Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Based on bifunctional diketopiperazines as templates and m-aminomethyl-phenylalanine as arginine mimetic, we have synthesized a new class of structurally related dibasic tryptase inhibitors with systematically increasing spacer length. These compounds were used to scan the distance between the active sites of two neighboring subunits of the beta-tryptase tetramer. The K(i)-values obtained are a function of the distance between the terminal amino groups and indicate optimal binding of inhibitors with 29-31 bonds between the amino groups. These experimental data are in full agreement with predictions derived from a novel modeling program that allows the docking of bivalent ligands.
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PMID:Bivalent inhibition of beta-tryptase: distance scan of neighboring subunits by dibasic inhibitors. 1195 9

Abnormal differentiation and maturation of hemopoietic cells are characteristic features of myelodysplastic syndromes (MDS). Tryptases (alpha- and beta-type) are lineage-restricted serine proteases primarily expressed in mast cells (MC). We have analyzed expression of tryptase in 89 de novo MDS patients (refractory anemia (RA), n = 30; RA with ringed sideroblasts (RARS), n = 21; RA with excess of blasts (RAEB/RAEB-t), n = 27; chronic myelomonocytic leukemia (CMML), n = 11). Serum levels of total tryptase (alpha - protryptase + beta - tryptase) were measured by FIA. The numbers of tryptase+ cells were determined in paraffin-embedded bone marrow (bm) sections by immunohistochemistry and morphometry. In healthy individuals, serum total tryptase levels ranged between < 1 and 15 ng/ml (5.6 +/- 2.8 ng/ml). Tryptase levels of > 20 ng/ml were detected in 5/22 patients with RA (22.7%), 4/17 with RARS (23.5%), 0/16 with RAEB/RAEB-t, and 3/8 with CMML (37.5%). Thus, serum tryptase concentrations were higher in RA (16.6 +/- 14.3 ng/ml), RARS (12.9 +/- 8.2), and CMML (16.5 +/- 7.6) compared to RAEB/-t (8.7 +/- 3.8). By morphometry, elevated numbers of tryptase+ bm cells were detected in all MDS groups (RA: 139 +/- 131; RARS: 118 +/- 98; RAEB/RAEB-t: 80 +/- 79; CMML: 105 +/- 114 cells/mm2) compared to controls (54 +/- 51 cells/mm2). As assessed by Northern blotting and protein analysis, bm cells in MDS primarily produced alpha-(pro)tryptase, but little or no beta-tryptase. Together, our data show that elevated levels of tryptase are detectable in a group of patients with MDS probably because of an increase in neoplastic (mast) cells producing the enzyme(s). In addition, serum tryptase levels appear to correlate with MDS variants. Follow up studies should clarify whether an elevated tryptase concentration in MDS is of prognostic significance.
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PMID:Serum tryptase measurements in patients with myelodysplastic syndromes. 1214 92

Tryptase is a serine protease that is stored at low pH in the mast cell secretory granules in complex with heparin proteoglycan. When mast cells are activated, e.g. during allergic responses, the tryptase/heparin complexes are released together with a variety of other preformed inflammatory mediators. Previous crystallization of human beta-tryptase revealed a unique tetrameric structure with all of the active sites facing a central pore that has a limited accessibility both for potential substrates as well as for protease inhibitors. In this study we examined whether human beta-tryptase, in addition, could form active monomers. Incubation of recombinant tetrameric human beta-tryptase at neutral pH and 37 degrees C, followed by gel-filtration analysis using a running buffer containing pig mucosal heparin, led to the formation of enzymically active compounds that were of a size compatible with tryptase monomers in complex with heparin. The monomers were, in contrast to tryptase in the tetrameric form, inhibited by bovine pancreatic trypsin inhibitor. Further, the monomers, but not the tetramers, degraded fibronectin. Formation of active monomers was more pronounced at pH 7.5 than at pH 6.0 and was not detected at room temperature or at high heparin/tryptase ratios. The present findings thus introduce the possibility that human beta-tryptase, after mast cell degranulation and exposure to neutral pH in the tissue, may dissociate into active monomers with properties that are distinct from the tetrameric counterpart. Possibly, some of the biological activities of human tryptase may be attributable to active tryptase in its monomeric rather than tetrameric form.
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PMID:Formation of active monomers from tetrameric human beta-tryptase. 1238 26

Despite maturation arrest, blast cells in acute myeloid leukemia (AML) are often capable of expressing lineage-restricted (granulomonocytic or myelomastocytic) differentiation antigens. Tryptases are lineage-associated serine proteases primarily expressed in mast cells, and less abundantly in blood basophils. We have recently shown that myeloblasts in a group of patients with AML (approximately 40%) produce significant amounts of tryptase(s). In these patients, serum tryptase levels are elevated (> 15 ng/ml) and reflect the total burden of leukemic cells. In most cases, myeloblasts express alpha-tryptase mRNA in excess over beta-tryptase mRNA, and secrete the respective protein (= pro-alpha-tryptase) in a constitutive manner. It was also found that these AML blasts frequentlyco-express tryptase with additional mast cell lineage- and/or basophil-related differentiation antigens including KIT (CD117), histamine, and 2D7. We hypothesize that tryptase-positive AMLs arise from a leukemic progenitor that exhibits a limited potential to differentiate into mast cells and/or basophils.
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PMID:Tryptase a novel biochemical marker of acute myeloid leukemia. 1261 10

Tryptase (alpha and beta) levels in serum are used to assess mast cell involvement in human disease. Using cultured cells, the current study examines the hypothesis that protryptase(s) are spontaneously secreted by mast cells at rest, whereas mature tryptase(s) are stored in secretory granules until their release by activated cells. HMC-1 cells have only beta-tryptase genes and the corresponding mRNA. Mono-Mac-6 cells have both alpha- and beta-tryptase genes but preferentially express alpha-tryptase. Mono-Mac-6 cells spontaneously secrete most of their tryptase, which consists of alpha-protryptase, whereas mature tryptase is retained inside these cells. HMC-1 cells also spontaneously secrete most of their tryptase, identified as beta-protryptase, and retain mature tryptase. Skin-derived mast cells retain most of their tryptase, which is mature, and spontaneously secrete protryptase(s). Total tryptase levels in plasma are detectable but no different in healthy subjects with and without the gene for alpha-tryptase, consistent with pro forms of both alpha- and beta-tryptase being spontaneously secreted. Thus, protryptase(s) are spontaneously secreted by resting mast cells, whereas mature tryptase is retained by mast cells until they are activated to degranulate.
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PMID:Tryptase precursors are preferentially and spontaneously released, whereas mature tryptase is retained by HMC-1 cells, Mono-Mac-6 cells, and human skin-derived mast cells. 1275 48

We have identified a novel serine protease designated EOS by sequence identity searches. The deduced protein contains 284 amino acids with an active form containing 248 amino acids starting from an Ile-Val-Gly-Gly motif. The active form comprises a catalytic triad of conserved amino acids: His77, Asp126 and Ser231. It shares 44% identity with beta-tryptase and belongs to the S1 trypsin-like serine-protease family. Interestingly, this gene also maps to human chromosome 16p13.3. The purified protease showed amidolytic activity, cleaving its substrates before arginine residues. Tissue distribution by immunohistochemistry analysis demonstrated that EOS is highly expressed in spleen and moderately expressed in intestine, colon, lung and brain. We confirmed this expression pattern at the mRNA level by performing in situ hybridization. The results from both immunohistochemistry and in situ hybridization indicate that EOS is associated with macrophages. We corroborated this observation by double immunofluorescence using the anti-EOS antibody and an anti-CD68 antibody, a macrophage specific marker. Furthermore, we have detected a dramatic increase in immune staining of EOS in cultured U937 cells treated with PMA, which represent activated macrophages. This up-regulation is also reflected by elevated EOS mRNA in the PMA-treated U937 cells detected by Northern blotting. Since macrophages have important roles in various pathological conditions, such as wound healing, atherosclerosis and numerous inflammatory diseases, the localization of this novel serine protease to active macrophages may help to further the elucidation of the roles of this gene product in modulating these disorders.
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PMID:A novel serine protease predominately expressed in macrophages. 1279 36

Remodeling of extracellular matrix is an important component in a variety of inflammatory disorders as well as in normal physiological processes such as wound healing and angiogenesis. Previous investigations have identified the various matrix metalloproteases, e.g., gelatinases A and B, as key players in the degradation of extracellular matrix under such conditions. Here we show that an additional enzyme, human mast cell beta-tryptase, has potent gelatin-degrading properties, indicating a potential contribution of this protease to matrix degradation. Human beta-tryptase was shown to degrade gelatin both in solution and during gelatin zymographic analysis. Further, beta-tryptase was shown to degrade partially denatured collagen type I. beta-Tryptase bound strongly to gelatin, forming high molecular weight complexes that were stable during SDS-PAGE. Mast cells store large amounts of preformed, active tryptase in their secretory granules. Considering the location of mast cells in connective tissues and the recently recognized role of mast cells in disorders in which connective tissue degradation is a key event, e.g., rheumatoid arthritis, it is thus likely that tryptase may contribute to extracellular matrix-degrading processes in vivo.
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PMID:Human mast cell beta-tryptase is a gelatinase. 1287 42

SERPINB6 (PI6) is a member of the intracellular serine protease inhibitors (serpins). Previous studies showed that SERPINB6 is localized mainly in the cytoplasm of endothelial cells, some epithelial cells, monocytes, and neutrophils. In these cells SERPINB6 is thought to prevent cellular damage by scavenging leaking lysosomal proteases. We show here, using novel, well-defined monoclonal antibodies, that SERPINB6 is abundantly expressed by mast cells in all organs and by the human mast cell line HMC-1. Gel filtration experiments revealed that the latter cells contain a high-molecular-weight form of SERPINB6, which consists of sodium dodecyl sulfate (SDS)-stable complexes of this inhibitor with monomeric beta-tryptase. Expression of SERPINB6 by mast cells was compared with those of tryptase and CD117 (c-kit) in biopsies from patients with different forms of mast cell disease. In all cases the lesional mast cells expressed SERPINB6, and, in diffuse cutaneous mastocytosis and mastocytoma, SERPINB6 was expressed by a substantially higher number of mast cells when compared with tryptase. In conclusion, SERPINB6 is abundantly expressed by normal mast cells and by mast cells in mastocytoma lesions. We suggest that in mast cells, SERPINB6 serves to regulate the activity of endogenous beta-tryptase in the cytoplasm.
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PMID:Intracellular serpin SERPINB6 (PI6) is abundantly expressed by human mast cells and forms complexes with beta-tryptase monomers. 1467 Sep 19

An elevated serum tryptase concentration is considered to be a specific marker for systemic mast-cell activation, a central feature of anaphylaxis, which has been observed in some cases of sudden infant death syndrome (SIDS). However, it is still unclear whether anaphylaxis is involved in the etiology for SIDS. In the present study, we measured serum tryptase levels in 21 infants with SIDS, and 14 control infants from forensic autopsy cases by Uni-CAP TRYPTASE Fluoroenzyme immunoassay system, which detects both alpha- and beta-tryptase. The assay did not show any significant elevation of tryptase levels in the SIDS group compared with controls. Additionally, increased concentrations of tryptase were not observed in any SIDS case. Our results indicated that anaphylaxis does not seem to be involved in the etiology of SIDS.
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PMID:Serum tryptase levels in sudden infant death syndrome in forensic autopsy cases. 1468 74

beta-Tryptase is a trypsin-like serine protease stored in mast cell secretory granules primarily as an enzymatically active tetramer. The current study aims to determine whether monomeric beta-tryptase also can exhibit enzyme activity, as suggested previously. At neutral pH beta-tryptase tetramers in the absence of heparin or dextran sulfate spontaneously convert to inactive monomers. Addition of a polyanion to these monomers at neutral pH fails to convert them back to a tetramer or to an enzymatically active state. In contrast, at acidic pH addition of a polyanion resurrects enzyme activity. Whether this activity is associated with tetramers or monomers depends on the concentration of beta-tryptase. Under the experimental conditions employed at pH 6 in the presence of heparin, the monomer concentration at which 50% conversion to tetramers occurs is 193 ng/mL. Activity against tripeptide substrates by monomers is detected at pH 6 but not at pH 7.4, whereas tetramer activity is greater at pH 7.4 than pH 6.0. Active monomers are inhibited by soybean trypsin inhibitor, bovine pancreatic trypsin inhibitor, antithrombin III, and alpha2-macroglobulin, whereas active tetramers are resistant to these inhibitors. Active monomers form complexes with these inhibitors and cleave both antithrombin III and alpha2-macroglobulin. These inhibitors also prevent reconstitution of monomers to tetramers, indicating that inactive monomers become active monomers before becoming active tetramers. The ability of tryptase monomers to become active at acidic pH raises the possibilities of expanded substrate specificities as well as inhibitor susceptibilities where the low-pH environments associated with inflammation or poor vascularity are encountered in vivo.
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PMID:Human beta-tryptase: detection and characterization of the active monomer and prevention of tetramer reconstitution by protease inhibitors. 1531 37


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