of mast cell and basophil histamine release in nine atopic individuals with Ile-181-->Leu mutation of Fc epsilon RI beta, and ten unrelated similarly atopic individuals without Ile-181-->Leu mutation. There were non-significant trends for Ile-181-->Leu-positive atopic subjects to produce wheal responses at lower allergen challenge in skin prick tests, and to release more histamine from basophils following in vitro allergen challenge. 4. The data do not provide decisive evidence of functional differences between atopic subjects with Ile-181-->Leu and other atopic individuals; more discriminating functional experiments are required.
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PMID:Functional analysis of histamine release from basophils and mast cells in subjects with the Ile-181-->Leu variant of Fc epsilon RI-beta. 933 44

The carboxypeptidase A-catalyzed syntheses of dipeptides from L-amino acids (Phe, Tyr, Trp, Leu and Ile) were studied in various water-miscible (acetone, acetonitrile, ethanol, methanol and 1,4-dioxane) organic solvents. The highest yield (43%) was achieved in acetonitrile with L-Phe as substrate, after a 24-h incubation. The optimal conditions of Phe-Phe synthesis in acetonitrile were determined. For maximal conversion 1.2 mM L-Phe, 1.4 mg ml-1 enzyme and about 10% water are needed in buffered aqueous acetonitrile (pH 5.5) at 30 degrees C.
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PMID:Carboxypeptidase A-catalyzed dipeptide synthesis in organic media. 986 61

There has long been evidence that inhibitors of chymotryptic proteinases can inhibit the degranulation of rodent mast cells, but their actions on human mast cells and the contribution of mast cell chymase itself have received little attention. We investigated the ability of the selective chymase inhibitor Z-Ile-Glu-Pro-Phe-CO(2)Me and other proteinase inhibitors to inhibit chymase and cathepsin G activity, and we examined their potential to modulate the responsiveness of mast cells dispersed from human skin, lung, and tonsil tissues. IgE-dependent histamine release from skin mast cells was inhibited by up to about 80% after preincubation with Z-Ile-Glu-Pro-Phe- CO(2)Me (up to 0.1 microM), 70% with chymostatin (17 microM), and 60% with soybean trypsin inhibitor (0.5 microM). The mast cell-stabilizing properties of chymase inhibitors appeared to be greater for skin mast cells than for those from lung, whereas tonsil mast cells were relatively unresponsive. There were marked differences in the time course of responses to inhibitors, and the effect was dependent on the stimulus, with calcium ionophore-induced histamine release being unaffected. Incubation of dispersed skin, lung, or tonsil cells for up to 45 min with purified chymase failed to induce histamine release, although preincubation of cells with chymase was able to suppress IgE-dependent activation. Chymase could thus contribute to mast cell degranulation and after secretion could provide a feedback mechanism to limit this process. Nevertheless, inhibitors of chymase can be potent mast cell stabilizers, particularly in the skin.
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PMID:Inhibitors of chymase as mast cell-stabilizing agents: contribution of chymase in the activation of human mast cells. 1052 66

Clustering of the mast cell function-associated antigen by its specific monoclonal antibody (G63) inhibits the FcepsilonRI-mediated secretory response. The cytosolic tail of the mast cell function-associated antigen contains a SIYSTL stretch, a potential immunoreceptor tyrosine-based inhibition motif. To investigate the possible functional role of this sequence, as well as identify potential intracellular proteins that interact with it, peptides corresponding to residues 4-12 of the mast cell function-associated antigen's N-terminal cytoplasmic domain, containing the above motif, were synthesized and used in affinity chromatography of mast cell lysates. Both tyrosyl phosphorylated and thiophosphorylated mast cell function-associated antigen peptides bound the src homology domain 2 (SH2)-containing tyrosine phosphatases-1 (SHP-1), -2 (SHP-2) and inositol 5'-phosphatase (SHIP), though with different efficiencies. Neither the nonphosphorylated peptide nor its tyrosyl phosphorylated reversed sequence peptide bound any of these phosphatases. Point mutation analysis of mast cell function-associated antigen pITIM binding requirements demonstrated that for SHP-2 association the amino acid residue at position Y-2 is not restricted to the hydrophobic isoleucine or valine. Glycine and other amino acids with hydrophilic residues, such as serine and threonine, at this position also maintain this binding capacity, whereas alanine and acidic residues abolish it. In contrast, SHP-1 binding was maintained only when serine was substituted by valine, suggesting that the Y-2 position provides selectivity for peptide binding to SH2 domains of SHP-1 and SHP-2. These results were corroborated by surface plasmon resonance measurements of the interaction between tyrosyl phosphorylated mast cell function-associated antigen peptide and recombinant soluble SH2 domains of SHP-1, SHP-2 and SHIP, suggesting that the associations observed in the cell lysates may be direct. Taken together these results clearly indicate that the SIYSTL motif present in mast cell function-associated antigen's cytosolic tail exhibits characteristic features of an immunoreceptor tyrosine-based inhibition motif, suggesting it is a new member of the growing diverse family of immunoreceptor tyrosine-based inhibition motif-containing receptors.
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PMID:An immunoreceptor tyrosine-based inhibitory motif, with serine at site Y-2, binds SH2-domain-containing phosphatases. 1065 6


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