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)

Prostaglandin endoperoxide synthase (PES, EC 1.14.99.1) catalyse the conversion of arachidonic acid into prostaglandin H2. The enzyme is a 140 kDa homodimer which contains both a cyclo-oxygenase activity (converting arachidonate into prostaglandin G2) and peroxidase activity (reducing prostaglandin G2 to H2). PES undergoes rapid self-inactivation during oxygenation of arachidonate to prostaglandin H2 in vitro. The previously reported cDNA-derived amino acid sequence indicates numerous sites for trypsin or thrombin cleavage. Most of these sites must be inaccessible, since these enzymes cleave only at Arg253. The enzyme appears to be a self-adherent and highly folded molecule, since after cleavage it retains its functional assembly and its homodimer size of 140 kDa, as well as its overall enzymic activity. Only under denaturing conditions (e.g. SDS/PAGE) can the proteolytic peptides be demonstrated: a 38 kDa C-terminal fragment containing the aspirin-derived-acetyl-binding ability, and a 33 kDa N-terminal fragment. In the present studies we investigated whether the two enzymic activities of PES can be differentially manipulated by proteolytic cleavage or by substrate (arachidonate) self-inactivation. The results indicated that, during arachidonate oxygenation by PES, the cyclooxygenase activity is selectively inactivated, whereas the peroxidase activity is essentially retained. By contrast, thrombin or trypsin cleavage of pure PES or microsomal PES (to yield the 38 and 33 kDa peptide fragments) inactivated the peroxidase, but not the cyclo-oxygenase. Taken together, these results suggest the presence of separate cyclo-oxygenase and peroxidase structural domains on the enzyme.
...
PMID:Differential modification of cyclo-oxygenase and peroxidase activities of prostaglandin endoperoxidase synthase by proteolytic digestion and hydroperoxides. 211 18

The specificity by which Haemophilus species acquired iron from transferrin (TF) was investigated. In a plate bioassay H. influenzae used iron bound to human, bovine and rabbit TFs but not mouse, rat, dog, horse, guinea-pig, pig or ovo- TFs or human and bovine lactoferrins. In contrast, H. pleuropneumoniae used iron only from pig TF whilst H. parainfluenzae was unable to utilize iron bound to any of the human or animal TFs tested. The inhibition of growth imposed on H. influenzae type b strain Eagan by the addition of the synthetic iron chelator EDDA to the culture medium was reversed by 30% iron-saturated human TF added directly to the medium but not when the TF was contained inside a dialysis bag. Dot-blotting of whole cells revealed that human TF bound to the surface of bacteria cultured in iron-restricted but not in iron-plentiful media. Incubation of whole bacterial cells in the presence of the proteolytic enzyme trypsin also abolished TF-binding activity, suggesting that the TF receptor was a protein. In competition dot blotting experiments, human and bovine but not rabbit, dog, mouse or guinea-pig TFs blocked the binding of a horseradish peroxidase--human TF conjugate. SDS-PAGE and Western blotting of outer membranes revealed the presence of a TF-binding protein of approximately 72 kDa. These results suggest that the acquisition of TF-bound iron by H. influenzae type b probably involves a direct interaction with an outer-membrane protein which shows some TF-species specificity.
...
PMID:Siderophore-independent acquisition of transferrin-bound iron by Haemophilus influenzae type b. 214 16

The purpose of this study was to determine the distribution of mucin glycoprotein 1 (MG1) within submandibular, parotid, labial and palatine salivary tissues. Formalin-fixed and frozen tissue sections were examined histochemically with PAS, Alcian blue and Meyer's mucicarmine, and immunocytochemically with an anti-mucin glycoprotein 1 monoclonal antibody (clone 3/E8). Clone 3/E8 was produced in Balb/c mice using mucin-enriched chromatographic fractions from submandibular-sublingual saliva. The monospecificity of 3/E8 was confirmed by immuno-dot blotting and SDS-PAGE/electrophoretic transfer. Clone 3/E8 (IgG1; kappa) was of moderate affinity, and was directed to a carbohydrate-containing, TPCK-trypsin-insensitive and pronase-insensitive epitope on this mucin, which was not blood-group specific. The location of mucin glycoprotein 1 was determined by both indirect (peroxidase-antiperoxidase) and direct methods. Mucin glycoprotein 1 was localized within all labial acini examined, but was not found within parotid tissues. Histochemical methods stained all submandibular, palatine and labial acini, but immunocytochemistry with monoclonal antibody revealed heterogeneous staining with clone 3/E8 in submandibular and palatine tissues. These findings suggest the presence of mucin glycoprotein 1-specific acinar cell subpopulations within human submandibular and palatine salivary tissues.
...
PMID:Immunochemistry of high molecular-weight human salivary mucin. 218 37

Dot blot analysis on enzymatically amplified trophoblast DNA with allele specific oligonucleotide probes is currently used for the prenatal diagnosis of single gene disorders characterised at the molecular level, such as the beta thalassaemias, phenylketonuria, sickle cell anaemia, and alpha 1-anti-trypsin deficiency. A potential problem with the use of this procedure is the co-amplification of maternal sequences, which may obscure the diagnosis in the fetus. To address this question, we carried out prenatal diagnosis of beta thalassaemia in 300 couples at risk by dot blot analysis on enzymatically amplified DNA with 32P or horseradish peroxidase labelled allele specific oligonucleotide probes. We verified the diagnosis obtained by this procedure with oligonucleotide hybridisation on electrophoretically separated non-amplified trophoblast DNA fragments. We detected no co-amplified maternal sequences, even with a faint signal, in the dot blot of trophoblast DNA from those fetuses diagnosed as normal or homozygotes, nor in those diagnosed as heterozygotes, who were born to parents carrying different mutations and had inherited the paternal mutation. These results indicate that, when careful dissection of trophoblast tissue from maternal decidua is carried out, amplification of chorionic villi DNA is not associated with amplification of maternal DNA sequences. We may thus conclude that dot blot analysis of trophoblast DNA is a very reliable procedure for prenatal diagnosis.
...
PMID:Reliability of prenatal diagnosis of genetic diseases by analysis of amplified trophoblast DNA. 232 4

A rapid neutralization test for influenza A and B viruses was developed. In this method, a 96-well tissue culture plate was used for the preparation of cell monolayers and the peroxidase-antiperoxidase staining technique was used for the visualization of foci infected with these viruses. In the presence of trypsin and tragacanth gum, clear foci developed 1 day after infection. A linear relationship between virus dilutions and numbers of foci was observed. When neutralizing antibodies in some test sera were assayed, a good correlation was observed between the titers obtained by the focus method and those obtained by the ordinary plaque method. In addition, many serum specimens were investigated by the neutralization test, and it was demonstrated that the test is useful for serological studies of influenza.
...
PMID:Rapid focus reduction neutralization test of influenza A and B viruses in microtiter system. 238 Mar 59

Paraffin sections of formaldehyde-fixed renal biopsies were labeled for complement C3 by a polyclonal rabbit antibody to human complement C3, by the peroxidase-antiperoxidase complex (PAP) and the avidin-biotin peroxidase complex (ABC) techniques, respectively. All tissues had C3 deposits according to direct immunofluorescence on fresh frozen sections. Staining for muramidase was introduced as an intrinsic control for the degree of tissue proteolysis after the necessary trypsin digestion prior to the immunoenzyme labeling. The results indicated that even minute deposits of C3 could be detected in paraffin sections by the ABC method, which was more sensitive than the PAP technique; the ABC method allowed a maximal dilution of 1:2,400 of the primary antibody as compared to 1:800 for the PAP technique.
...
PMID:Conditions for the immunohistochemical demonstration of complement factor C3 in formaldehyde-fixed and paraffin-embedded renal tissues. 242 Jul 64

The effect of three proteases--trypsin, pepsin, and pronase--on the immunohistochemical staining of keratins with a broad-spectrum monoclonal antibody was investigated in paraffin sections of formalin and ethanol-fixed tissues by means of the peroxidase-antiperoxidase method. Both the length of exposure to the fixative and the duration of proteolysis were varied over a wide range. Ethanol-fixed tissues showed excellent preservation of the antigenicity of keratins, and no appreciable differences in immunostaining related to the length of fixation were found. The use of proteolytic enzymes did not improve these results; on the contrary, it caused rapid tissue disintegration. Formalin-fixed epithelial tissues stained weakly or failed to stain unless they were treated with a proteolytic enzyme. The optimal length of proteolysis varied with the degree of fixation; tissues that were fixed for long periods of time in formalin required longer exposure to a proteolytic enzyme and were more resistant to digestion than were tissues that were fixed briefly. No significant advantage of one protease over another was found in this study. We conclude that a proteolytic step must precede immunostaining for keratins if the tissue is fixed in formalin, but that the digestion period must be adjusted according to the length of exposure to the fixative. The superiority of alcohol over formalin fixation for the preservation of the antigenicity of keratins is confirmed by this study.
...
PMID:The influence of protease digestion and duration of fixation on the immunostaining of keratins. A comparison of formalin and ethanol fixation. 242 35

Recent studies indicate that intramammary lymphatic invasion represents an important prognostic parameter in breast carcinomas. However, the identification of intramammary lymphatic invasion in tissue sections is a subjective procedure, frequently hampered by factors such as fixation artefacts and interobserver variations. In this study, monoclonal antibodies to ABH isoantigens were applied on formalin-fixed, paraffin-embedded breast carcinoma tissue by using the avidin-biotin-peroxidase complex technique. In addition, the H antigen was localized using the Ulex europeus agglutinin I lectin binding technique. Isoantigen localization provided excellent delineation of lymphatics and blood vessels, in general unhampered by the retention of isoantigen expression in some breast carcinomas. In comparison, Factor VIII-related antigen localization required prior trypsin enhancement and was less sensitive and less consistent. The staining for isoantigens was more intense in vascular than in lymphatic endothelium. ABH isoantigen localization of lymphatic channels identified lymphatic tumor emboli peripheral to and within the carcinomas, and distinguished bona fide intramammary lymphatic invasion from tissue shrinkage artefacts. The applicability to routinely processed tissue permits retrospective studies and renders the identification of intramammary lymphatic invasion a more objective procedure. Further studies are needed to assess the role of this technique in evaluating the prognostic value of intramammary lymphatic invasion; the technique may be extended also to the study of other neoplasms.
...
PMID:Intramammary lymphatic invasion in breast carcinomas. Evaluation using ABH isoantigens as endothelial markers. 242 60

The effects of proteases on air-space clearance (AC) of small ([14C]sucrose, 342 daltons) and large (125I-neutral dextran, 70,000 daltons) solutes were studied in isolated, fluid-filled hamster lungs that were perfused in a nonrecirculating system. When instilled into the air spaces, porcine pancreatic elastase (0.1-0.4 mg/ml) and bovine pancreatic trypsin (BPT) (0.5-2.0 mg/ml), but neither Clostridium histolyticum collagenase (5.0 mg/ml) nor phenylmethylsulfonyl fluoride-inactivated BPT caused large increases in the AC of both tracer molecules. BPT-induced solute clearance was further characterized functionally and morphologically. The functional characteristics of solute AC under steady-state conditions did not indicate that transepithelial transport was diffusion-limited. Inhibition by millimolar concentrations of Zn2+ and by lung cooling, along with electron microscopic studies employing horseradish peroxidase as a macromolecule tracer, were consistent with epithelial solute transport by a vesicular mechanism (transcytosis). Solute transport from the interstitial compartment to the lung exterior was shown to occur via two pathways. By unknown mechanisms BPT caused small amounts of water to flow through an incompletely identified, extravascular pathway. In BPT-exposed lungs efflux of 125I-dextran 70 occurred almost exclusively through this pathway, whereas [14C]sucrose was transported to the lung exterior partly through this same pathway and partly through the vasculature. The large differences in the diffusion coefficients of the two tracers may have accounted for these observed patterns of solute efflux from the lung. The possible significance of our findings to the pathogenesis of experimental emphysema are discussed.
...
PMID:Effect of proteolytic enzymes on transepithelial solute transport. 243 Sep 29

This is the third report in a series on the inflammatory mediators and modulators released in organ culture from skin lesions of various ages, which were produced in vivo in rabbits by the military vesicant, sulfur mustard (SM). It describes the electrophoretic protein fractions and trypsin-inhibitory capacities of the various culture fluids and the amounts of alpha 1-proteinase inhibitor and alpha-macroglobulin proteinase inhibitors in these fluids. With one-dimensional electrophoresis, the albumin and beta-globulin fractions of protein in culture fluids varied little with the development and healing of the SM lesions. These fractions proportionally resembled the corresponding fractions found in serum. The alpha 1-globulin fraction was proportionally smaller than the corresponding fractions of serum as the lesions healed. The alpha 2-globulin fraction was proportionally smaller than the corresponding fractions of serum at all stages of lesion development and healing. The gamma-globulin fraction was proportionally larger as the lesions healed. With two-dimensional electrophoresis, about 68%, 46%, and 35% of the protein spots in culture fluids from representative 1-day and 6-day SM lesions and normal skin, respectively, matched those from serum. In each case, the large, diffuse, serum albumin spot represented about two-thirds of the protein present. Thus, gravimetrically, in normal skin and in both developing and healing lesions, the extracellular proteins were 80-90% of serum origin. The trypsin-inhibitory capacity (TIC) per milligram protein in the culture fluids of healing lesions was markedly less than the TIC per milligram protein in the fluids of peak lesions. This decrease correlates well with the decrease found in the alpha 1-globulin fraction, which contains alpha 1-antiproteinase (alpha 1-PI) (and alpha 1-macroglobulin [alpha 1M] in rabbits). The alpha 1PI and the alpha 1M-alpha 2M proteinase inhibitors were identified in the culture fluids by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blots, specific antibodies, and the immuno-peroxidase technique. The levels of both free and proteinase-complexed alpha 1PI and alpha M inhibitors in the culture fluids decreased as the lesions healed. In both developing and healing lesions, at least half of the alpha 1PI and alpha M inhibitors seemed to be complexed with proteinases. Thus, serum seems to be a major source of unbounded extracellular protein within acute inflammatory lesions, and serum proteinase inhibitors seem to be the host's major defense against local damage by proteinases from serum, infiltrating leukocytes, and activated fibroblasts.
...
PMID:Inflammatory mediators and modulators released in organ culture from rabbit skin lesions produced in vivo by sulfur mustard. III. Electrophoretic protein fractions, trypsin-inhibitory capacity, alpha 1-proteinase inhibitor, and alpha 1- and alpha 2-macroglobulin proteinase inhibitors of culture fluids and serum. 243 44


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---