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)

The recombinant plasmid pRI203 carries a Yersinia pseudotuberculosis chromosomal gene that makes E. coli K-12 HB101 strain able to synthetize an outer membrane protein, invasin, which interacts with integrin receptors of eukaryotic cells, enabling this microorganism to penetrate human cultured animal cells. In this study we evaluated the involvement of HeLa cell membrane structural components in the early phases of the invasive pathway of E. coli HB101 (pRI203). When HeLa cell monolayers were treated with several enzymes we showed that trypsin-, proteinase K- and neuraminidase-sensitive components are required for bacterial invasion. Comparison of the ability of simple and complex carbohydrates to inhibit bacterial invasion indicated that N-acetyl neuraminic acid, N-acetyl glucosamine and mucin were the most effective competitive inhibitors. Among glycolipids, gangliosides enhanced bacterial entry in HeLa cells. The results obtained suggest that N-acetyl neuraminic acid and N-acetyl glucosamine-containing glycoproteins and/or glycolipids participate as putative HeLa cell binding sites for the penetration process of E. coli HB101 (pRI203).
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PMID:Involvement of membrane carbohydrates of HeLa cells in the E. coli HB101 (pRI203) invasive pathway. 160 81

The inv locus of Yersinia enterocolitica is sufficient to convert a non-invasive Escherichia coli K12 strain into a microorganism that is able to penetrate cultured mammalian cells. The nucleotide sequence of inv reveals an open reading frame corresponding to an 835-amino-acid protein that is homologous to the invasin protein from Yersinia pseudotuberculosis. A polyclonal antiserum elicited by a synthetic peptide corresponding to the C-terminal 88 amino acids of this open reading frame detected a unique 100 kD protein in cell lysates of Y. enterocolitica strain 8081 c and in an E. coli strain harbouring the cloned inv gene. This protein localized to the outer membranes of both microorganisms and was cleaved by low concentrations of extracellular trypsin. HEp-2 cells were shown to attach to surfaces coated with bacterial outer membranes containing invasin and this attachment was destroyed by treatment of the membranes with trypsin. Thus it appears that the invasin protein from Y. enterocolitica is able to mediate both attachment to and entry of cultured epithelial cells.
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PMID:Sequence, localization and function of the invasin protein of Yersinia enterocolitica. 223 50

Yersinia intermedia produces a temperature-dependent (25 degrees C) bactericidal substance that is active against other Yersinia species. Crude preparations of the inhibitory substance were inactivated by chymotrypsin, trypsin, pronase, and heating but were not affected by lipolytic enzymes, chloroform, or other organic solvents. These data suggest that the active molecule is a bacteriocin of a proteinaceous nature. The molecular weight of the bacteriocin was estimated to be greater than 14,000. Exposure of agar fragments containing the active component to a pH range of 3 to 11 did not affect bactericidal activity. Bactericidal activity against the Y. frederiksenii indicator strain was shown by simultaneous and deferred antagonism and by the associative culture technique. The liquor from cell-free macerated agar fragments and broth cultures, however, were devoid of antibacterial activity.
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PMID:Partial characterization of Yersinia intermedia bacteriocin. 634 3

Yersinia enterocolitica serotype O3 was found to produce a haemolytic substance which could be released from the bacterial cells by sonic disintegration. The substance was non-dialysable, thermolabile, antigenic, and sensitive to trypsin. Chromatographic studies indicated a high molecular weight. Erythrocytes from different mammalian species differed in sensitivity to the haemolytic substance. Y. enterocolitica serotypes O8 and O9 produced no haemolytic substance.
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PMID:Studies on a haemolytic substance in Yersinia enterocolitica. 679 38

Purification of the envelope antigen of Yersinia pestis EV with passive hemagglutination activity is described. The purification procedure consisted of pancreatin digestion, chromatography on human erythrocyte stroma set on Celite, and rechromatography on Sephadex G-200. Chemical, physical, and biological properties of this antigen were investigated. The results show the lipid-polysaccharide structure of the isolated antigen. The carbohydrate moiety of the galactolipid antigen consists of galactose and fucose. The lipid fraction contained phosphatidylethanolamine and phosphatidylserine. The preparation showed high specificity in the hemagglutination reaction and in Y. pestis phage receptor activity. In two-dimensional immunoelectrophoresis, the isolated pancreatic envelope digest antigen appeared as a single line. Two-dimensional immunoelectrophoresis was modified for tandem separation and was employed to electrophoretically identify the pancreatic envelope digest, trypsin envelope digest preparation, and F1 envelope antigen of Y. pestis. Related or identical antigens showed confluence of peaks with reactions of identity.
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PMID:Chemical composition and biological activity of the Yersinia pestis envelope substance. 700

Heat-stable enterotoxin (ST) of Yersinia enterocolitica was produced under defined conditions. It was first detected in the culture supernatant of the late-logarithmic phase of growth and increased lineally during the the stationary phase of growth. The ST level became maximum at the decline phase of growth, and the ST was not detected in the lysate of bacteria obtained from the decline phase of growth. The ST was extensively purified from the culture supernatant, and about a 1,905-fold purification was achieved with a yield of 8.9%. The minimal effective dose of the purified ST was approximately 25 ng in the suckling mouse assay. The purified ST gave a single 280-nm absorbing peak on polyacrylamide disc gel electrophoresis and had a maximum absorption at 272 nm, and its molecular weight was 9,700 by Sephadex G-75 superfine gel filtration. The biological activity of the purified ST was lost by treatment with 2-mercaptoethanol, suggesting that the ST contained disulfide bridges in the molecule which were required for the development of toxic activity. The purified ST was heat stable at 100 degrees C for 10 min between pH 2.2 and 8.0, but not at pH values greater than 9.0 or in 2 N HCl. The treatment of the ST with trypsin resulted in a retarded elution of the ST activity by Sephadex F-75 superfine gel filtration and a passage through a UM-20 membrane filter.
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PMID:Further purification and characterization of heat-stable enterotoxin produced by Yersinia enterocolitica. 706 26

By using a suckling mouse assay, heat-stable enterotoxin (ST) was purified from the culture filtrate of Yersinia enterocolitica isolated from a diarrheal patient. The purification procedures involve ultrafiltration with an Amicon HIP-10 hollow fiber, ethanol fractionation, protamine sulfate treatment, diethylaminoethyl-Sephacel and hydroxylapatite column chromatographies, and Sephacryl S-200 superfine gel filtration. About 408-fold purification was achieved, with a yield of 12.0%. The minimal effective dose of purified ST was about 110 ng in the suckling mouse assay. The molecular weight of purified ST was 9,000 by Sephadex G-100 superfine gel filtration. The purified ST was stable to heating (100 degrees C for 20 min, 121 degrees C for 20 min) and did not lose its toxicity after treatment with protease, trypsin, lipase, phospholipase C, ribonuclease, deoxyribonuclease, beta-glucosidase, and neuraminidase. The purified ST was separated by isoelectric focusing into two active fractions, with pI's of 3.29 (ST-1) and 3.00 (ST-2), respectively. Antiserum from guinea pigs immunized with the purified ST neutralized the activity of both Y. enterocolitica ST and Escherichia coli ST.
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PMID:Partial purification and characterization of heat-stable enterotoxin produced by Yersinia enterocolitica. 721 60

A raw milk bacterial isolate, identified as Yersinia kristensenii was found to produce a bacteriocin which was inhibitory to Yersinia enterocolitica but not to other selected species of Yersinia or Gram-negative bacteria. Maximum production of bacteriocin was obtained when the organism was grown in shake culture at 28 degrees C. Mitomycin C at a concentration of 0.5 micrograms ml-1 induced bacteriocin production. The bacteriocin was partially purified and characterized by ammonium sulphate fractionation and gel filtration. The bacteriocin was completely inactivated when treated with proteolytic enzymes (trypsin and chymotrypsin). Bacteriocin activity was heat-resistant and it retained some of its activity after 5 min at boiling temperature. A total of 15 bacteriocin sensitive-suspected food isolates were further identified biochemically as Yersinia enterocolitica and a non-sensitive isolate was identified as Yersinia intermedia.
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PMID:Partial purification and characterization of bacteriocin from Yersinia kristensenii. 773 Feb 1

The 3,6-dideoxyhexoses, usually confined to the cell wall lipopolysaccharide of gram-negative bacteria, are essential to serological specificity and are formed via a complex biosynthetic pathway beginning with CDP-D-hexoses. In particular, the biosynthesis of CDP-ascarylose, one of the naturally occurring 3,6-dideoxyhexoses, consists of five enzymatic steps, with CDP-6-deoxy-delta 3,4-glucoseen reductase (E3) participating as the key enzyme in this catalysis. This enzyme has been previously purified from Yersinia pseudotuberculosis by an unusual procedure (protocol I) including a trypsin digestion step (O. Han, V.P. Miller, and H.-W. Liu, J. Biol. Chem. 265:8033-8041, 1990). However, the cloned gene showed disparity with the expected gene characteristics, and upon expression, the resulting gene product exhibited no E3 activity. These findings strongly suggested that the protein isolated by protocol I may have been misidentified as E3. A reinvestigation of the purification protocol produced a new and improved procedure (protocol II) consisting of DEAE-Sephacel, phenyl-Sepharose, Cibacron blue A, and Sephadex G-100 chromatography, which efficiently yielded a new homogeneous enzyme composed of a single polypeptide with a molecular weight of 39,000. This highly purified protein had a specific activity nearly 8,000-fold higher than that of cell lysates, and more importantly, the corresponding gene (ascD) was found to be part of the ascarylose biosynthetic cluster. Presented are the identification and confirmation of the E3 gene through cloning and overexpression and the culminating purification and unambiguous assignment of homogeneous E3. The nucleotide and translated amino acid sequences of the genuine E3 are also presented.
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PMID:CDP-6-deoxy-delta 3,4-glucoseen reductase from Yersinia pseudotuberculosis: enzyme purification and characterization of the cloned gene. 828 41

A proteolytic enzyme splitting casein and catalyzing the hydrolysis of the ester bond in the synthetic substrate, BAEE, in a trypsin-like manner, has been isolated from the cultural filtrate of Yersinia pseudotuberculosis using ultrafiltration and gel-filtration. The molecular mass of the enzyme is 110 kDa. The rate of hydrolysis is proportional to the enzyme and substrate concentrations which is typical for the kinetics of enzymatic reactions. The Km value for the Y. pseudotuberculosis enzyme is 2.5.10(-3) M. The optimal conditions for the enzymatic reaction are as follows: pH 7.4-8.0 (phosphate buffer) and 37 degrees C. The enzyme is inhibited by phenylmethylsulfonylfluoride and tosyllysinechlormethylketone, the specific inhibitors of serine proteinases and trypsin, respectively. These and literary data on bacterial proteinases are suggestive of their possible role as major factors in bacterial pathogenicity.
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PMID:[A secreted trypsin-like proteinase from Yersinia pseudotuberculosis]. 855 58


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