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)

Competent cells of group H streptococci strains Wicky and Challis autolyzed markedly when placed at 37 C in 0.05 m tris(hydroxymethyl)methyl-amino-propane sulfonic acid buffer (pH 9.0 to 9.1) containing 0.02 m 2-mercaptoethanol, whereas noncompetent cells autolyzed slightly. Autolysis of competent Wicky cells did not occur at 0 C or after the cells were heated at 100 C for 5 min. Culture fluids derived from strain Challis that contained competence factor (CF) activity did not contain lytic activity. Addition of native deoxyribonucleic acid (DNA) to competent Wicky cells caused a retardation in the rate of autolysis; ribonucleic acid and alkali-denatured DNA had less of an effect. Supernantant fluids derived from competent cell lysates lysed noncompetent Wicky cells but were inactive against cells of Hydrogenomonas eutropha, a group A Streptococcus, and against a commercial lysozyme substrate (Micrococcus lysodeikticus). This lytic activity was inactivated by heat (5 min at 100 C). Electron microscopic observations of autolyzed cells showed that autolysis occurs only at the site of cross-wall formation. A close relationship between the development of competence and autolysis is suggested by the fact that certain conditions that prevent the establishment of the competent state in Wicky populations (such as no CF, addition of CF simultaneously with chloramphenicol, and addition of trypsin-inactivated CF) also prevent autolysis. This observation emphasizes the indirect or inductive nature of CF on these processes.
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PMID:Autolytic activity associated with competent group H streptococci. 492 12

Serum from normal mammals agglutinated and immobilized nonpathogenic Leptospira biflexa and agglutinated avirulent lines of pathogenic serotypes L. icterohaemorrhagiae and L. zanoni. Virulent lines of L. icterohaemorrhagiae and L. zanoni were not affected, nor were any of three strains of L. pomona, one of which was avirulent. The active principle in serum was a beta-macroglobulin which was heat-labile and reduced by 2-mercaptoethanol, and acted in conjunction with complement and lysozyme; it was absorbable from serum by Formalin-treated susceptible leptospires. The Formalin-stable receptor antigen, named "Z antigen," is associated with virulence rather than pathogenicity, but may not be a determinant of virulence.
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PMID:Natural antibody in mammalian serum reacting with an antigen in some leptospires. 564 Mar 74

The activity of inorganic pyrophosphatase (EC 3.6.1.1) from Streptococcus faecalis ATCC 8043 decreased rapidly, when the cell extracts prepared by lysozyme and osmotic shock were incubated in a buffer solution (pH 8.0) at 25-50 degrees C. Increase in pH (from 8.5 to 10.5) retarded the inactivation considerably. The low activity level was reached in 2.5 h at 37 degrees C (pH 8.0) and this residual activity was stable during prolonged incubation. The enzyme in the form of low activity was not rapidly denatured until at 70 degrees C. The inactivation could be prevented and reversed by cysteine, dithiotreitol and 2-mercaptoethanol, but reductants, which do not contain SH-groups were not effective. Reduced glutathione slowed down and oxidized glutathione stimulated the inactivation. With pure enzyme it was shown that the low, stable activity level obtained with crude extracts during incubation is a property of inorganic pyrophosphatase and not due to another enzyme with a low capacity to hydrolyze inorganic pyrophosphate. These findings suggest that inorganic pyrophosphatase form S. faecalis exists in two interconvertible forms which differ in activity.
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PMID:Reversible changes in the activity of inorganic pyrophosphatase of Streptococcus faecalis. The effect of compounds containing SH-groups. 611 71

Hypochlorite-treated Clostridium botulinum 12885A spores, but not buffer-treated spores, could be germinated with lysozyme, indicating that their coats are made permeable to lysozyme by hypochlorite treatment so that the cortex is accessible. Hypochlorite-treated spores and spores extracted with 8 M urea-2-mercaptoethanol (pH 3.0) were sensitive to certain components of recovery media, but spores sensitized to lysozyme by other treatments were not. These data indicate that hypochlorite does more than increase coat permeability to lysozyme. Scanning electron microscopy revealed a more open-appearing surface of hypochlorite-treated spores, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that a greater amount of protein was removed from hypochlorite-treated and other lysozyme-sensitized spores than from buffer-treated spores. The data suggest that spore coat proteins may be removed by hypochlorite treatment, and this may be responsible for the sensitivity of spores and for their observed ability to germinate in lysozyme.
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PMID:Proposed mechanism for sensitization by hypochlorite treatment of Clostridium botulinum spores. 630 69

The protease-resistant proteins associated with the peptidoglycan (PG) of the phase I small-cell variant Coxiella burnetii were either partially released from the PG by boiling the PG-protein complex (PG-PC) in sodium dodecyl sulfate containing 2-mercaptoethanol and EDTA or totally released by 1 N NaOH hydrolysis at 23 degrees C. An 18,300-dalton protein was released from the PG-PC under reducing conditions, whereas 1 N NaOH treatment extracted PG-associated proteins without apparent dissolution of the PG. Purified PG was composed of muramic acid, glucosamine, glutamic acid, alanine, and meso-diaminopimelic acid in a molar ratio of 0.9:0.9:1.0:1.4:1.0. Lysozyme hydrolysis of cell walls, PG-PC, and purified PG caused an increase in reducing groups which correlated with roughly 60 to 100% digestion of disaccharides. There was no significant decrease in turbidity during lysozyme hydrolysis of cell walls and PG-PC; however, hydrolysis of purified PG caused about 90% decrease in turbidity. Approximately 60% of the meso-diaminopimelic acid groups of PG were not susceptible to dinitrophenylation, thus, demonstrating an apparent contribution of PG-associated proteins, rather than cross-linkage between peptides, to sacculus rigidity of cell wall and PG-PC. This association of PG and protease-resistant covalently bound proteins may be important structural and functional determiners of resistance to both environmental conditions and intracellular digestion of C. burnetii by eucaryotic cells.
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PMID:Sensitivity of Coxiella burnetii peptidoglycan to lysozyme hydrolysis and correlation of sacculus rigidity with peptidoglycan-associated proteins. 650 Dec 34

Sacculi prepared from Streptococcus sanguis 34 by extensive extraction of cells with hot sodium dodecyl sulfate-2-mercaptoethanol retained the ability to coaggregate with Actinomyces viscosus T14V. When S. sanguis 34 was disrupted by homogenization with glass beads and fractionated by differential centrifugation, only the cell wall fraction agglutinated A. viscosus T14V. When strain 34 was treated with lysozyme, the coaggregating capability of the cells was essentially unaltered. Sacculi prepared from lysozyme-treated strain 34 and additionally purified by electrophoresis were agglutinated by strain T14V.
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PMID:Specific coaggregation and the cell wall of Streptococcus sanguis. 687 47

An antagonistic strain of Streptococcus faecium was isolated from human feces, and it displayed a marked inhibition of bifidobacteria on agar plates. In liquid culture this isolate produced an antibacterial substance that can be partially purified by ammonium sulfate precipitation followed by gel filtration and ion-exchange chromatography. Its activity was assayed by the inhibition of growth of Bifidobacterium longum. The substance was sensitive to digestion by proteolytic enzymes and alpha-amylase, but was resistant to treatment with 6 M urea, dithiothreitol, 2-mercaptoethanol, ethyl ether, chloroform, and lysozyme. It was also stable to heating at 100 degrees C for 60 min. Its molecular weight was estimated to be about 50,000 by gel filtration.
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PMID:Streptococcus faecium-derived antibacterial substance antagonistic to Bifidobacteria. 741 52

The single histidine residue (His-15) in hen egg white lysozyme (EC 3.2.1.17) was chemically modified by diethyl pyrocarbonate (DEPC) to form exclusively the mono-N-carbethoxyimidazole adduct (second order rate constant of 252 +/- 16 M-1 min-1). Irreversible biscarbethoxylation of the His-15 imidazole ring by DEPC was observed when lysozyme was pretreated with 2-mercaptoethanol (2-ME), 2-ME plus 8 M urea, or 2-ME plus 1% (w/v) sodium dodecyl sulfate (SDS). Circular dichroism difference spectra were measured for the mono-N-carbethoxyimidazole derivatives of lysozyme, N alpha-acetyl-L-histidine, angiotensin-II, and O-carbethoxy-N alpha-acetyl-L-tyrosine. The circular dichroism difference spectrum for mono-N-carbethoxy lysozyme had one main band (delta [theta]244 nm = +17,000 degree. cm2.dmol-1) in the 240-260 nm region. Denaturing mono-N-carbethoxy lysozyme with 2-ME and 8 M urea (55 degrees C) or 1% SDS (100 degrees C) essentially abolished its circular dichroism difference spectrum in the 240-260 nm region without any decarbethoxylation. In this same region the circular dichroism difference spectra of DEPC-modified N alpha-acetyl-L-histidine and DEPC-modified angiotensin-II had two much weaker bands (delta [theta]233 nm = +1000 degree.cm2.dmol-1 and delta[theta]252nm = -600 degree.cm2.dmol-1 for N alpha-acetyl-L-histidine). This study reports the first characterization of circular dichroism associated with mono-N-carbethoxyhistidine in an enzyme (lysozyme), a peptide (angiotensin-II), and a model compound (N alpha-acetyl-L-histidine).
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PMID:Circular dichroism studies of diethyl pyrocarbonate-modified histidine in hen egg white lysozyme. 849 71

Protein disulfide isomerase has broad specificity in the catalysis of the formation and rearrangement of native disulfide bonds in proteins. This enzyme has two independent thioredoxin-like active sites (-CGHC-) and a peptide binding site. However, the mechanisms involving the catalytic processes are not clearly understood. It was reported that the enzyme associates with scrambled pancreatic ribonuclease A in vitro, and with misfolded human lysozyme in vivo. In the present study, recombinant human interleukin 2 has been chosen to probe the reaction intermediate in the reaction with the enzyme. We have identified and characterized a covalent associate formed in vitro by SDS-PAGE and Western blot analysis. This associate has a molecular weight of 71-72 kDa, the approximate sum of the molecular weights of the enzyme and the substrate. Western blot analysis confirmed that it formed via an intermolecular disulfide bond. Upon treatment with 2-mercaptoethanol, this bond was cleaved.
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PMID:Covalent association of protein disulfide isomerase with recombinant human interleukin 2 in vitro. 866 Mar 62

Two extracellular chitinases (FI and FII) were purified from the culture supernatant of Pseudomonas aeruginosa K-187. The molecular weights of FI and FII were 30,000 and 32,000, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 60,000 and 30,000, respectively, by gel filtration. The pIs for FI and FII were 5.2 and 4.8, respectively. The optimum pH, optimum temperature, pH stability, and thermal stability of FI were pH 8, 50 degrees C, pH 6 to 9, and 50 degrees C; those of FII were pH 7, 40 degrees C, pH 5 to 10, and 60 degrees C. The activities of both enzymes were activated by Cu2+; strongly inhibited by Mn2+, Mg2+, and Zn2+; and completely inhibited by glutathione, dithiothreitol, and 2-mercaptoethanol. Both chitinases showed lysozyme activity. The purified enzymes had antibacterial and cell lysis activities with many kinds of bacteria. This is the first report of a bifunctional chitinase/lysozyme from a prokaryote.
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PMID:Purification and characterization of two bifunctional chitinases/lysozymes extracellularly produced by Pseudomonas aeruginosa K-187 in a shrimp and crab shell powder medium. 902 18


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