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)

An extracellular protein-polysaccharide-lipide (PPL) complex from exponentially growing cultures of Myxococcus virescens was purified by phosphate precipitation and gel chromatography. The high molecular weight slime polymer appeared homogenous upon isoelectric focusing. The PPL complex exhibited proteolytic activity against gelatin and the activity was only partly reduced by heat treatment. The function of the slime polymer as protein denatured was studied. The complex formed micelles similar to anionic detergents and it inhibited the precipitation and coagulation of proteins by trichloroacetic acid. Lysozyme was totally inactivated when treated with the PPL complex. By gel chromatography binding studies, the PPL complex was found to bind lysozyme in the ratio of 1 to 5.8 (w/w). After separation of added protein from the complex the anticoagulation effect on the protein remained. The biological function of the PPL complex was demonstrated with hemoglobin. When all susceptible peptide bonds in PPL-treated hemoglobin were hydrolyzed by trypsin only 20% in the urea-denatured protein were attacked. The combined role of slime and proteolytic activity is discussed.
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PMID:Myxobacterial slime and proteolytic activity. 41 87

The absorption spectra of fluram, lysozyme, horse-radish peroxidase, and mixtures of lysozyme + fluram and peroxidase + fluram and the fluorescence and fluorescence excitation spectra of the mixtures in 0.05 M phosphate buffer with 1 per cent dioxane are determined. Due to formation of a protein-fluram compound, the absorption spectra of the mixtures are not algebraic sums of the components. From the fluorescence intensities the number of bonding sites is found 6 in both cases. The fluorescence spectrum of the peroxidase-fluram compound has maxima at 305, 350, 400, 450 nm due to peroxidase and at 480 nm originating from fluram. In mixtures of 10(-5) M lysozyme + 10(-4) M fluram, 3/4 of the excitation energy is transferred from lysozyme to fluram within the compound under 280 nm excitation. Under similar conditions 4/5 of the excitation energy is transferred from peroxidase to fluram.
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PMID:Absorption and fluorescence of fluram-labelled lysozyme and peroxidase solutions. 55 45

The photodynamic inactivation of lysozyme in air saturated H2O and D2O (phosphate buffer 0.05 M, pH 7.0) in the presence of methylene blue and riboflavin has been studied. When H2O was replaced by D2O a great increase in the rate of photoinactivation of lysozyme was observed. This finding, together with the fact that photooxidation is inhibited by singlet oxygen quenchers like NaN3, suggests that these reactions occur via a singlet oxygen mechanism. During the course of the studies of the riboflavin sensitized photoinactivation of lysozyme, it was found that riboflavin is strongly bound to the enzyme as a result of illumination. This finding would explain the higher quantum yield observed when riboflavin is used, although this dye is bleached during irradiation.
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PMID:Light-induced binding of riboflavin to lysozyme. 59 15

Anionic sites on the surface of Brucella canis were visualized in the electron microscope by staining with positively charged ferric oxide hydrosols in acetic acid (AI-reagent), or propanoic acid (PI-reagent), and with a polycationic ferritin derivative. With the AI-reagent, single or small aggregates of ferric oxide particles were bound to the cell surface of Br. canis, whereas, with the lipophilic PI-reagent, the microorganisms were heavily stained with focal aggregates of iron granules. The polycationic ferritin label was uniformly distributed over the entire cell surface of Br. canis. The ferritin label was not bound on the surface of the organisms after prior treatment with trichloroacetic acid or methanolic hydrochloric acid. Treatment with aqueous acetone, chloroform/methanol, diethyl ether, sodium deoxycholate, pronase, lysozyme, hyaluronidase, and sodium periodate neither influenced the morphology of the Brucella nor diminished their ionic binding sites. Our results indicate that the anionic sites on the cell surface of Br. canis may be carboxyl and phosphate groups of lipopolysaccharides.
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PMID:[Ultrastructural investigations on anionic surface sites of Brucella canis (author's transl)]. 60 17

Mutagenesis in extracellular phage sd by 8-metoxypsoralen (8-MOP) and longwave (lambda greater than 310 nm) UV-irradiation has been established. The kinetics of lethal and mutagenic effects of 8-MOP+light was studied. The efficiency of mutagenesis on the first linear part of mutation curve was 0.3% per the lethal hit which is 2 times lower than that of shortwave (lambda=254 nm) UV-irradiation. The maximum yield of mutants makes up 1%, after which the mutation curve is maintained. It has been established that the main (may be the only) contribution into mutagenesis is made by monoadducts, whereas the lethal effect is conditioned by diadducts (cross-links). The comparison of the efficiency of mutagenic effects of 8-MOP+light with mutagenic effects of other kinds of irradiations was carried out. The possibility of repair of damaged 8-MOP+light phage sd DNA by transfection of Escherichia coli C (uvr+) and Cs (uvr-) lysozyme spheroplasts has been established. The repair mechanism of photodamage in intact phage sd induced with 8-MOP+light was also investigated using the method of two-step irradiation. It has been shown that 65% of photodamages are repaired in E. coli SK cells in the M9 medium, i. e. under cellular metabolism. The recovery of phage sd is completely inhibited in phosphate buffer. Unlike chloramphenicol (150 microgram/ml), 1% caffeine blocks the phage recovery only by 30%. The participation of phage sd determining enzymes in its intracellular recovery from 8-MOP+light damages is assumed.
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PMID:[Photosensitizing effect of 8-methoxypsoralen on bacteriophage cd]. 68 May 61

Previously, di-isopropylphosphorofloridate (DFP) was shown to inhibit the release of lysosomal enzymes induced by chemotactic factors. It was suggested that the inhibition was due to the phosphorylation of a cell bound serine esterase activated by the chemotactic factor. However, as shown here, di-isopropyl methyl phosphate, a nonphosphorylating analogue of DFP, inhibits just as well as DFP, the release of lysozyme and beta glucuronidase from rabbit polymorphonuclear leucocytes induced by chemotactic factor in the presence of cytochalasin B. Similarly, the poorly phosphorylating phenyl ethyl pentylphosphonate and phenyl ethyl phenylpropylphosphonate inhibit enzyme release, induced under the same conditions, as well as or better than the corresponding good phosphorylators, p-nitropheny ethyl pentylphosphonate and p-nitrophenyl ethyl phenylpropylphosphonate. Phenyl ethyl pentylphosphonate inhibits at least as well or probably better than p-nitrophenyl ethyl pentyl phosphonate, the chemotactic factor induced relase of lysozyme from polymorphonuclear leucocytes spread on Millipore filters in the absence of cytochalasin B. We conclude that, under the circumstances tested, there is no evidence that the release of lysosomal enzymes from rabbit peritoneal polymorphonuclear leucocytes induced by chemotactic factor involves the activation of an esterase.
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PMID:Organophosphorus inhibition of lysosomal enzyme secretion from polymorphonuclear leucocytes. Evidence of a lack of a requirement for esterase activation. 75 Mar 74

Human supragingival dental plaque was collected from patients with various degrees of caries and periodontal disease. Plaque extracts, prepared in five different solutions (four varied from pH 1.8 to 12.7; one contained urea), were analyzed by polyacrylamide gel electrophoresis, and tested for amylase and lysozyme enzyme activity. Because no qualitative or quantitative advantages of using the extremes of pH or urea were observed, all subsequent extracts were prepared in phosphate buffered saline at pH 7.3. Concentrated extracts were fractionated by gel filtration and characterized by polyacrylamide gel electrophoresis, peptide mapping, molecular weight estimation, determination of enzymatic activities and amino acid and carbohydrate analyses. Regions of similarity among the gels were revealed by comparing the electrophoretic patterns of pooled plaque extract, normal serum and whole saliva. The elution pattern of pooled plaque extract from a standardized Sephadex G-200 column indicated the presence of both high and low molecular weight proteins that might have correlated with the components of normal serum and saliva. A predominant and dialyzable third fraction had no correlate in either serum or saliva. The small peptides in this fraction were subjected to amino acid, carbohydrate and peptide map analyses. The most abundant amino acids were alanine, glutamic acid, glycine, valine, leucine, lysine and serine. These small components contained no neutral or amino sugars. Pooled plaque extract and the small peptides exhibited similar peptide maps.
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PMID:Studies on human dental plaque. 1. Physical and chemical characteristics and enzyme activities of pooled plaque extracts. 80 55

Pseudomonas aeruginosa grows at an apparent reduced rate at 46 C as compared with the rate at 37 C, when growth is measured as an increase in absorbance. Cells at 46 C are long, plasmolyzed, nonmotile filaments. The filaments contain phase-dark material that may be chromosomal in nature. When the 46 C culture is shifted to 37 C, the filaments fragment at polar ends after flagella form, and the final number of cells is equal to the number of chromosomal "packets" observed within the filament. The outer envelope of the filament appears to be structurally complete as determined by biochemical, thin section, and freeze-etch examination. When filaments are treated with lysozyme, they form large spheroplasts, suggesting that the outer wall and the cytoplasmic membrane are continuous within the filament. Filaments produce little or no periplasm-located alkaline phosphatase (APase), but activity appears immediately after a shift to 37 C. Cells grown at 37 C and shifted to 46 C remain as single, nonmotile, rods or doublets, and the APase formed at 37 C remains stable at 46 C. The addition of APase or inorganic phosphate is partially or completely effective as an inducer of filament fragmentation at 46 C. The results suggest that periplasm-located APase is an important enzyme in the final stages of cell division when P. aeruginosa is cultured on inorganic phosphate-limiting media.
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PMID:Cell division in Pseudomonas aeruginosa: participation of alkaline phosphatase. 81 77

The alkaline phosphatase activities of five unique isolates of marine bacteria were found to be associated with the periplasmic space; however, the enzymes from these isolates differed with respect to their repressibility, the apparent number of isoenzymes, the necessity for Mg2 for activity, and the conditions required for their release. With three of the isolates, the enzyme was released when cells that had been washed in 0.5 M NaCl were suspended in sucrose; however, with the other two isolates, one required the additional presence of tris(hydroxymethyl)aminomethane and the other required the presence of lysozyme and ethylenediaminetetraacetic acid. In two isolates the activity was constitutive, in two it was partially repressed, and in one it was completely repressed by inorganic phosphate. The repression of activity was associated with corresponding changes of activity bands as seen by acrylamide gel electrophoresis.
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PMID:Biochemical and physiological properties of alkaline phosphatases in five isolates of marine bacteria. 84 25

An enzyme capable of hydrolyzing the substrate L-alanine p-nitroanilide has been found in the various Escherichia coli strains tested. This enzyme has been called aminoendopeptidase since it shows both activities (see accompanying paper). It is released from the cells by osmotic shock and by lysozyme -- EDTA spheroplasting treatment, and 50% of the total activity is directly detectable with suspensions of intact cells. However, the release by osmotic shock or spheroplasting is not as efficient as it is for alkaline phosphatase. This periplasmic aminoendopeptidase is constitutively produced but the differential rate of synthesis is increased 4-fold when the cell growth is limited by Pi. The occurrence of this 'derepression' is simultaneous with that of alkaline phosphatase. Increasing the concentration of inorganic phosphate in the medium has no effect on the constitutive aminoendopeptidase synthesis. The effect of phosphate starvation is specific since starvation for neither nitrogen nor carbon and energy source are effective in derepressing aminoendopeptidase.
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PMID:Evidence for an aminoendopeptidase localized near the cell surface of Escherichia coli. Regulation of synthesis by inorganic phosphate. 110 39


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