Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Syringacin 4-A, a bacteriocin produced by Pseudomonas syrinagae 4-A, was obtained by induction with ultraviolet irradiation or mitomycin C. Approximately 1,000-fold purification of the bacteriocin was achieved by manganous chloride precipitation, differential centrifugation, and chromatography on hydroxyapatite columns. The purified syngacin was homogeneous on hydroxyapatite columns and sucrose density gradients; it also sedimented as a single entity in the analytical ultracentrifuge. The buoyant density of purified syringacin in cesium chloride was 1.294 g/ml. The sedimentation coefficient was calculated as 120S, and the diffusion coefficient was 6.49 x 10(-8) cm(2)/s. The molecular weight was calculated as 1.6 x 10(7) from physical data and 1.7 x 10(7) from biological data. The syringacin was composed of about 88.4% protein, 8.5% arabinose, 2.2% galacturonic acid, and 0.7% glucosamine. Amino acid analysis indicated a predominance of leucine (12.1%), aspartic acid (12.2%), and glutamic acid (12.7%). The ultraviolet spectrum showed a maximum absorbance peak at 276 nm. The syringacin was heat and alcohol sensitive, but resistant to trypsin, chymotrypsin, carboxypeptidase, Pronase, protease, lysozyme, steapsin, deoxyribonuclease, and ribonuclease. Maximum pH stability was between 5 and 8. Crude bacteriocin was stable at room temperature for at least a year, and purified material was stable for at least 3 months at 4 C.
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PMID:Purification and characterization of syringacin 4-A, a bacteriocin from pseudomonas syringae 4-A. 1582 74

Some properties of the cell-free and cell-associated hemolysins of Escherichia coli were studied. Several strains of E. coli that were isolated from intestines of pigs with edema disease produce large quantities of cell-free hemolysin when grown in the presence of an extract of meat. The component of meat that stimulates production of cell-free hemolysin is not extracted by lipid solvents and is not dialyzable. The cell-free hemolysin is an acidic substance that occurs in two forms. It is inactivated by trypsin but not by lecithinase, lysozyme, ribonuclease, or deoxyribonuclease, shows optimum activity between pH 7 and 8, and requires calcium ion for activity. It does not appear to be an enzyme. The kinetics of the lytic reaction are most consistent with the hypothesis that one molecule of cell-free hemolysin is sufficient to lyse one erythrocyte and that it is inactivated in the lytic reaction. The cell-free hemolysin does not sufficiently damage the cell during the prelytic period to cause lysis after the hemolysin-calcium-erythrocyte complex has been disrupted. The cell-associated hemolysin was not separated from the cell by autolysis, freezing, sonic treatment, or treatment with trypsin or lysozyme. It appears to be closely associated with the metabolic status of the cell. Organisms that are highly hemolytic under usual conditions of assay immediately lose most of their hemolytic capability in the presence of sodium cyanide, streptomycin, nalidixic acid, and rifampin.
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PMID:Properties of the Hemolytic Activities of Escherichia coli. 1655 36

Osmoplast production in Pseudomonas aeruginosa was investigated to obtain osmotically sensitive cells for studies on the subcellular location of the paraffin-oxidizing enzyme system. It proved possible to convert cells of P. aeruginosa treated with lysozyme and ethylenediaminetetraacetic acid in tris(hydroxymethyl)aminomethane-sucrose buffer (pH 8) into osmotically sensitive cells within 2 min. Active, cell-free preparations were obtained by the subsequent osmotic disruption in the presence of deoxyribonuclease and magnesium chloride. The conditions necessary for a complete separation of membranes and soluble cell constituents were established by following the distribution of two reference enzymes. An enzyme assay based on direct gas chromatographic analysis of the oxidation products from n-heptane is described for the paraffin-oxidizing enzyme system. By using this method, we investigated the enzymatic organization and subcellular distribution of the paraffin-oxidizing enzyme system. It was confirmed that the enzyme system is composed of three components, each of which is indispensable for the hydroxylation of n-heptane. One of these components, the hydroxylase, was located in two cell fractions; the other two components occur exclusively in the soluble cell fraction. The half-life of a crude enzyme preparation kept at ambient temperature is approximately 3.5 hr. This poor stability was found to be primarily due to the instability of one of the soluble factors, presumably the reduced nicotinamide adenine dinucleotide-rubredoxin reductase.
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PMID:Paraffin Oxidation in Pseudomonas aeruginosa II. Gross Fractionation of the Enzyme System into Soluble and Particulate Components. 1655 78

From saline extracts of Phytolacca esculenta (shoriku) roots, two phytomitogenes were isolated by salting out with (NH4),SO4 and chromatography on DEAE-cellulose and Sephadex G-100 columns. Both fractions were homogeneous on disc electrophoresis and on immunoelectrophoresis. One of these (Fraction E-2) was shown to be similar to pokeweed mitogen in respect to mol. wt (32,000) and amino acid composition. The other (Fraction E-3) was a protein of 18,000 mol. wt. Both fractions had similar biological activities to pokeweed mitogen in their ability to stimulate pig blood lymphocytes in vitro to incorporate tritiated thymidine, and to induce blastoid transformation. Both fractions contained an unusually large amount of cystine, i.e., 18 half-cystine residues % for Fraction E-2 and 22 residues % for Fraction E-3. Although these mitogens were resistant to deproteinizing procedures such as perchloric acid treatment and Sevag's procedure, the DNA synthesis-stimulating activity was inactivated by digestion with Pronase E and Nagarse, but resistant to trypsin, chymotrypsin, deoxyribonuclease, ribonuclease, lysozyme and neuraminidase. The activity was stable at acidic and neutral pH (4-7) but unstable at alkaline pH. The activity at pH 7.3 was stabilized by the addition of Ca2+ or Mg2+. On the addition of more than 2 mM of Ca2+, precipitation of mitogen occurred. From the above results the molecular basis of the mitogenic activity of shoriku mitogen is discussed.
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PMID:Isolation and characterization of pokeweed mitogen-like phytomitogens from Shoriku, Phytolacca esculenta. 1999 19

Charge sensors based on nanoscale field-effect transistors are a promising new tool to probe the dynamics of individual enzymes. However, it is currently unknown whether the electrostatic signals associated with biological activity exceed detection limits. We report calculations of electrostatic signatures of two representative enzymes, deoxyribonuclease I and T4 lysozyme. Our simulations reveal that substrate binding to deoxyribonuclease and internal dynamics of lysozyme are detectable at the single-molecule level using existing point-functionalized carbon nanotube sensors.
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PMID:Modeling the electrostatic signature of single enzyme activity. 2016 62


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