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)

We have investigated the effects of some factors suspected of inducing spuriously increased tryptase concentrations, specifically sampling site, conjunctival petechial bleeding and prone position at the time of death as indicators of premortem asphyxia, and resuscitation efforts by external cardiac massage. Tryptase was measured in blood from the femoral vein in 60 deaths: 39 control cases who died rapidly (within minutes) from natural causes (sudden cardiac death and acute aortic dissection), 16 with death caused by prolonged asphyxia (traumatic compression of the chest and suffocation due to body position or smothering), and five anaphylactic deaths. In 44 of these cases, tryptase was measured in both heart and femoral blood. Mast cell tryptase was analyzed with a commercial FEIA method (Pharmacia Diagnostics AB, Uppsala, Sweden) measuring both alpha- and beta-tryptase. Assuming that tryptase values in the control group were gamma distributed, we calculated the upper normal limits for tryptase concentrations in femoral blood. It was found that 95% of the controls had values below 44.3 mug/l (femoral blood), SD 5.27 mug/l. All but one of the anaphylactic deaths had tryptase concentrations exceeding that limit. Tryptase was significantly elevated in femoral blood from anaphylactic deaths (p<0.007), compared with the controls. Also, in the cases where death had occurred due to asphyxia tryptase was elevated in femoral blood (p<0.04). A significant difference in tryptase concentrations was seen between blood from the heart and the femoral vessels (p<0.02) in the whole material (n=44). Tryptase concentrations in femoral blood were not influenced by prone position at death, or resuscitation efforts. It is concluded that asphyxia premortem seems to affect tryptase concentrations, that postmortem tryptase measurements should be done in serum from femoral blood, and that the normal upper limit, covering 95%, is 44.3 microg/l.
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PMID:Mast cell tryptase in postmortem serum-reference values and confounders. 1671 Jul 35

A series of novel alpha-keto-[1,2,4]-oxadiazoles has been synthesized as human tryptase inhibitors for evaluation as a new class of anti-asthmatic agent. The inhibitor design is focused on using a prime-side hydrophobic pocket and the S2 pocket of beta-tryptase to achieve inhibition potency and selectivity over other serine proteases.
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PMID:Design of novel, potent, and selective human beta-tryptase inhibitors based on alpha-keto-[1,2,4]-oxadiazoles. 1671 9

A number of autocrine and paracrine growth regulators are considered to be involved in the survival and proliferation of blast cells in acute myeloid leukemia (AML). We have recently shown that blast cells in a group of patients with AML produce and secrete the mitogenic enzyme tryptase. In the present study, we examined functional effects of tryptase in the context of AML. As assessed by 3H-thymidine uptake experiments, tryptase-containing serum from patients with AML as well as heparin-complexed recombinant tryptase were found to promote the proliferation of cultured bone marrow- and lung fibroblasts in a dose-dependent manner. A neutralizing antibody against human beta-tryptase was found to diminish these growth-stimulatory effects of serum-tryptase in all patients examined. Tryptase also induced the expression of mRNA for GM-CSF and SCF, two cytokines known to promote growth of AML cells, in cultured bone marrow fibroblasts. Neither recombinant tryptase nor tryptase-rich serum of AML patients, showed an effect on the growth of leukemic blast cells irrespective of the FAB category or expression of protease-activated receptor (PAR)-2, a putative molecular target of tryptase. Together, tryptase is secreted from AML blasts as a biologically active molecule that may exhibit paracrine rather than autocrine effects in AML.
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PMID:Evaluation of biologic activity of tryptase secreted from blast cells in acute myeloid leukemia. 1675 62

Tryptases are trypsin-like serine proteases whose expression is restricted to cells of hematopoietic origin, notably mast cells. gamma-Tryptase, a recently described member of the family also known as transmembrane tryptase (TMT), is a membrane-bound serine protease found in the secretory granules or on the surface of degranulated mast cells. The 321 amino acid protein contains an 18 amino acid propeptide linked to the catalytic domain (cd), followed by a single-span transmembrane domain. gamma-Tryptase is distinguished from other human mast cell tryptases by the presence of two unique cysteine residues, Cys(26) and Cys(145), that are predicted to form an intra-molecular disulfide bond linking the propeptide to the catalytic domain to form the mature, membrane-anchored two-chain enzyme. We expressed gamma-tryptase as either a soluble, single-chain enzyme with a C-terminal His tag (cd gamma-tryptase) or as a soluble pseudozymogen activated by enterokinase cleavage to form a two-chain protein with an N-terminal His tag (tc gamma-tryptase). Both recombinant proteins were expressed at high levels in Pichia pastoris and purified by affinity chromatography. The two forms of gamma-tryptase exhibit comparable kinetic parameters, indicating the propeptide does not contribute significantly to the substrate affinity or activity of the protease. Substrate and inhibitor library screening indicate that gamma-tryptase possesses a substrate preference and inhibitor profile distinct from that of beta-tryptase. Although the role of gamma-tryptase in mast cell function is unknown, our results suggest that it is likely to be distinct from that of beta-tryptase.
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PMID:Expression and characterization of recombinant gamma-tryptase. 1681 34

Tryptases comprise a group of trypsin-like serine proteases that are highly and selectively expressed in mast cells and to a lesser extent in basophils. Among them interest has been focused on tryptase beta, primarily because it was the first tryptase identified and because it is the predominant protease and protein component of mast cells. Subsequent studies have provided convincing evidence that tryptase beta is not only a clinically useful marker of mast cells and their activation but that it contributes to the pathogenesis of allergic inflammatory disorders, most notably asthma. The pathogenetic relevance together with the apparent lack of overt physiological functions has caused considerable interest in beta-tryptase as a potential therapeutic target. Meanwhile diverse tryptase inhibitors have been synthesized whose design in part was fostered by the structural analysis of the enzymatically active beta tryptase tetramer. Various compounds have been studied both in animal models and in man, providing proof of principle that tryptase inhibitors have therapeutic potential in asthma. Here we review the rationale to develop tryptase inhibitors and the approaches pursued, and also try to pinpoint some of the problems that hamper the development of clinically applicable drugs.
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PMID:Mast cell tryptase beta as a target in allergic inflammation: an evolving story. 1731 63

TdPI, a tick salivary gland product related to Kunitz/BPTI proteins is a potent inhibitor of human beta-tryptase. Kinetic assays suggest that three of the four catalytic sites of tryptase are blocked by TdPI, and that the inhibition of one of these involves a peptide flanking the Kunitz head. In the course of the inhibition, tryptase cleaves TdPI at several positions. Crystal structures of the TdPI head, on its own and in complex with trypsin, reveal features that are not found in classical Kunitz/BPTI proteins and suggest the mode of interaction with tryptase. The loop of TdPI connecting the beta-sheet with the C-terminal alpha-helix is shortened, the disulphide-bridge pattern altered and N and C termini separated to produce a highly pointed molecule capable of penetrating the cramped active sites of tryptase. TdPI accumulates in the cytosolic granules of mast cells, presumably suppressing inflammation in the host animal's skin by tryptase inhibition.
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PMID:A tick protein with a modified Kunitz fold inhibits human tryptase. 1739 95

Approximately 50% of the weight of a mature mast cell (MC) consists of varied neutral proteases stored in the cell's secretory granules ionically bound to serglycin proteoglycans that contain heparin and/or chondroitin sulfate E/diB chains. Mouse MCs express the exopeptidase carboxypeptidase A3 and at least 15 serine proteases [designated as mouse MC protease (mMCP) 1-11, transmembrane tryptase/tryptase gamma/protease serine member S (Prss) 31, cathepsin G, granzyme B, and neuropsin/Prss19]. mMCP-6, mMCP-7, mMCP-11/Prss34, and Prss31 are the four members of the chromosome 17A3.3 family of tryptases that are preferentially expressed in MCs. One of the challenges ahead is to understand why MCs express so many different protease-proteoglycan macromolecular complexes. MC-like cells that contain tryptase-heparin complexes in their secretory granules have been identified in the Ciona intestinalis and Styela plicata urochordates that appeared approximately 500 million years ago. Because sea squirts lack B cells and T cells, it is likely that MCs and their tryptase-proteoglycan granule mediators initially appeared in lower organisms as part of their innate immune system. The conservation of MCs throughout evolution suggests that some of these protease-proteoglycan complexes are essential to our survival. In support of this conclusion, no human has been identified that lacks MCs. Moreover, transgenic mice lacking the beta-tryptase mMCP-6 are unable to combat a Klebsiella pneumoniae infection effectively. Here we summarize the nature and function of some of the tryptase-serglycin proteoglycan complexes found in mouse and human MCs.
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PMID:Protease-proteoglycan complexes of mouse and human mast cells and importance of their beta-tryptase-heparin complexes in inflammation and innate immunity. 1749 58

Risk assessment of individuals with anaphylaxis is currently hampered by lack of (1) an optimal and readily available laboratory test to confirm the clinical diagnosis of an anaphylaxis episode and (2) an optimal method of distinguishing allergen-sensitized individuals who are clinically tolerant from those at risk for anaphylaxis episodes after exposure to the relevant allergen. Our objectives were to review the effector mechanisms involved in the pathophysiology of anaphylaxis; to explore the possibility of developing an optimal laboratory test to confirm the diagnosis of an anaphylaxis episode, and the possibility of improving methods to distinguish allergen sensitization from clinical reactivity; and to develop a research agenda for risk assessment in anaphylaxis. Researchers from the American Academy of Allergy, Asthma & Immunology and the European Academy of Allergology and Clinical Immunology held a PRACTALL (Practical Allergy) meeting to discuss these objectives. New approaches being investigated to support the clinical diagnosis of anaphylaxis include serial measurements of total tryptase in serum during an anaphylaxis episode, and measurement of baseline total tryptase levels after the episode. Greater availability of the test for mature beta-tryptase, a more specific mast cell activation marker for anaphylaxis than total tryptase, is needed. Measurement of chymase, mast cell carboxypeptidase A3, platelet-activating factor, and other mast cell products may prove to be useful. Consideration should be given to measuring a panel of mediators from mast cells and basophils. New approaches being investigated to help distinguish sensitized individuals at minimum or no risk from those at increased risk of developing anaphylaxis include measurement of the ratio of allergen-specific IgE to total IgE, determination of IgE directed at specific allergenic epitopes, measurement of basophil activation markers by using flow cytometry, and assessment of allergen-specific cytokine responses. Algorithms have been developed for risk assessment of individuals with anaphylaxis, along with a research agenda for studies that could lead to an improved ability to confirm the clinical diagnosis of anaphylaxis and to identify allergen-sensitized individuals who are at increased risk of anaphylaxis.
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PMID:Risk assessment in anaphylaxis: current and future approaches. 1760 45

Leech-derived tryptase inhibitor (LDTI), comprising 46 residues and a fold stabilized by three disulfide bonds, is the only protein known to inhibit human beta-tryptase with high affinity. The present work examines its oxidative folding and reductive unfolding with chromatographic and disulfide analysis of the trapped intermediates. LDTI folds and unfolds through a sequential oxidation of its cysteine residues that give rise to the accumulation of a few one- and two-disulfide intermediates. Three species containing two native disulfide bonds (IIa, IIb, and IIc) are detected in LDTI folding, but only one (IIb) seems to be productive and oxidizes into the native structure. Stop/go experiments indicate that the intermediates IIa and IIc must reduce or rearrange their disulfide bonds to reach the productive route. The acquisition of the native structure is extremely fast and efficient, probably influenced by the low levels of non-native three-disulfide (scrambled) isomers occurring along the reaction. Finally, the Cys14-Cys40 disulfide bond, buried in native LDTI and formed in IIa and IIb intermediates, appears to be a key factor for both the initiation of folding and the stability of this molecule. Together, the derived data provide a molecular basis for development of new LDTI variants with altered properties.
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PMID:Oxidative folding of leech-derived tryptase inhibitor via native disulfide-bonded intermediates. 1800 73

Tryptase is the most abundant protease in human mast cells, and is often used as a marker for the enumeration of mast cells in tissue. Here we report that tumour cells from Hodgkin lymphoma, the so called Hodgkin and Reed-Sternberg cells, can express tryptase. Hodgkin lymphoma cell lines expressed mRNA for both alpha- and beta-tryptase and also produced the protein, although at much lower concentrations than mast cells. However, the frequency of tryptase positive HRS-cells in situ was very low. This report demonstrates that tumour cells of lymphoid origin can express tryptase in vitro and in situ.
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PMID:Expression of mast cell tryptases in Hodgkin and Reed-Sternberg (HRS) cells. 1802 Nov 88


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