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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serine class proteinases with trypsin-like and chymotrypsin-like specificity were purified from dog mastocytoma tissue. An antiserum was produced against the chymotrypsin-like proteinase. The antiserum reacted with mast cells in skin sections prepared from normal dogs consistent with the proteinase being a mast cell constituent. The antiserum also cross-reacted with the major chymotrypsin-like proteinase isolated from normal dog skin and partially cross-reacted with human skin chymase. No cross-reaction was detected with rat chymase. The trypsin-like proteinase from dog mastocytoma tissue was similar to tryptase isolated from human skin. It had a similar subunit structure, was not inhibited by many protein proteolytic enzyme inhibitors, bound to heparin, and reacted strongly with antiserum against human tryptase. Antiserum against human tryptase also reacted with mast cells in skin sections prepared from normal dog skin. No immunocytochemical labeling of rat skin mast cells was observed with anti-human tryptase. These studies establish the presence of a trypsin-like and chymotrypsin-like proteinase in dog skin mast cells and provide immunological evidence which suggests that both proteinases are more closely related to human than rat mast cell proteinases. These immunological and biochemical relationships are important when comparing the roles of these proteinases in different animals.
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PMID:Purification and identification of two serine class proteinases from dog mast biochemically and immunologically similar to human proteinases tryptase and chymase. 312 77

Mast cell populations can be distinguished by differences in the content and substrate specificity of their two major cytoplasmic granule proteases, the chymases and the tryptases. To explore the origins of differences in the types of proteases present in mast cells, we used a double cytochemical staining technique to reveal both chymase and tryptase in cells from four lines of dog mast cell tumors containing both enzymes. We expected that if chymase and tryptase were expressed together during cell development the relative staining intensity of chymase compared to tryptase would be constant among different cells of each tumor. Instead, we found substantial variation in the relative intensity of chymase and tryptase staining among cells of a given mastocytoma line, each of which contained cells presumed to be monoclonal in origin but heterogeneous with respect to cell development. The overall staining intensity for chymase or tryptase correlated with the amount of protease activity in extracts of tumor homogenates. Staining specificity was established by use of selective inhibitors and competitive substrates and was tested on various types of dog cells obtained by bronchoalveolar lavage. The results suggest that active chymase and tryptase may be expressed differently during mast cell differentiation and support the possibility of a close developmental relationship between mast cells differing in protease phenotype. Moreover, the success of the staining procedures applied to mastocytoma cells suggests that they may be of general utility in phenotyping of mast cells according to the protease activities present in their granules.
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PMID:Chymase and tryptase in dog mastocytoma cells: asynchronous expression as revealed by enzyme cytochemical staining. 313 86

We have previously shown that a confluent layer of mature mast cells is obtained when lymph node cells are grown on embryonic fibroblast monolayers. Two populations of mast cells may be observed, depending on treatment of the mice from which the lymph node cells are derived. We report now on the morphometric evaluation of these two mast cell entities, and we correlate this with cellular biochemistry and secretory behaviour. The first type of mast cell is small (265 +/- 20 microns 3). It arises from the embryonic monolayer and the cells have feathers resembling those of connective tissue mast cells. These cultured cells are filled with about 1000 homogeneous electron-dense granules, which usually range in diameter from 0.05 to 0.2 microns. The second type of mast cell arises from precursors originating from the lymph node and they have feathers of mucosal mast cells. These cells are larger (480 +/- 40 microns 3) and contain about 300 heterogeneous granules, which range from 0.1 to 0.8 microns. Both cell entities contain about equal amounts of histamine, serotonin and chymase. Biologically, the two cell entities secrete soluble mediators (histamine and serotonin) at different rates compared to the rate at which they secrete chymase. We suggest that such a pattern of secretion exhibits a form of degranulation that permits the release of freely diffusible mediators that are loosely bound to granules, but only partially permits the secretion of insoluble mediators, which are stored in the granules. Alternatively, there might be a mechanism that rapidly inactivates or binds chymase so that only the vasoamines will be free.
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PMID:Two populations of mast cells on fibroblast monolayers: correlation of quantitative microscopy and functional activity. 325 2

The distribution and concentration of human T (tryptase-positive, chymase-negative) and TC (tryptase-positive, chymase-positive) mast cells were examined in Carnoy's-fixed specimens of the gastrointestinal tract of normal individuals, patients with inflammatory bowel diseases, and patients with immunodeficiency disorders. In normal specimens, T mast cells predominated in the mucosa (89%), with a mean concentration of 17,850 +/- 4,998 per mm3 (+/- SD, n = 16), whereas TC mast cells predominated in the submucosa (90%) with a mean concentration of 7,516 +/- 1,227 per mm3 (+/- SD, n = 16). The concentrations of T and TC mast cells in specimens of ileum from five patients with active Crohn's disease and of colon from three patients with active ulcerative colitis were not significantly different (p greater than 0.4) from normal values. Three patients with combined immunodeficiency disorders demonstrated a marked decrease in the concentration of the T mast cells in the intestinal mucosa, to 540 +/- 630, and a corresponding decrease in the percentage of T mast cells to 9%. Concentrations of TC mast cells were unchanged, both in the mucosa and in the submucosa. In three patients with acquired immunodeficiency syndrome, a similar deficiency of the T mast cell type was observed in the ileal mucosa, with a mean concentration of 788 +/- 534 T mast cells per mm3, but not in the appendiceal and colonic mucosa of one of the three patients. These findings indicate a role for functional T lymphocytes in the development of the T mast cell type in humans, and suggest divergent pathways for development of T and TC mast cells.
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PMID:Deficiency of the tryptase-positive, chymase-negative mast cell type in gastrointestinal mucosa of patients with defective T lymphocyte function. 329 46

The distribution of mast cell granule proteinases in the rat digestive system was determined immunohistochemically. The population of toluidine blue-staining mast cells was accounted for by cells containing either rat mast cell proteinase I (RMCPI) or rat mast cell proteinase II (RMCPII). Granules in greater than 90% of RMCPI-containing cells stained red after the Alcian blue/safranin sequence, whereas all RMCPII-containing mast cells stained blue. The red/RMCPI phenotype was typical of the connective tissue mast cells (CTMC) that populate the proximal, non-mucosal, regions of the digestive system, and was also abundant in the serosa and in rectal and gastric muscularis. The blue/RMCPII phenotype, absent from non-mucosal sites except for rare cells in intestinal submucosa and muscularis, predominated in all mucosal tissues and resembled mucosal mast cells (MMC). A third, minor population of cells containing RMCPI but staining blue in the Alcian blue/safranin sequence was detected in both non-mucosal and mucosal tissues. Blue/RMCPI mast cells were rare in the small intestine but more frequent in the mucosa of the stomach and large intestine and in the connective tissues. It is suggested that granule proteinase phenotyping may provide an alternative technique in the analysis of mast cell heterogeneity.
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PMID:Phenotypic expression of mast cell granule proteinases. Distribution of mast cell proteinases I and II in the rat digestive system. 332 33

The secretory granules of rat serosal mast cells are able efficiently to degrade the apolipoprotein B component of low density lipoproteins (LDL) Kokkonen, J. O., and Kovanen, P. T. (1985) J. Biol. Chem. 260, 14756-14763). The granules are known to contain two neutral proteases with complementary specificities: a chymotrypsin-like endopeptidase called chymase, and an exopeptidase, the granule carboxypeptidase A. The role of this enzyme pair in the proteolytic degradation of LDL was studied with the aid of specific enzyme inhibitors. Incubation of LDL with intact granules (both enzymes active) led to the formation of numerous low molecular weight peptides and the liberation of free amino acids, most of which (95%) were aromatic (Phe, Tyr, Trp) or branched-chain aliphatic (Leu, Ile, Val). Selective inhibition of granule carboxypeptidase A (leaving chymase active) blocked the liberation of free amino acids, but left the formation of peptides uninhibited. On the other hand, selective inhibition of granule chymase (leaving carboxypeptidase A active) totally abolished the proteolytic degradation of LDL. The results are consistent with a model according to which the proteolytic degradation of LDL by mast cell granules results from coordinated action of the two granule-bound enzymes, whereby the chymase first cleaves peptides from the apolipoprotein B of LDL, and thereafter the carboxypeptidase A cleaves amino acids from the peptides formed.
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PMID:Low density lipoprotein degradation by secretory granules of rat mast cells. Sequential degradation of apolipoprotein B by granule chymase and carboxypeptidase A. 353 21

Levels of histamine, chymase, and tryptase were assessed in preparations of dispersed human TC (tryptase+, chymase+) mast cells obtained from foreskin and of dispersed human T (tryptase+, chymase-) mast cells obtained from lung. Consistent with previous immunohistochemical results, extracts of T mast cells, the predominant mast cell type in lung (93% T and 7% TC mast cells), were deficient in human chymase (less than 0.3 microgram and 0.04 U/10(6) mast cells) but not tryptase (10.8 micrograms and 0.3 U/10(6) mast cells) by corresponding immunologic and enzymatic (suc-L-ala-ala-pro-phe-p-nitroanilide in the presence of aprotinin and tosyl-L-gly-pro-lys-p-nitroanilide in the presence of soybean trypsin inhibitor, respectively) assays. The minor presence of chymase activity in lung could be accounted for by the minor presence of lung TC mast cells. Extracts of TC mast cells, the predominant mast cell type (1% T and 99% TC mast cells) in foreskin, contained both proteases. However, TC mast cells from adult foreskin contained eightfold to 10-fold higher levels of chymase (4.5 micrograms and 1.01 U/10(6) mast cells) and twofold to threefold higher levels of tryptase (11.5 micrograms and 0.27 U/10(6) mast cells) than did TC mast cells from newborn foreskin (less than 0.6 microgram and 0.09 U of chymase and 35 micrograms and 0.62 U of tryptase/10(6) mast cells). In contrast, histamine levels were not significantly different in adult foreskin TC (1.9 microgram/10(6) mast cells), newborn foreskin TC (1.6 microgram/10(6) mast cells), and adult lung T (1.5 microgram/10(6) mast cells) mast cells. The relative ratio of each mediator in newborn foreskin mast cells to that in adult foreskin mast cells is highest for histamine, followed by tryptase and then chymase. Tryptase from TC and T mast cells had identical subunit compositions by Western blot analysis and similar apparent specific activities. This study extends the previously reported immunohistochemical distinction between human T and TC mast cells in tissue sections by direct quantitation of chymase and tryptase in dispersed preparations of T and TC mast cells.
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PMID:Quantitation of histamine, tryptase, and chymase in dispersed human T and TC mast cells. 354 3

The subcellular localization of human skin chymase to mast cell granules was established by immunoelectron microscopy, and binding of chymase to the area of the dermo-epidermal junction, a basement membrane, was demonstrated immunocytochemically in cryosections incubated with purified proteinase prior to immunolabeling. Because heparin and heparan sulfate proteoglycans are major constituents of mast cell granules and basement membranes, respectively, the ability of chymase to bind to glycosaminoglycans (GAG) was investigated. Among a variety of GAGs, only binding of chymase to heparin and heparan sulfate appears physiologically significant. Binding was ionic strength-dependent, involved amino groups on the proteinase, and correlated with increasing GAG sulfate content, indicating a predominantly electrostatic association. Interaction with heparin was observed in solutions containing up to 0.5 M NaCl, and interaction with heparan sulfate was observed in solutions containing up to 0.3 M NaCl. Binding of heparin did not detectably affect catalysis of peptide substrates, but may reduce accessibility of proteinase to protein substrates. Measurements among a series of serine class proteinases indicated that heparin binding was a more common property of mast cell proteinases than proteinases stored in other secretory granules. Binding of chymase to heparin is likely to have a storage as well as a structural role within the mast cell granule, whereas binding of chymase to heparan sulfate may have physiological significance after degranulation.
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PMID:Human skin chymotrypsin-like proteinase chymase. Subcellular localization to mast cell granules and interaction with heparin and other glycosaminoglycans. 355 92

Intradermal injections of isolated mast cell granules (MCGs), as well as solubilized high-molecular-weight (HMW) (greater than 10,000 daltons) and low-molecular-weight (LMW) (10,000 greater than MW greater than 500 daltons) fractionated granule constituents, can produce inflammatory responses termed late-phase reactions (LPRs). The identity and mechanism of action of various inflammatory factor(s) contained within these fractions is incompletely established. Since rat LPRs are neutrophil-dependent responses, we analyzed the inherent neutrophil chemoattractant potential of HMW and LMW granule fractions using a 48-well microchemotaxis chamber. Although both HMW and LMW fractions attracted rat neutrophils, the LMW fraction was less active at equivalent protein concentrations. Checkerboard analysis demonstrated that the HMW fraction enhanced random migration of neutrophils, indicating that the HMW fraction contains factors that are primarily chemokinetic. To analyze further the HMW fraction, solubilized MCGs were sequentially fractionated with XM300 (MW greater than 300,000 daltons), and YM100 (300,000 greater than MW greater than 100,000 daltons), XM50 (100,000 greater than MW greater than 50,000 daltons), and YM10 (50,000 greater than MW greater than 10,000 daltons) ultrafiltration membranes. This process revealed that most in vivo inflammation-provoking activity as well as the in vitro chemoattractant activity resided in the XM300 and YM100 retentate fractions. Two of the major constituents of the HMW fraction, heparin and chymase, were evaluated for their contribution to the chemoattraction. Purified MCG heparin did not evoke neutrophil migratory responses in vitro or in vivo. Sepharose 4B chromatography of solubilized MCG demonstrated a peak of inflammation-provoking activity beginning at the void volume and tapering off near the 400,000 MW range. This in vivo activity was clearly separable from the chymase activity and represents the HMW inflammatory factors. These results demonstrate that both HMW and LMW granule fractions contain inflammatory activities capable of producing LPR in vivo and suggest that enhancement of neutrophil migration at sites of mast cell degranulation is one mechanism of action.
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PMID:The biologic activity of mast cell granules. VIII. In vivo and in vitro characterization of mast cell granule-derived inflammatory factors involved in rat late-phase reactions. 380 45

The activity of chymase was markedly inhibited by phosphoglycerides such as phosphatidic acid, phosphatidylserine, and phosphatidylinositol, but was not affected by acylglycerides, phosphoglyceroserine, serine, inositol, or glycerol. These results suggest that both the nonpolar hydrophobic hydrocarbon tails and the polar hydrophilic head are essential for the inhibitory effects of phosphoglycerides. Binding of a primary amine to an anionic polar head of phosphatidic acid, such as in phosphatidylserine and phosphatidylethanolamine, slightly decreased the inhibitory effect of phosphatidic acid and, conversely, binding of a strong cation to the head, such as in phosphatidylcholine, resulted in its activation of chymase. Phosphatidic acid containing an unsaturated fatty acid, such as dioleoyl phosphatidic acid, caused the same extent of inhibition as natural phosphatidic acid from bovine brain, but was 20 times more inhibitory than phosphatidic acid containing a saturated fatty acid, such as distearoyl phosphatidic acid. The inhibition by phosphatidylserine was noncompetitive and pseudoirreversible, and the Ki value was 0.54 microM. The inhibition of chymase by phosphatidylserine was pH dependent, being strong at pH 8.5 to 9.5 but weak below pH 7.5. Phosphatidylserine specifically inhibited chymase and elastase; it did not inhibit the other chymotrypsin-type serine endopeptidases tested, trypsin, papain, collagenase, carboxypeptidase A, or cathepsin D.
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PMID:Inhibition of chymase activity by phosphoglycerides. 388 53


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