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)

Serum immunoreactive trypsin (SIT) concentrations were measured in 244 patients with infectious illnesses and in 281 children with diabetes of recent onset. Results were compared with reference ranges established in 107 patients with non-infectious, non-diabetic illnesses, in whom SIT concentrations were found to increase with advancing age. Reduced or undetectable concentrations of SIT were associated with diabetes in children and with a few cases of severe childhood infection. Increased SIT concentrations were associated with virologically confirmed cases of infection with mumps and Coxsackie B virus infection, and with clinical diagnoses of mumps, PUO, and meningitis in children, and with Bornholm disease, cardiac infection, and respiratory infection in adults. It is suggested that silent invasion of the exocrine pancreas with elevation of the SIT concentration may accompany infection by Coxsackie B, mumps, and, possibly, other viruses.
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PMID:Serum immunoreactive trypsin concentrations in infectious and non-infectious illnesses and in juvenile diabetes. 51 51

Interferon levels in nasal secretions of infants under one year of age, and hospitalized with lower repiratory tract disease, were measured during two respiratory infection seasons. In the first year serial secretions from 50 infants with respiratory syncytial virus infection were examined. Undetectable or low levels of interferon were found in all samples, and mean levels did not fluctuate significantly in relation to disease and recovery. This was in contrast to anti-RSV IgA, which appeared and increased in concentration as virus shedding decreased and stopped. In the second year secretions were obtained from nine infants with influenza A virus infection as well as from 13 with RSV. All those with influenza developed measurable interferon in secretions (geometric mean titer 138 units/ml), which was acid and heat stable, and trypsin sensitive (type I interferon). RSV infection again stimulated very low levels (geometric mean 5 units/ml). The lack of correlation of interferon concentration with cessation of RSV shedding suggests either that it is not involved in recovery or that low levels are adequate. On the other hand, it appears that the young infant is fully capable of a brisk local interferon response, at least to infection by influenza A.
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PMID:Interferon in nasal secretions from infants with viral respiratory tract infections. 65 Mar 42

For the determination of a species-specific antigen of Streptococcus (S.) equi, acid extracts of group C streptococcal strains from horses (S. equi, S. zooepidemicus, S. equisimilis) were investigated using polyacrylamide gel electrophoresis and the immunoblotting technique. Using sera of horses suffering from strangles as well as sera from horses with respiratory infection of unknown etiology, Western blotting yielded more or less multiple banding reactions with bands in the 70, 54, 42, 40, and 31-28 kd molecular weight ranges against extracts of all of the 3 different bacterial species. However, an antigen found in this study at 18-16 kd which was highly sensitive to trypsin, proved to react specifically and regularly only with the serum of horses exposed to S. equi. The specificity of the reaction was assured by antisera of rabbits and horses vaccinated against S. equi, S. zooepidemicus or S. equisimilis, respectively, and by cross absorption of a serum originating from a mare recovered from strangles with Lancefield group C and group G streptococci as well as a strain of S. pyogenes. According to Western blot results on 180 serum pairs from horses with clinical signs of respiratory infection, 15.6% of which gave positive reactions, the 18-16 kd antigen appears as a marker suitable for qualitative testing of horse sera for antibodies to S. equi.
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PMID:Studies of antigenic components in acid extracts of group C streptococci with special reference to Streptococcus equi. 212 86

A DNA copy of the influenza virus hemagglutinin gene, derived from influenza virus A/Jap/305/57 (H2N2) was inserted into the genome of vaccinia virus under the control of an early vaccinia virus promoter. Tissue culture cells infected with the purified recombinant virus synthesized influenza hemagglutinin, which was glycosylated and transported to the cell surface where it could be cleaved with trypsin into HA1 and HA2 subunits. Rabbits and hamsters inoculated intradermally with recombinant virus produced circulating antibodies that inhibited hemagglutination by influenza virus. Furthermore, vaccinated hamsters achieved levels of antibody similar to those obtained upon primary infection with influenza virus and were protected against respiratory infection with the A/Jap/305/57 influenza virus.
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PMID:Construction and characterization of an infectious vaccinia virus recombinant that expresses the influenza hemagglutinin gene and induces resistance to influenza virus infection in hamsters. 658 Jun 32

Binding domains on rat dopamine transporters for cocaine and 1-(2-diphenylmethoxy)ethyl-4-(3-phenylpropyl)piperazine compounds were identified using controlled proteolysis of photoaffinity-labeled protein and epitope-specific immunoprecipitation of the labeled fragments. Rat dopamine transporters were photoaffinity labeled with 1-[2-(diphenylmethoxy)ethyl]-4-[2-(4-azido- 3-[125I]iodophenyl)ethyl]piperazine ([125I]DEEP) [a 1-(2-di- phenylmethoxy)ethyl-4-(3-phenylpropyl)piperazine analog] or 3 beta-(p-chlorophenyl)tropane-2 beta-carboxylic acid, 4'-azido-3'- [125I]iodophenylethyl ester ([125I]RTI 82) (a cocaine analog) and were gel purified to remove contaminating radioactivity. The resulting samples were treated with V8 protease or trypsin and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The peptide maps generated with each enzyme were different for each of the ligands, suggesting that the ligands were incorporated into different regions of the protein. Identical peptide maps were generated from striatum- and nucleus accumbens-derived transporters, indicating that these polypeptides are highly similar in primary sequence. The proteolytic fragments generated by V8 protease were localized to specific domains of the protein using antipeptide antibodies corresponding to five different regions of the transporter. Fragments of 10 and 7 kDa from [125I]DEEP-labeled transporters were specifically immunoprecipitated with an antibody generated against amino acids 42-59 (near the first putative trans-membrane domain), whereas a 34-kDa fragment from [125I]RTI 82-labeled transporters was precipitated with three different sera corresponding to regions in the carboxyl-terminal two thirds of the protein. None of the V8 fragments smaller than 45 kDa, containing either photolabel, was altered in molecular mass by N-deglycosylation. The results indicate that photoincorporation of [125I]DEEP occurs in the amino half of the dopamine transporter, near the first two transmembrane helices, whereas [125I]RTI 82 labels the carboxyl-terminal region of the protein, between transmembrane domains 4 and 12.
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PMID:Photoaffinity-labeled ligand binding domains on dopamine transporters identified by peptide mapping. 774 82

Dopamine transporters (DATs) are members of the Na+- and Cl--dependent neurotransmitter and amino acid transporter family predicted by hydrophobicity analysis to have 12 transmembrane-spanning helices. The structure of DAT was studied using the photoaffinity compounds [125I]1-[2-(diphenylmethoxy)-ethyl]-4-[2-(4-azido-3-iodophenyl) ethyl] piperazine ([125I]DEEP), a 1-(2-diphenylmethoxy)-ethyl-4-(3-phenyl propyl)piperazine (GBR analog), and [125I]-3beta-(p-chlorophenyl)tropane-2beta-carboxylic acid, 4'-azido-3'-iodophenylethyl ester ([125I]RTI 82), a cocaine analog, which had been shown in a previous study to become incorporated into different regions of the DAT primary sequence. The proximity of the photolabeled binding sites to integral membrane structures was investigated by subjecting photolabeled membrane suspensions to limited proteolysis with trypsin and separately analyzing the resulting membranes and supernatants for the presence of photolabeled DAT fragments. Trypsin treatment of [125I] DEEP-labeled membranes generated labeled 45- and 14-kDa DAT fragments that immunoprecipitated with an epitope-specific antiserum generated against amino acids 42-59 near the first putative transmembrane domain, whereas [125I]RTI 82 was found in 32- and 16-kDa tryptic fragments that precipitated with an antiserum directed against a sequence near transmembrane domain 4 (amino acids 225-238). All of the photolabeled fragments were recovered in the protease-treated membranes, indicating that they possess integral membrane structures that prevent their release from the membrane as soluble forms. The size of the two smallest fragments in conjunction with their retention in the membrane suggests that incorporation of the photoaffinity ligands occurs in or near membrane spanning regions and delineates the maximum possible distance between the transmembrane structures, incorporated photolabel, and antibody epitopes. Carbohydrate analysis of the fragments identified sialic acids and N-linked oligosaccharides exclusively on the 45-kDa [125I]DEEP-labeled fragment, which, based on size, would be expected to contain four consensus glycosylation sites between putative transmembrane domains 3 and 4. Photoaffinity labeling after trypsin treatment of membranes showed that the larger but not the smaller fragments retain binding capacity, as the 45- and 32-kDa fragments were capable of becoming photolabeled. Binding of photoaffinity ligands at these fragments was displaced with the same pharmacology as that of intact DATs. These results verify numerous aspects of DAT structure and topology heretofore only predicted from theoretical considerations and extend our knowledge of DAT structure-function properties.
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PMID:Dopamine transporter ligand binding domains. Structural and functional properties revealed by limited proteolysis. 870 57

A new low-molecular-mass (6767.8 Da) serine proteinase isoinhibitor has been isolated from oil-rape (Brassica napus var. oleifera) seed, designated 5-oxoPro1-Gly62-RTI-III. The 5-oxoPro1-Gly62-RTI-III isoinhibitor is longer than the Asp2-Pro61-RTI-III and the Ser3-Pro61-RTI-III forms, all the other amino acid residues being identical. In RTI-III isoinhibitors, the P1-P1' reactive site bond (where residues forming the reactive site have been identified as PnellipsisP1 and P1'ellipsisPn', where P1-P1' is the inhibitor scissile bond) has been identified at position Arg21-Ile22. The inhibitor disulphide bridges pattern has been determined as Cys5-Cys27, Cys18-Cys31, Cys42-Cys52 and Cys54-Cys57. The disulphide bridge arrangement observed in the RTI-III isoinhibitors is reminiscent of that found in a number of toxins (e.g. erabutoxin b). Moreover, the organization of the three disulphide bridges subset Cys5-Cys27, Cys18-Cys31 and Cys42-Cys52 is reminiscent of that found in epidermal growth factor domains. Preliminary 1H-NMR data indicates the presence of alphaalphaNOEs and 3JalphaNH coupling constants, typical of the beta-structure(s). These data suggest that the three-dimensional structure of the RTI-III isoinhibitors may be reminiscent of that of toxins and epidermal growth factor domains, consisting of three-finger shaped loops extending from the crossover region. Values of the apparent association equilibrium constant for RTI-III isoinhibitors binding to bovine beta-trypsin and bovine alpha-chymotrypsin are 3.3 x 109 m-1 and 2.4 x 106 m-1, respectively, at pH 8.0 and 21.0 degrees C. The serine proteinase : inhibitor complex formation is a pH-dependent entropy-driven process. RTI-III isoinhibitors do not show any similarity to other serine proteinase inhibitors except the low molecular mass white mustard trypsin isoinhibitor, isolated from Sinapis alba L. seed (MTI-2). Therefore, RTI-III and MTI-2 isoinhibitors could be members of a new class of plant serine proteinase inhibitors.
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PMID:Characterization of low-molecular-mass trypsin isoinhibitors from oil-rape (Brassica napus var. oleifera) seed. 1010 60

The design of chimeric proteins is a major field of interest in structural biology and biotechnology. The successful design of the chimeric protein composed by the minimized reactive site domain of the low-molecular-mass trypsin inhibitor from Brassica napus (var. oleifera) seed (Ser3-Lys35; mini-RTI-III) and murine dihydrofolate reductase (DHFR) is reported here. The DHFR-mini-RTI-III chimeric protein was expressed in Escherichia coli, purified by metal-chelate affinity chromatography and oxidatively refolded. The affinity of the purified and refolded DHFR-mini-RTI-III for bovine trypsin (K = 5.0 x 10(-10) M) was closely similar to that determined for native RTI-III (K = 2.9 x 10(-10) M), at pH 8.2 and 22.0 degrees C. DHFR-mini-RTI-III may be regarded as a tool in structure-function studies and for developing multifunctional and multidomain proteinase inhibitors.
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PMID:A chimeric mini-trypsin inhibitor derived from the oil rape proteinase inhibitor type III. 1097 4

Five new low-molecular-mass trypsin inhibitors belonging to the RTI/MTI-2 family were identified from white mustard (Sinapis alba L. ; MTI-2) seed. Purified MTI-2 consisted of a peptide mixture, displaying Ile or Arg at position 43, Trp or kynurenine (Kyn) at position 44, and C-terminal ragged ends. The occurrence of Ile or Arg at position 43 suggested that MTI-2 inhibitors originated from different genes. The presence of 5-oxo-proline (pyroglutamic acid; 5-oxoPro1) and Kyn44 reflected post-translational processing of the serine proteinase inhibitor. MTI-2 showed approximately 70% amino-acid identity with low-molecular-mass trypsin inhibitors isolated from oil rape (Brassica napus var. oleifera; RTI-III) seed and with serine proteinase inhibitors mapped in Arabidopsis thaliana chromosome II (ATTI). Furthermore, MTI-2 was homologous to brazzein, the sweet-tasting protein from Pentadiplandra brazzeana Baillon fruit ( approximately 30% amino-acid identity). Although snake-venom toxins showed a low amino-acid identity (< 20%) with MTI-2, RTI-III, and ATTI, some structurally relevant residues were conserved. The disulfide bridge pattern of MTI-2 (Cys5-Cys27, Cys18-Cys31, Cys42-Cys52, and Cys54-Cys57) corresponded to that of RTI-III and of snake-venom toxins, being different from that of brazzein. Therefore, protein similarity might be attributable to the three-dimensional arrangement rather than to the amino-acid sequence. Values of Ka for MTI-2 binding to bovine beta-trypsin (trypsin) and bovine alpha-chymotrypsin were 6.3 x 109 M-1 and 2.0 x 106 M-1, respectively, at pH 8.0 and 21.0 degrees C. Moreover, values of kon for MTI-2 binding to trypsin and of koff for the dissociation of the serine proteinase:inhibitor complex were 5.6 x 105 M-1.s-1 and 8.9 x 10-5 M-1.s-1, respectively, at pH 8.0 and 21.0 degrees C. Despite the heterogeneity of the purified inhibitor peptide mixture, the inhibition properties of the different MTI-2 inhibitors were indistinguishable.
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PMID:Characterization of five new low-molecular-mass trypsin inhibitors from white mustard (Sinapis alba L.) seed. 1102 93

The role of viral respiratory infections in lactating infants and other children continues to generate controversy. The debate concerns the difference, or the apparent differences, in the natural history of wheezing. Viral infections frequently provoke wheezing episodes in non-asthmatic small children but in the majority of these the wheezing disappears without the child subsequently developing asthma. In some cases, however, the wheezing persists and in others the child has asthma. Both the role of viral infection and the mechanisms by which wheezing can be produced in a previously healthy child or exacerbated in asthmatic children are unknown. Several hypotheses have been put forward to explain the relationship between viral infections and persistent wheezing and asthma: 1. Altered immune response to various allergens, whether producing sensitization to these allergens or inhibiting tolerance response to airborne allergens. The number of such patients is increasing, among them those with bronchiolitis, asthma, positive skin tests and specific IgE antibodies. Although there is no unanimity on the matter, these patients also present elevated IL-4 levels and reduced IFN-gamma levels. 2. Induction of inflammation typical of allergic asthma. This occurs when the virus interacts with T lymphocytes; (the natural response to viral infection is Th0 and Th1 lymphocyte differentiation and release of IFN-gamma, which has antiviral properties. In children infected with respiratory syncytial virus Th2 lymphocyte differentiation is produced, which is characteristic of allergic reactions, to the detriment of Th1); epithelial cells (in these cells active viral infection activates nuclear transcription kappa-beta and nuclear IL-6 factor, producing the release of numerous pro-inflammatory cytokines and chemokines as well as expression of adhesion molecules); eosinophils (inducing variable eosinophilia which, to a certain degree, has predictive value for the persistence of wheezing) and other inflammatory cells such as neutrophils and macrophages. In the same context, during viral respiratory infection, the presence of mediators (leukotrienes, especially LTC4, histamine, prostaglandins and tryptase) are observed in respiratory secretions and a correlation between levels of specific IgE mediators can be observed. 3. Increased allergic inflammation--producing bronchial hyperreactivity, mediator release by the various inflammatory cells and neuropeptides from C-sensitive fibers, and even interfering with nitric oxide bronchodilators. In spite of all of the above, it seems that recurrent wheezing after childhood bronchiolitis is not exclusively the result of viral infection and that other factors also play a role in this disease.
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PMID:[Viral infection and asthma: immunologic mechanisms]. 1143 87


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