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

---

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

A spontaneous mammary adenocarcinoma (AC) from an inbred female rat was investigated with regard to secretion of neutral proteases. Cultures of neoplastic epithelial cells derived from the tumour secreted an enzyme that fulfilled the criteria for a specific collagenase. In contrast to cultures of non-neoplastic cells, tumour collagenase was present as an active enzyme, since treatment with trypsin or p-aminophenylmercuric acetate (APMA) did not increase activity. The neoplastic cells were also prolific producers of plasminogen activator (PA). Dexamethasone (Dex) (10(-6)M) markedly reduced the levels of both enzymes. Addition of tranexamic acid (TA), an inhibitor of plasmin and of plasminogen activation, did not affect collagenase activity, even at 10(-1)M TA, nor did latent collagenase accumulate. Latent collagenase was secreted in culture by normal fibroblasts from neonatal rat lungs. This latent enzyme was activated by the addition of tumour cell medium plus plasminogen, but this effect was inhibited by the addition of TA. These results demonstrate that the neoplastic cells themselves secrete collagenase as an active enzyme. PA is also secreted, is not involved with tumour collagenase, but is capable, in the presence of plasminogen, of activating latent collagenase produced by the non-neoplastic cells within the tumour or in the surrounding tissue. This tumour possesses potent collagenolytic ability in vitro which may be partly responsible for its rapid invasion in vivo.
...
PMID:Rat mammary carcinoma cells secrete active collagenase and activate latent enzyme in the stroma via plasminogen activator. 627 36

ACTH activity in glacial acetic acid extracts of normal rat tissues was studied by both ACTH RIA and a sensitive in vitro bioassay. ACTH immunoactivity was found in all tissues: brain, 278 +/- 54 (mean +/- SE; picograms per mg protein); stomach, 59 +/- 4; kidney, 47 +/- 3; colon, 40 +/- 4; small intestine, 37 +/- 4; liver, 18 +/- 2; and heart, 16 +/- 3. Tissue ACTH showed parallelism with ACTH standard in the RIA. No correlation existed between tissue ACTH and plasma ACTH in normal rats. Dexamethasone treatment (0.4 mg/day for 5 days) suppressed plasma ACTH, but did not affect tissue ACTH levels. When tissue extracts were passed through Sephadex G-75-SF columns, ACTH immunoactivity was exclusively eluted in the portion of bigger molecular weight than ACTH standard, except in the brain. Based on this column chromatography, the molecular weight of the main peak of activity was estimated as 26,000. Tissue ACTH-like material contained no detectable biological activity (less than 2 pg/100 ng tissue). However, biological activity was easily detectable after exposure of the tissue extracts to trypsin. When studied by immunoassay and bioassay, this 26,000 mol wt ACTH was digested and cleaved to 4,500 mol wt and biologically active ACTH with trypsin treatment. Tissue ACTH immunoactivity does not seem to be the result of artifacts: 1) extracts were adjusted to pH 8.0 and a common osmolality (150 mosmol/liter) before assay; 2) protein contents in RIA tubes were only 0.1-1.6 mg; 3) tissue extracts incubated with [125I]iodo-ACTH for 48 h produced less than 5% damage of labeled hormone, as assessed by moderate excess of antibody binding; 4) enzyme inhibitors did not modify tissue ACTH levels; and 5) ACTH immunoactivity of tissue extracts was absorbed by anti-ACTH immunocolumns. We conclude that high molecular weight ACTH-like materials are widespread in normal rat extrapituitary tissues and are probably a precursor form of 4500 mol wt ACTH.
...
PMID:Widespread presence of large molecular weight adrenocorticotropin-like substances in normal rat extrapituitary tissues. 630 59

[3H]Dexamethasone 21-mesylate affinity-labeled glucocorticoid receptors were subjected to controlled proteolysis by trypsin, chymotrypsin, and Staphylococcus aureus V8 protease and then analyzed on denaturing constant percentage or gradient polyacrylamide gels. The molecular weights (Mr congruent to 98 000) and cleavage patterns for rat liver and HTC cell receptors indicated extensive homology between the glucocorticoid receptors from normal rat liver and a transformed rat liver cell line. The major DNA-binding species generated by chymotrypsin treatment was found to be a 42K fragment that was accompanied by several unresolved, slightly lower molecular weight fragments. The meroreceptors obtained after trypsinization were comprised of two species of Mr 30 000 and 28 000. Each of the three proteases, despite their differing specificities, generated fragments with molecular weights close to 42 500, 30 500, and 27 000. Nevertheless, each of the three proteases gave rise to a distinctive "ladder" of labeled fragments. No differences could be detected in the digestion patterns of unactivated and activated HTC cell complexes for all three proteases. Also, native and denatured receptor-steroid complexes yielded surprisingly similar digestion patterns with each enzyme. Digestion of denatured complexes readily generated large amounts of a fragment of Mr congruent to 15 000 that was much smaller than the protease-resistant meroreceptors formed from native complexes. The presence of these approximately 15K fragments suggested that the [3H]dexamethasone 21-mesylate labeling of the steroid-binding cavity is restricted to a relatively small segment of the receptor.
...
PMID:Limited proteolysis of covalently labeled glucocorticoid receptors as a probe of receptor structure. 639 42

The glucocorticoid receptor in cytosol from human brain was studied using isoelectric focussing in slabs of polyacrylamide gel. [3H]Dexamethasone was used as tracer for receptor analysis. The glucocorticoid receptor from human brain was compared to the glucocorticoid receptor in rat brain. A similar peak of radioactivity with a pI of about 6.1 was obtained by isoelectric focussing of cytosol from both human brain and rat brain. The trypsin-induced fragmentation patterns of the glucocorticoid receptor from human brain and rat brain were very similar when analyzed by isoelectric focussing. The hormone specificity of the glucocorticoid receptor in human brain and in rat brain cytosol was compared by competition experiments using unlabelled dexamethasone, betamethasone, cortisol and corticosterone as competitors. No difference between human brain and rat brain cytosol was detected. It is concluded that the hormone specificity and the protein structure of the glucocorticoid receptors in human brain and in rat brain are similar.
...
PMID:A qualitative comparison of the glucocorticoid receptor in cytosol from human brain and rat brain. 728 14

Human fetal liver cells cultured in the presence of recombinant human stem cell factor (rhuSCF) give rise to highly purified mast cell populations. This study examined the effect of steroid hormones on mast cell differentiation. Dispersed fetal liver cells cultured in the presence of rhuSCF at 50 ng/ml and in the presence or absence of various steroid hormones for 4 weeks, were analysed for the presence of mast cells by metachromatic staining with toluidine blue, by immunohistochemistry with a monoclonal antibody against tryptase, and by immunofluorescent flow cytometry with a monoclonal antibody against Kit. Dexamethasone added to the cultures at day 0 resulted in a dose-dependent inhibition of rhuSCF-induced mast cell differentiation with > 85% inhibition seen at a dose of 10(-6) M. A similar effect was seen with hydrocortisone, but not with oestradiol or progesterone. The addition of dexamethasone resulted in decreased DNA synthesis in 14-day-old cultured cells, as assessed by incorporation of bromodeoxyuridine. Addition of dexamethasone to 3-week-old SCF-dependent fetal liver mast cells had no significant effect on mast cell survival. Removal of dexamethasone after 3 weeks of culture with SCF did not result in mast cell development. Thus, dexamethasone inhibits SCF-induced development of mast cells from fetal liver cells, but shows no appreciable effect on developed mast cells.
...
PMID:Dexamethasone inhibits the development of mast cells from dispersed human fetal liver cells cultured in the presence of recombinant human stem cell factor. 753 66

Pulp tissue was obtained from maxillary incisors of young adult male Wistar rats, minced and digested with 0.5% trypsin and 0.02% EGTA at 37 degrees C for 30 min. Dissociated cells were cultured with or without 10 nM dexamethasone using Eagle's minimal essential medium supplemented with 10% fetal bovine serum and 50 micrograms/ml ascorbic acid. Confluent cells were subcultured at 7 days and the medium further supplemented with beta-glycerophosphate (beta-GP). Dexamethasone in primary culture and/or secondary culture enhanced the formation of mineralized tissue while > 5 mM beta-GP was necessary for mineralization to occur. Biochemical analysis of the radiolabelled medium revealed that these cells produced type I, type I trimer and type III collagens. Analysis of [32PO4]-labelled medium, using DEAE-Sephacel ion-exchange chromatography and sodium dodecylsulphate-polyacrylamide gel electrophoresis, showed that these cells produced phosphophoryn-like protein. These results indicate that some of the rat dental pulp cells in culture express an odontoblast-like phenotype.
...
PMID:Characterization of a system of mineralized-tissue formation by rat dental pulp cells in culture. 824 85

Amygdalar CRF has been implicated in the mediation of stress behaviors. The signal transduction pathways that regulate amygdalar CRF are not well understood. In this report, we have examined the effect of protein kinase A and C activators, dexamethasone, and interleukin 6 on CRF messenger RNA (mRNA) and CRF peptide expression in dissociated amygdalar cultures. The amygdala from E19 rat pups was dissected out bilaterally and dissociated in 0.25% trypsin for 10-15 min and plated. On day 17 in culture, CRF mRNA and peptide were measured following treatment with the following agents: forskolin, the phorbol ester-phorbol 12 myristate 13-acetate (TPA), dexamethasone, and interleukin-6 (IL6). Both forskolin and IL6, but not TPA, increased CRF mRNA in a time- and dose-dependent manner. Secretion and intracellular content of the CRF peptide also increased with both forskolin and IL6 treatment but not with TPA. Dexamethasone treatment did not alter the expression of CRF message or peptide. Transfection of the primary cultures with a rat CRF promoter-luciferase reporter construct followed by treatment with all four agents produced alterations in luciferase expression that were consistent with changes observed at the level of CRF mRNA and peptide. The results suggest that CRF regulation in the amygdala differs from that known to occur in the hypothalamus, and that elevation of IL6 levels within the central nervous system may directly act to stimulate CRF production and secretion from limbic structures such as the amygdala, to promote subsequent behavioral changes.
...
PMID:Regulation of corticotropin-releasing factor (CRF) messenger ribonucleic acid and CRF peptide in the amygdala: studies in primary amygdalar cultures. 934 5

Glucocorticoid-sensitive alkaline proteases are localized in the nuclear and mitochondrial fractions of rat thymocytes. Dexamethasone load increased alkaline protease activity in the nuclear fraction and decreased or even eliminated it in the mitochondrial fraction. The inhibitory analysis showed that SH groups and disulfide bonds play a crucial role in the functioning of glucocorticoid-activated nuclear alkaline protease. Hence, this enzyme can be assigned to as cysteine proteases. Mitochondrial alkaline protease is a serine hydrolase, although it does not belong to the class of trypsin- or chymotrypsin-like enzymes. The role of alkaline proteases in apoptotic death of thymocytes is discussed.
...
PMID:Mitochondrial and nuclear glucocorticoid-sensitive alkaline proteases in thymocytes. 1168 37

Pleural inflammation underlies many pleural diseases, but its pathogenesis remains unclear. Proteinase-activated receptor-2 (PAR(2)) is a novel seven-transmembrane receptor with immunoregulatory roles. We hypothesized that PAR(2) is present on mesothelial cells and can induce pleural inflammation. PAR(2) was detected by immunohistochemistry in all (19 parietal and 11 visceral) human pleural biopsies examined. In cultured murine mesothelial cells, a specific PAR(2)-activating peptide (SLIGRL-NH(2)) at 10, 100, and 1,000 muM stimulated a 3-, 42-, and 1,330-fold increase of macrophage inflammatory protein (MIP)-2 release relative to medium control, respectively (P < 0.05 all) and a 2-, 32-, and 75-fold rise over the control peptide (LSIGRL-NH(2), P < 0.05 all). A similar pattern was seen for TNF-alpha release. Known physiological activators of PAR(2), tryptase, trypsin, and coagulation factor Xa, also stimulated dose-dependent MIP-2 release from mesothelial cells in vitro. Dexamethasone inhibited the PAR(2)-mediated MIP-2 release in a dose-dependent manner. In vivo, pleural fluid MIP-2 levels in C57BL/6 mice injected intrapleurally with SLIGRL-NH(2) (10 mg/kg) were significantly higher than in mice injected with LSIGRL-NH(2) or PBS (2,710 +/- 165 vs. 880 +/- 357 vs. 88 +/- 46 pg/ml, respectively; P < 0.001). Pleural fluid neutrophil counts were higher in SLIGRL-NH(2) group than in the LSIGRL-NH(2) and PBS groups (by 40- and 26-fold, respectively; P < 0.05). This study establishes that activation of mesothelial cell PAR(2) potently induces the release of inflammatory cytokines in vitro and neutrophil recruitment into the pleural cavity in vivo.
...
PMID:Activation of proteinase-activated receptor-2 in mesothelial cells induces pleural inflammation. 1559 15

The epithelial Na(+) channel (ENaC) that mediates regulated Na(+) reabsorption by epithelial cells in the kidney and lungs can be activated by endogenous proteases such as channel activating protease 1 and exogenous proteases such as trypsin and neutrophil elastase (NE). The mechanism by which exogenous proteases activate the channel is unknown. To test the hypothesis that residues on ENaC mediate protease-dependent channel activation wild-type and mutant ENaC were stably expressed in the FRT epithelial cell line using a tripromoter human ENaC construct, and protease-induced short-circuit current activation was measured in aprotinin-treated cells. The amiloride-sensitive short circuit current (I(Na)) was stimulated by aldosterone (1.5-fold) and dexamethasone (8-fold). Dexamethasone-treated cells were used for all subsequent studies. The serum protease inhibitor aprotinin decreased baseline I(Na) by approximately 50% and I(Na) could be restored to baseline control values by the exogenous addition of trypsin, NE, and porcine pancreatic elastase (PE) but not by thrombin. All protease experiments were thus performed after exposure to aprotinin. Because NE recognition of substrates occurs with a preference for binding valines at the active site, several valines in the extracellular loops of alpha and gamma ENaC were sequentially substituted with glycines. This scan yielded two valine residues in gamma ENaC at positions 182 and 193 that resulted in inhibited responses to NE when simultaneously changed to other amino acids. The mutations resulted in decreased rates of activation and decreased activated steady-state current levels. There was an approximately 20-fold difference in activation efficiency of NE against wild-type ENaC compared to a mutant with glycine substitutions at positions 182 and 193. However, the mutants remain susceptible to activation by trypsin and the related elastase, PE. Alanine is the preferred P(1) position residue for PE and substitution of alanine 190 in the gamma subunit eliminated I(Na) activation by PE. Further, substitution with a novel thrombin consensus sequence (LVPRG) beginning at residue 186 in the gamma subunit (gamma(Th)) allowed for I(Na) activation by thrombin, whereas wild-type ENaC was unresponsive. MALDI-TOF mass spectrometric evaluation of proteolytic digests of a 23-mer peptide encompassing the identified residues (T(176)-S(198)) showed that hydrolysis occurred between residues V193 and M194 for NE and between A190 and S191 for PE. In vitro translation studies demonstrated thrombin cleaved the gamma(Th) but not the wild-type gamma subunit. These results demonstrate that gamma subunit valines 182 and 193 are critical for channel activation by NE, alanine 190 is critical for channel activation by PE, and that channel activation can be achieved by inserting a novel thrombin consensus sequence. These results support the conclusion that protease binding and perhaps cleavage of the gamma subunit results in ENaC activation.
...
PMID:A segment of gamma ENaC mediates elastase activation of Na+ transport. 1799 93


<< Previous 1 2 3 Next >>

---