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)

Exposure of human neutrophils to 5(S),12(R)-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid (leukotriene B4, LTB4) resulted in a time- and concentration- (10(-9)-10(-6) M) dependent extracellular release of granule-associated lysozyme and myeloperoxidase (MPO). Enzyme extrusion was negligible if cells were not pretreated with cytochalasin B prior to exposure to LTB4. A time-dependent deactivation of granule exocytosis was observed in neutrophils which were stimulated with LTB4 prior to contact with cytochalasin B. LTB4-induced enzyme release was markedly enhanced in the presence of extracellular calcium. Nevertheless, significant enzyme discharge occurred in the absence of extracellular calcium, and the percent of total activity released was not altered in the presence of EGTA. The calmodulin antagonist, trifluoperazine (TFP), and the intracellular calcium antagonist, 8-(N,N-diethylamino)-octyl-(3,4,5-trimethoxy)benzoate hydrochloride (TMB-8), caused a dose-related inhibition of enzyme release from LTB4-stimulated neutrophils. Degranulation was suppressed by the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), and the sulfhydryl reagents iodoacetic acid (IA) and N-ethylmaleimide (NEM). Sodium cyanide was inactive. Two inhibitors of transmethylation, 3-deazaadenosine (3-DZA) and L-homocysteine thiolactone (HCTL), alone or in combination, had no effect on LTB4-elicited degranulation. The protein synthesis inhibitor, cycloheximide, was inactive. Neutrophils pretreated with LTB4 or 5(S),12(R),20-trihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid (20-OH-LTB4, an omega-oxidation metabolite of LTB4) were desensitized to the subsequent exposure to LTB4. Cross-desensitization was also demonstrated between LTB4 and 20-OH-LTB4. The stimulus specific nature of LTB4-induced desensitization of neutrophil degranulation was demonstrated by the fact that cells exposed to 1-O-hexadecyl/octadecyl-2-O-acetyl-sn-glyceryl-3-phosphorylcholine (AGEPC) or N-formyl-methionyl-leucyl-phenylalanine (FMLP) were capable of inducing granule exocytosis from LTB4-pretreated neutrophils. Enzyme release from LTB4-treated cells was suppressed with the phospholipase inhibitor, 4-bromophenacyl bromide (4-BPB), the cyclooxygenase/lipoxygenase inhibitor, ETYA, and the 5-lipoxygenase inhibitor, U-60, 257. However, the cyclooxygenase inhibitor, flurbiprofen, exerted a weak suppressive effect on LTB4-induced degranulation.
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PMID:Activation of the human neutrophil secretory process with 5(S),12(R)-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid. 609 46

The fine specificity of murine B 10.A/SgSn (B 10.A) T cells reactive with hen egg-white lysozyme (HEL) has been studied through the use of reduced, carboxymethylated HEL, a set of peptides encompassing the entire molecule, and a set of variant lysozymes from other species. Cells were taken from the lymph nodes draining the site of immunization at the base of the tail, and were restimulated in vitro with immunogen or analogue to measure T cell reactivity. Unlike B cell reactivity, which we have shown to be mainly associated with an epitope preserved in the N-C peptide (residues 1--17, Cys6--Cys 127, 120--129) most T cell reactivity appears to be directed towards a limited number of determinants on cyanogen bromide cleavage fragment II of HEL (LII) (13--105). This was confirmed by a cell-dilution assay in which antigen-reactive units are measured; reactivity was highest to LII, intermediate to N-C, and low but significant to cyanogen bromide cleavage fragment III (LIII) (106--129). Furthermore, priming with LII is as effective as immunization with HEL and results in the same extensive cross-reactivities to variant lysozymes. Although LII reactivity predominates in the response to HEL, injection of LIII and N-C reveals sizeable reactivity to the homologous peptides and to HEL. By cross-stimulation studies, specific epitopes could be defined in certain regions of HEL. B 10.A is clearly responsive to the overlap between N-C and LII (residues 13--17), and to an epitope in the region 106--121, but is poorly responsive to the C-terminal portion (120--129). The response to 106--121 is characterized by an exquisite specificity in which as little as a single amino acid substitution (Asn for Gln) is recognized.
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PMID:Epitope specificity of the T cell proliferative response to lysozyme: proliferative T cells react predominantly to different determinants from those recognized by B cells. 615 40

Bacillus subtilis 168 has been found to possess a high-affinity transport system for N-acetyl-D-glucosamine (GlcNAC). The Km for uptake was approximately 3.7 microM GlcNAc, regardless of the nutritional background of the cells. Apparent increases in Vmax were noted when the bacteria were grown in the presence of GlcNAc. The uptake of GlcNAc by B. subtilis was highly stereoselective; D-glucose, D-glucosamine, N-acetyl-D-galactosamine, D-galactose, D-mannose, and N-acetylmuramic acid did not inhibit GlcNAc uptake. In contrast, glycerol was an effective inhibitor of [3H]GlcNAc transport and incorporation. Partial inhibition of GlcNAc uptake was observed with azide, fluoride, and cyanide anions, carbonyl cyanide-m-chlorophenyl hydrazone, methyltriphenylphosphonium bromide, N,N'-dicyclohexylcarbodiimide, gramicidin, valinomycin, monensin, and nigericin. Two anions, arsenite and iodoacetate, were potent inhibitors of the uptake of GlcNAc in B. subtilis. Results from paper chromatography showed that there was no intracellular pool of free GlcNAc and that the acetylamino sugar was probably phosphorylated during transport. A modification of the Park-Hancock cell fractionation scheme indicated that cells grown on glycerol or D-glucose incorporated [3H]GlcNAc primarily into the cell wall fraction. When GlcNAc was used as the sole carbon source, label could be demonstrated in fractions susceptible to protease and nuclease, as well as lysozyme, showing that the N-acetylamino sugar was utilized in macromolecular synthesis and energy metabolism.
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PMID:Transport and incorporation of N-acetyl-D-glucosamine in Bacillus subtilis. 617 2

The gallinaceous lysozymes are a family of antigens that are distantly related to mouse lysozyme. A T cell-dependent proliferation assay was used to characterize the spectrum of reactivities to lysozyme determinants in B10-congenic mice. Cross-reactivity studies using a panel of species variant lysozymes to stimulate lymph node cells from chicken egg white lysozyme- and ring-necked pheasant egg white lysozyme-primed B10.D2 mice indicated a preferential focusing of T cell reactivity onto a single determinant containing amino acids 113-114. These data, in conjunction with results obtained by priming with cyanogen bromide cleavage fragments of lysozymes, suggested that a site commmon to the L3 region (amino acids 106-129) of all the lysozymes tested was a preferential anchorage site for I region-encoded Ia molecules on H-2d antigen-presenting cells, leading to the limited display of a determinant containing residues 113-114. Priming with L2H (amino acids 13-105), a peptide containing the major epitopes recognized by B10. A and B10 mice, failed to stimulate any T cell proliferation by B10.D2 lymph node cells. Thus, it appears the Ia molecules in any one mouse strain attach to very few sites on lysozyme to effectively display antigenic determinants for T cell activation. This result points to a model of limited determinant selection even on a very "foreign" antigen based upon a shortage of appropriate amino acid residues usable by Ia antigen-presenting structures of a strain.
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PMID:Immunological focusing by th mouse major histocompatibility complex: mouse strains confronted with distantly related lysozymes confine their attention to very few epitopes. 618 Sep 5

A very simple, inexpensive procedure for preparing pure plasmid DNA from bacteria is described. In this method, lysozyme-induced spheroplasts are made in presence of 833 micrograms/ml of ethidium bromide which are then lysed by a mixture of Brij 58 and sodium deoxycholate, and the lysate is centrifuged at 48,000 g for 25 min whereby about 99.9% of total chromosomal DNA is pelleted. From the supernatant containing plasmid DNA, the proteins are removed by phenol extraction and the major part of RNA by CaCl2 precipitation, and finally the small amount of residual RNA is removed by RNase treatment. The average yield of pBR322 DNA from 1 liter of amplified culture by this procedure is 2 to 2.5 mg and the preparation is highly pure, containing only about 0.005% of total yield as chromosomal DNA contaminant. Moreover, the substrate activity and the transforming ability of the plasmid DNA prepared by this method remain unaffected.
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PMID:A simple procedure for large-scale preparation of pure plasmid DNA free from chromosomal DNA from bacteria. 635 82

Heterocysts isolated from Anabaena sp. strain 7120 with lysozyme plus sonication were permeabilized with the cationic detergent cetyltrimethylammonium bromide, and they then exhibited comparable acetylene reduction activity in the light and dark with an ATP-regenerating system plus dithionite. The detergent diminished the effect of H2 in enhancing acetylene reduction.
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PMID:Permeabilization of isolated heterocysts of Anabaena sp. strain 7120 with detergent. 640 90

A method for rapid purification of plasmid DNA from lactic streptococci, utilizing microliter quantities of reagents, was developed by combination of a short lysozyme-mutanolysin cell wall digestion with a modification of the Escherichia coli plasmid isolation procedure of McMaster et al. (Anal. Biochem. 109:47-54, 1980). The preparations obtained were highly enriched for covalently closed circular DNA, and the method was applicable to plasmids of at least 40 megadaltons. Centrifugation in CsCl-ethidium bromide density gradients was not required.
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PMID:Microscale method for rapid isolation of covalently closed circular plasmid DNA from group N streptococci. 642 85

Hydrolysis of the chromogenic beta-lactam nitrocefin by periplasmic beta-lactamase in intact Pseudomonas aeruginosa cells was used to assess the influence of various compounds on the permeability of the P. aeruginosa outer membrane. In addition to the five previously described outer membrane-active compounds EDTA, polymyxin B, gentamicin, poly-L-lysine, and Tris, seven other compounds were shown to increase outer membrane permeability to nitrocefin by 14- to 63-fold. These other compounds included poly-L-ornithine, neomycin, cetyltrimethylammonium bromide, nitrilotriacetate, L-ascorbate, and acetylsalicylate. In each case, Mg2+ ions antagonized, to different extents, the enhancement of outer membrane permeability. The same compounds increased the permeability of the outer membrane to the protein lysozyme and to the hydrophobic fluorescent probe 1-N-phenylnaphthylamine, although L-ascorbate and acetylsalicylate showed only very weak enhancement of uptake in these assays. In this report, we discuss the possibility that these compounds act at a common outer membrane site at which divalent cations noncovalently cross-bridge adjacent lipopolysaccharide molecules.
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PMID:Compounds which increase the permeability of the Pseudomonas aeruginosa outer membrane. 643 88

The aim of this work was to study the influence of bacterial cell concentrations and inorganic anions on lysis of Streptococcus mutans BHT by human salivary lysozyme (HSL). HSL was partly purified from saliva by ion exchange chromatography. The bacteria were grown in a synthetic medium containing 3H-thymidine to monitor DNA release. The experiments demonstrated that release of 3H-thymidine was dependent on the bacterial cell concentration and an apparent Km-value corresponding to approximately 2.9 X 10(8) cells/ml was calculated. The influence of I-, Br-, Cl-, F-, HCO3- and SCN- on bacteriolysis was studied. All anions tested were slightly inhibitory on the action of HSL. The inhibition varied from 7 to 76% depending on the ion and ionic strength. The order of addition of HSL and sodium chloride caused different lytic responses. This was reflected by the amount of HSL adsorbed by the bacteria.
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PMID:Influence of bacterial cell concentration and inorganic anions on lysis of Streptococcus mutans BHT by salivary lysozyme. 659 37

Binding of lysozyme with cetyltrimethylammonium bromide (CTAB) and dodecyl-trimethylammonium bromide (DTAB) at various detergent concentrations and pH was studied at 25 degrees C by equilibrium dialysis technique. In the case of CTAB, binding isotherms at pH 5.0, 7.0, and 9.0 show cooperative binding at all the concentrations of the detergent and the binding ratios increase with pH. Cooperative binding is also shown by DTAB at all the concentrations and pH, but the binding ratios are lower compared to CTAB. The Gibb's free energy change calculated on the basis of Wyman's binding potential concept increases with pH, indicating increased binding strength of CTAB at higher pH. The UV difference spectra of CTAB and DTAB with lysozyme and its model compounds such as L-Trp, L-Tyr X HCI and L-Phe show two peaks at 297 nm and 250 nm at pH 9.0 indicating the possible involvement of tryptophans as the binding sites along with the carboxylate anion or the phenolic group of a tyrosine on lysozyme. The effect of higher ionic strength on the binding of CTAB with lysozyme at pH 9.0 is evidenced by lower binding ratios and decreased intensities of the UV difference bands, thus indicating the involvement of electrostatic interactions. However, the hydrophobic interactions between the detergents and the aromatic amino acid residues in lysozyme contribute more to the binding strength. The binding of these cationic detergents by lysozyme induces conformational changes in the enzyme. They are followed by the circular dichroism (CD) technique which shows a decrease in the aromatic bands in the 320-250 nm region.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interaction of cationic detergents, cetyl- and dodecyl-trimethylammonium bromides, with lysozyme. 671 7


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