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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have detected a protein phosphatase activity in soluble extracts from the halophilic archaeon Haloferax volcanii. This activity was markedly stimulated by the divalent metal ions Mn2+ and Cd2+. It dephosphorylated phosphoseryl residues in casein, mixed histones, and phosphorylase a, but not phosphotyrosyl residues in reduced, carboxyamidomethylated and maleylated lysozyme. This protein phosphatase activity was inhibited by NaF, Zn2+, vanadate, molybdate, inorganic phosphate, inorganic pyrophosphate, or p-nitrophenyl phosphate, or by treatment with diethylpyrocarbonate. Activity was unaffected by other potential inhibitors or activators such as polyamines, heparin, cyclic nucleotides, Ca2+/calmodulin, tartrate, tetramisole, okadaic acid, microcystin LR, or sulfhydryl-modifying agents. The functional similarities between this protein-serine phosphatase and that previously identified in another archaeon, the extreme acidothermophile Sulfolobus solfataricus, suggest the existence of a family of divalent metal ion-stimulated protein-serine phosphatases of extremely ancient origin in the Archaea.
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PMID:A protein-serine phosphatase from the halophilic archaeon Haloferax volcanii. 839 5

The Ca2+-ATPase inhibitor thapsigargin (TG) activates bivalent-cation early in human neutrophils via depletion of intracellular Ca2+ stores bu little is known about the underlying mechanism and the functional role of TG-induced cation entry. We studied the effects of TG on univalent- and bivalent cation entry, lysozyme release and superoxide-anion (O2-) formation in human neutrophils. TG, like the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), stimulated entry of Ca2+, Mn2+, Ba2+, Sr2+ and Na+ in a 1-{beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl}-1H-imidazole hydrochloride (SK&F 96365)- and Gd3+-sensitive manner. The inhibitors of protein phosphates 1/2A, calyculin A and okadaic acid, diminished TG-induced cation influxes, whereas the inhibitors of protein phosphatase 2B, cyclosporin A and FK-506, were potentiators. Pertussis toxin (PTX) partially inhibited the effects of TG on Ca2+ and Mn2+ entry. TG and fMLP activated inward currents with a linear current-voltage relationship and a reversal potential at about 0 mV. TG activated lysozyme release and potentiated fMLP-induced O2- formation. TG-induced lysozyme release was inhibited by SK&F 96365, PTX and the removal of extracellular Ca2+ or Na+. Our data show that TG activates a non-selective and SK&F 96365- and Gd3+-sensitive cation entry pathway and is a partial secretagogue. TG-stimulated cation entry involves PTX-sensitive G-proteins and protein phosphatases, with protein phosphatases 1/2A and 2B playing opposite roles.
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PMID:Thapsigargin activates univalent- and bivalent-cation entry in human neutrophils by a SK&F I3 96365- and Gd3+-sensitive pathway and is a partial secretagogue: involvement of pertussis-toxin-sensitive G-proteins and protein phosphatases 1/2A and 2B in the signal-transduction pathway. 867 85

The mannose-specific lectin, concanavalin A (ConA), activates Ca2+ entry in human neutrophils by an as yet poorly defined mechanism. The question of whether the sugar specificity of lectins influences signal transduction is unresolved too. Therefore, we studied the effects of ConA in comparison to those of the beta-galactoside-specific lectin, mistletoe lectin I (MLI), on cation entry and exocytosis in human neutrophils. ConA- and MLI-activated influx of Ca2+, Mn2+, Ba2+, Sr2+, and Na+. Lectin-induced cation influxes were inhibited by 1-(beta-[3-(4-methoxyphenyl)propoxy]-4-methoxy-phenethyl) -1H-imidazole hydrochloride (SK&F 96365) and Gd3+. There were differences in the effectiveness of lectins to activate cation entry and of SK&F 96365, Gd3+, and modulators of protein phosphorylation to block entry. MLI but not ConA inhibited thapsigargin-induced Ca2+ entry. Under whole-cell voltage-clamp conditions, MLI activated an inward current that was substantially reduced by removal of extracellular Na+. ConA and MLI synergistically activated Ca2+ entry and lysozyme release. SK&F 96365 and removal of extracellular Ca2+ and Na+ partially inhibited exocytosis. Our data show the following: (1) ConA and MLI activate monovalent and divalent cation entry in human neutrophils by a SK&F 96365- and Gd3+-sensitive pathway, presumably nonselective cation channels. (2) Ca2+ and Na+ entry are involved in the activation of exocytosis by lectins. (3) The differential and/or synergistic effects of ConA and MLI on cation entry and exocytosis may be attributable to mannose- and beta-galactoside-specific activation of signal transduction pathways, i.e., activation of multiple and differentially regulated subtypes of nonselective cation channels.
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PMID:Concanavalin A and mistletoe lectin I differentially activate cation entry and exocytosis in human neutrophils: lectins may activate multiple subtypes of cation channels. 883 Jul 91

The serum lysozyme level of workers engaged in the production of iron-manganese alloys was observed. The lysozyme level was statistically significantly increased compared with the control group. There was no evidence with age and years of work.
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PMID:[The influence of occupational exposure to manganese on levels of serum lysozyme]. 883 28

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

The exudate of fully germinated spores of Clostridium perfringens S40 in 0.15 M KCI-50 mM potassium phosphate (pH 7.0) was found to contain another spore-lytic enzyme in addition to the germination-specific amidase previously characterized (S. Miyata, R. Moriyama, N. Miyahara, and S. Makino, Microbiology 141:2643-2650, 1995). The lytic enzyme was purified to homogeneity by anion-exchange chromatography and shown to be a muramidase which requires divalent cations (Ca2+, Mg2+, or Mn2+) for its activity. The enzyme was inactivated by sulfhydryl reagents, and sodium thioglycolate reversed the inactivation by Hg2+. The muramidase hydrolyzed isolated spore cortical fragments from a variety of wild-type organisms but had minimal activity on decoated spores and isolated cell walls. However, the enzyme was not capable of digesting isolated cortical fragments from spores of Bacillus subtilis ADD1, which lacks muramic acid delta-lactam in its cortical peptidoglycan. This indicates that the enzyme recognizes the delta-lactam residue peculiar to spore peptidoglycan, suggesting an involvement of the enzyme in spore germination. Immunochemical studies indicated that the muramidase in its mature form is localized on the exterior of the cortex layer in the dormant spore. A gene encoding the muramidase, sleM, was cloned into Escherichia coli, and the nucleotide sequence was determined. The gene encoded a protein of 321 amino acids with a deduced molecular weight of 36,358. The deduced amino acid sequence of the sleM gene indicated that the enzyme is produced in a mature form. It was suggested that the muramidase belongs to a separate group within the lysozyme family typified by the fungus Chalaropsis lysozyme. A possible mechanism for cortex degradation in C. perfringens S40 spores is discussed.
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PMID:Molecular characterization of a germination-specific muramidase from Clostridium perfringens S40 spores and nucleotide sequence of the corresponding gene. 915 Feb 12

In human neutrophils, the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenalalanine (fMLP), the Ca(2+)-ATPase inhibitor, thapsigargin, and the lectins, concanavalin A (Con A) and mistletoe lectin I (ML I), stimulate the entry of Ca2+ and Na+ with subsequent activation of exocytosis and superoxide anion (O2-) formation. We studied the role of actin in neutrophil activation. The actin filament-disrupting substances, dihydrocytochalasin B (dhCB) and botulinum C2 toxin (C2 toxin) potentiated fMLP- and lectin-stimulated Ca(2+)- and Na+ entry. Lectin-induced Mn2+ entry was enhanced by actin disruption, whereas fMLP-triggered Mn2+ entry was unaffected. dhCB and C2 toxin inhibited fMLP- and lectin-stimulated Ba2+ influx. The actin disrupters also inhibited fMLP- and ML I-induced Sr2+ influx, whereas Con A-stimulated Sr2+ entry was not influenced by dhCB and C2 toxin. Thapsigargin-stimulated cation entry was not altered by actin disruption. DhCB and botulinum C2 toxin potentiated lysozyme release induced by all four stimuli. Con A and ML I per se activated O2- formation only in the presence and not in the absence of dhCB. Con A potentiated the stimulatory effects of ML I on O2- formation in the presence of dhCB and primed neutrophils to respond to ML I in the absence of dhCB. Our data indicate the following: (1) dhCB and C2 toxin uncover the existence of multiple cation entry pathways in neutrophils; (2) actin disruption facilitates exocytosis and O2- formation by enhancement of Ca(2+)- and Na+ entry and by altering the function of proteins involved in activation of secretion and O2- formation; and (3) Con A and ML I, which possess different sugar specificities, activate different signaling pathways in neutrophils.
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PMID:Complex regulation of human neutrophil activation by actin filaments: dihydrocytochalasin B and botulinum C2 toxin uncover the existence of multiple cation entry pathways. 920 Dec 61

The chromatographic selectivity of the immobilized chelate system, 1,4,7-triazocyclononane (tacn), complexed with the borderline metal ions Cu2+, Cr3+, Mn2+, Co2+, Zn2+, and Ni2+ has been investigated with hen egg white lysozyme, horse heart cytochrome c, and horse skeletal muscle myoglobin, as well as proteins present in partially fractionated preparations of human plasma. The effects of ionic strength and pH of the loading and elution buffers on protein selectivities of these new immobilized metal ion affinity chromatographic (IMAC) systems have been examined. The results confirm that immobilized Mn;pl-tacn sorbents exhibit a novel type of IMAC behavior with proteins. In particular, the chromatographic properties of these immobilized M(n+)-tacn ligand systems were significantly different compared to the IMAC behavior observed with other types of immobilized tri- and tetradentate chelating ligands, such as iminodiacetic acid, O-phosphoserine, or nitrilotriacetic acid, when complexed with borderline metal ions. The experimental results have consequently been evaluated in terms of the additional contributions to the interactive processes mediated by effects other than solely the conventional lone pair Lewis soft acid-Lewis soft base coordination interactions, typically found for the IMAC of proteins with borderline and soft metal ions, such as Cu2+ or Ni2+.
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PMID:Protein selectivity with immobilized metal ion-tacn sorbents: chromatographic studies with human serum proteins and several other globular proteins. 944 41

A pea (Pisum sativum L.) nuclear enzyme with protein tyrosine phosphatase activity has been partially purified and characterized. The enzyme has a molecular mass of 90 kD as judged by molecular sieve column chromatography and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Like animal protein tyrosine phosphatases it can be inhibited by low concentrations of molybdate and vanadate. It is also inhibited by heparin and spermine but not by either the acid phosphatase inhibitors citrate and tartrate or the protein serine/threonine phosphatase inhibitor okadaic acid. The enzyme does not require Ca2+, Mg2+, or Mn2+ for its activity but is stimulated by ethylenediaminetetraacetate and by ethyleneglycolbis(beta-aminoethyl ether)-N,N'-tetraacetic acid. It dephosphorylates phosphotyrosine residues on the four different 32P-tyrosine-labeled peptides tested but not the phosphoserine/threonine residues on casein and histone. Like some animal protein tyrosine phosphatases, it has a variable pH optimum depending on the substrate used: the optimum is 5.5 when the substrate is [32P]tyrosine-labeled lysozyme, but it is 7.0 when the substrate is [32P]tyrosine-labeled poly(glutamic acid, tyrosine). It has a Km of 4 microM when the lysozyme protein is used as a substrate.
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PMID:Partial purification and characterization of an enzyme from pea nuclei with protein tyrosine phosphatase activity. 1153 62

In a previous study, we used the genome of serogroup B Meningococcus to identify novel vaccine candidates. One of these molecules, GNA33, is well conserved among Meningococcus B strains, other Meningococcus serogroups and Gonococcus and induces bactericidal antibodies as a result of being a mimetic antigen of the PorA epitope P1.2. GNA33 encodes a 48-kDa lipoprotein that is 34.5% identical with membrane-bound lytic transglycosylase A (MltA) from Escherichia coli. In this study, we expressed GNA33, i.e. Meningococcus MltA, as a lipoprotein in E. coli. The lipoprotein nature of recombinant MltA was demonstrated by incorporation of [3H]palmitate. MltA lipoprotein was purified to homogeneity from E. coli membranes by cation-exchange chromatography. Muramidase activity was confirmed when MltA was shown to degrade insoluble murein sacculi and unsubstituted glycan strands. HPLC analysis demonstrated the formation of 1,6-anhydrodisaccharide tripeptide and tetrapeptide reaction products, confirming that the protein is a lytic transglycosylase. Optimal muramidase activity was observed at pH 5.5 and 37 degrees C and enhanced by Mg2+, Mn2+ and Ca2+. The addition of Ni2+ and EDTA had no significant effect on activity, whereas Zn2+ inhibited activity. Triton X-100 stimulated activity 5.1-fold. Affinity chromatography indicated that MltA interacts with penicillin-binding protein 2 from Meningococcus B, and, like MltA from E. coli, may form part of a multienzyme complex.
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PMID:GNA33 from Neisseria meningitidis serogroup B encodes a membrane-bound lytic transglycosylase (MltA). 1215 69


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