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)

We have studied the role of arachidonic acid (AA) metabolism in the release of lysosomal enzymes (beta-glucuronidase and lysozyme) from human polymorphonuclear leukocytes (PMNs). 5,8,11,14-Eicosatetraenoic acid (ETYA), which inhibits both the cyclo-oxygenase and the lipoxygenase pathways of AA metabolism, was found to cause a dose-dependent inhibition of lysosomal enzyme release from human PMNs induced by immunological (i.e., serum-treated zymosan: Zx) and nonimmunological stimuli (i.e., formyl methionine-containing peptide and the Ca2+ ionophore A23187). In contrast, the non-steroidal anti-inflammatory drugs (indomethacin, meclofenamic acid and aspirin), which only block the cyclo-oxygenase pathway of AA metabolism, had little effect on enzyme release from PMNs induced by the same stimuli. 5,8,11-Eicosatriynoic acid (ETI), a selective inhibitor of the lipoxygenase pathway of AA metabolism, caused a dose-dependent inhibition of lysosomal enzyme release elicited by Zx, f-met peptide, and A23187. p-Bromophenacyl bromide (BPB), which inhibits the phospholipase A2 (PLA2) activity in several tissues, was found to cause a dose-dependent inhibition of lysosomal enzyme release induced by the same immunological and non-immunological stimuli. The inhibitory effect of BPB on enzyme release was irreversible and extremely rapid. It appears that activation of PLA2 and the products of the AA metabolism, generated via a lipoxygenase pathway, play an essential role in the biochemical control of human PMNs activation and secretion.
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PMID:Possible role of arachidonic acid and of phospholipase A2 in the control of lysosomal enzyme release from human polymorphonuclear leukocytes. 664 91

Free radicals derived from one-electron oxidation of the amino acids tryptophan, tyrosine, methionine and histidine have been found to be rapidly (k = 10(7) -10(9) dm3 mol-1 s-1) and efficiently repaired by Trolox C, a vitamin E analogue. The reactions form a relatively stable phenoxyl radical of Trolox C (lambda max = 440 nm; epsilon = 5.4 X 10(3) mol dm-3 cm-1). The radical cation of tryptophan is more rapidly repaired than the neutral tryptophan radical. Repair of tryptophanyl radicals in the enzyme lysozyme has also been observed. The results suggest that a function of alpha-tocopherol in membranes may be the repair of radicals of integral membrane proteins.
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PMID:Repair of amino acid radicals by a vitamin E analogue. 670 21

We have studied the mechanisms by which amino acid starvation of Escherichia coli induces resistance against the lytic and bactericidal effects of penicillin. Starvation of E. coli strain W7 of the amino acids lysine or methionine resulted in the rapid development of resistance to autolytic cell wall degradation, which may be effectively triggered in growing bacteria by a number of chemical or physical treatments. The mechanism of this effect in the amino acid-starved cells involved the production of a murein relatively resistant to the hydrolytic action of crude murein hydrolase extracts prepared from normally growing E. coli. Resistance to the autolysins was not due to the covalently linked lipoprotein. Resistance to murein hydrolase developed most rapidly and most extensively in the portion of cell wall synthesized after the onset of amino acid starvation. Lysozymes digests of the autolysin-resistant murein synthesized during the first 10 min of lysine starvation yielded (in addition to the characteristic degradation products) a high-molecular-weight material that was absent from the lysozyme-digests of control cell wall preparations. It is proposed that inhibition of protein synthesis causes a rapid modification of murein structure at the cell wall growth zone in such a manner that attachment of murein hydrolase molecules is inhibited. The mechanism may involve some aspects of the relaxed control system since protection against penicillin-induced lysis developed much slower in amino acid-starved relaxed controlled (relA) cells than in isogenic stringently controlled (relA+) bacteria.
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PMID:Alteration of Escherichia coli murein during amino acid starvation. 677 63

The N-acetylglutamate deacetylase (EC 3.5.1.-) from Pseudomonas aeruginosa, strain PAO1, was purified 15,000-fold to electrophoretic homogeneity. The enzyme was distinct from acetylornithinase and formylglutamate hydrolase. Its molecular weight was estimated to be 90,000 by gel filtration and by sedimentation in sucrose gradients. Electrophoresis in sodium-dodecyl sulphate gels gave a single band corresponding to a molecular weight of 44,000. N-Acetylglutamate deacetylase was L-specific and showed no peptidase activity. Among 17 N-acetyl-L-amino acids tested as substrates, N-acetyl-L-glutamine, N-acetyl-L-methionine and N-acetylglycine were hydrolysed at 20% of the rate of N-acetyl-L-glutamate whereas other N-acetyl-L-amino acids were deacetylated at a rate of less than 10%. The catalytic activity depended on Co2+. The Km of the enzyme with respect to N-acetylglutamate was 1.43 mM. Preparation of spheroplasts with lysozyme in the presence of 0.2 M-MgCl2 led to the release of 80% of the enzyme activity from the cells, indicating the periplasmic localization of N-acetylglutamate deacetylase. Its localization in the periplasmic space explains the inability of P. aeruginosa argA mutants to grow on N-acetylglutamate, which is utilized by the wild-type as a carbon and nitrogen source.
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PMID:Properties and localization of N-acetylglutamate deacetylase from Pseudomonas aeruginosa. 680 Nov 90

Outer membrane proteins were derived from one rough and four smooth strains of Brucella abortus by sequential extraction of physically disrupted cells with N-lauroylsarcosinate and dipolar ionic detergent. Extraction of outer membrane proteins was ineffective, however, without predigestion with lysozyme. Three groups of proteins were present and could be separated in their native state by sequential anion-exchange chromatography and gel filtration. Membrane proteins contained substantial quantities of tightly adherent lipopolysaccharide which could be reduced but not eliminated by extraction of cells with trichloroacetic acid before disruption. Group 2 proteins, apparently trimers in their native state, gave rise to 43,000- and 41,000-molecular-weight bands after complete denaturation in sodium dodecyl sulfate. They were antigenically identical among all the strains, showed close resemblance in amino acid composition to each other and a general similarity to OmpF of Escherichia coli, and are proposed to be the porins of B. abortus. Group 3 proteins occurred as 30,000-molecular-weight bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, although additional bands were frequently observed in this region. In none of the strains did group 3 proteins manifest heat-modifiable characteristics. Proteins of different strains bore a high degree of similarity to each other in amino acid composition, except in methionine, isoleucine, tyrosine, and histidine. Differences occurred consistently in amino acid composition between group 2 and 3 proteins, and some of these correspond to differences between OmpF and OmpA. Group 2 and 3 proteins were antigenically distinct from each other, but the principal group 3 antigens were shared among all the strains. Despite the lack of heat modifiability, perhaps influenced by adherent lipopolysaccharide, group 3 proteins are proposed as counterparts to OmpA. Most of the group 1 proteins, minor components, were physically associated with those of group 3 unless in sodium dodecyl sulfate. Group 1 proteins produced a major band at 94,000 and exhibited heat modifiability. No evidence was found of a low-molecular-weight lipoprotein in the outer membrane of B. abortus, but this is not taken to exclude its occurrence.
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PMID:Outer membrane proteins of Brucella abortus: isolation and characterization. 680 64

The spore-coat fraction from Bacillus megaterium KM, when prepared by extraction of lysozyme-digested integuments with SDS (sodium dodecyl sulphate) and urea, contains three N-terminal residues and a major component of apparent mol.wt. 17500. Electron microscopy of this fraction shows it to consist of an ordered multilamellar structure similar to that which forms the coat region of intact spores. The 17500-dalton protein, which has been purified to homogeneity, has an N-terminal methionine residue, has high contents of glycine, proline, cysteine and acidic amino acids and readily polymerized even in the presence of thiol-reducing agents. It is first synthesized between late Stage IV and early Stage V, which correlates with the morphological appearance of spore coat. Before Stage VI the 17500-dalton protein is extractable from sporangia by SDS in the absence of thiol-reducing reagents. Between Stage VI and release of mature spores the protein becomes resistant to extraction by SDS unless it is supplemented by a thiol-reducing reagent. In addition to that of the spore-coat protein, the timing of synthesis of all the integument proteins was analysed by SDS/polyacrylamide-gel electrophoresis and non-equilibrium pH-gradient electrophoresis. Several integument proteins are conservatively synthesized from as early as 1h after the end of exponential growth (t1), which may reflect protein incorporation into the spore outer membrane.
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PMID:Characterization, purification and synthesis of spore-coat protein in Bacillus megaterium KM. 680 68

A study has been made of the proteins in the vitelline membrane of hen's eggs before and after mechanical separation into the inner and outer layers. The membranes were dissolved in detergent (sodium dodecyl sulphate) and chromatographic fractions were examined by gel electrophoresis. The separated inner and outer layers were compared by gel electrophoresis. The outer layer contained (i) enzymically active lysozyme (EC 3.2.1.17) (about 60% dry weight), (ii) an insoluble ovomucin complex and (iii) a new protein, VMOI (vitelline membrane outer I). These account for most of the protein. In addition, some minor constituents were detected by gel electrophoresis but were not isolated. Except for ovomucin, the constituents of the outer layer could be dissolved from the membrane at high ionic strength (greater than 0.5 M sodium chloride), resulting in a loss of its structure. On lowering the ionic strength the soluble proteins recombined with the membrane, partially regenerating the original structure. Ovomucin appears to form the skeleton of the outer layer, but the salt-soluble proteins, especially lysozyme, are responsible for its integrity. The function of the newly-recognized protein (VMOI) is not known. Its molecular weight is 17,500 according to gel electrophoresis in detergent and it contains no methionine. The inner layer consists largely of the proteins GPI, GPII and GPIII isolated by Kido et al. (Kido, S., Janado, M. and Nunoura, H. (1975) J. Biochem. 78, 261-268) from the whole membrane.
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PMID:Proteins of the outer layer of the vitelline membrane of hen's eggs. 711 29

Fumarase (EC 4.2.1.2) and mitochondrial L-malate dehydrogenase (EC 1.1.1.37) were both inhibited by NaAuCl4 and KAuBr4. The inhibition for both was measured as a function of gold complex concentration and aquation time, and the NaAuCl4 inhibition was also measured in the presence of 0.15 M NaCl. Regeneration of the enzyme activity after NaAuCl4 inhibition using L-cysteine, L-methionine and NaCN was also investigated. Sodium dodecyl sulfate (SDS) acrylamide gel electrophoresis and amino acid analysis was performed on the NaAuCl4 inhibited enzymes as well as on ribonuclease A (EC 3.1.26.2), lysozyme (EC 3.2.1.17) and liver alcohol dehydrogenase (EC 1.1.1.1). It was observed that the inhibition was proportional to the gold complex concentration but decreased markedly after aquation of the complex. In the presence of NaCl the initial rate of inactivation is essentially unaffected unless the complex has been aquated and then the initial rate is increased. Gel electrophoresis on gold complex-enzyme mixtures show polymerization for ribonuclease and lysozyme and amino acid analysis indicates that no oxidation has taken place. From these results, a binding mechanism is postulated for the inhibition of the dehydrogenases by direct displacement of a halide ligand, probably by two groups on the enzyme, at least one of which may be a sulfur containing acid.
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PMID:Inhibition of two mitochondrial enzymes by gold (III) halo complexes. Evidence for a binding mechanism. 715 Dec 34

We report a study of the relative reactivity of the common amino acids and of their residues in lysozyme with osmium tetroxide, the osmium tetroxide-pyridine reagent, and with the oxo-osmium(VI)-pyridine reagent. With free amino acids, the osmium(VIII) reagents are most reactive with Met, Cys, His, Thr, Ser, Trp, Lys, and Pro; the osmium(VI) reagent only reacts significantly with His, Met, Cys, Thr, and Ser. In lysozyme, only Cys, Met, and Trp react extensively with the osmium(VIII) reagents; with the osmium(VI) reagent, Cys and Met are most reactive. We also note evidence both for cross-linking of proteins and for peptide bond cleavage, which appears to have considerable specificity for tryptophanyl residues.
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PMID:Reaction of osmium reagents with amino acids and proteins. Reactivity of amino acid residues and peptide bond cleavage. 730 53

Three inducible bacteriolytic proteins, designated P7, P9A and P9B, from the hemolymph of immunized pupae of the giant silk moth Hyalophora cecropia have been purified using a two-step procedure with cation-exchange chromatography. Purified protein P7 has a molecular weight of 15000 and its amino acid composition shows a great similarity to that of the lysozyme from the wax moth Galleria mellonella. Moreover, heat stability, pH-rate profile and bacteriolytic specificity also indicate that protein P7 is a lysozyme. The other purified proteins, P9A and P9B, are highly potent against Escherichia coli and some other gram-negative bacteria. The amino acid compositions of proteins P9A and P9B are very similar, although the contents of glutamic acid and methionine were different. The molecular weights of these very basic proteins are around 7000. The P9 proteins are heat stable; their activities were retained after 30 min incubation at 100 degrees C. Both forms of protein P9 clearly differ from the lysozyme class of enzymes and they may represent a new type of bacteriolytic protein.
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PMID:Insect immunity. Purification and properties of three inducible bactericidal proteins from hemolymph of immunized pupae of Hyalophora cecropia. 734 Dec 34


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