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)

Coxiella burnetii, the etiological agent of Q fever, possesses immunomodulatory activity which positively and negatively regulates host immune responses. We wish to determine the Coxiella strain differences and the chemical nature of cellular components suppressing lymphocyte responsiveness. The bacterial components responsible for the immunomodulatory activity are associated with phase I cells. In its natural state, the phase I cell-associated, immunosuppressive complex (ISC) was resistant to chemical and enzymatic treatment. The ISC was inactivated and rendered accessible by chloroform-methanol (CM) (4:1) extraction of phase I cells which produced a CM residue (CMRI) and CM extract (CME). The suppressive components in either CMRI or CME did not induce ISC activity in the host when injected separately. Reconstitution of the CMRI with CME prior to injection produced the same pathological reactions characteristic of phase I cells. The CMRI suppressive component was sensitive to alkali, acid, periodate, lysozyme, and neuraminidase, but resistant to lipase and protease. An active component of CMRI was attached to the cell matrix by disulphide bonds. The amphipathic, lipophilic, CME suppressive component was ubiquitously distributed in procaryotes and eukaryotes because ISC activity of CMRI was regained after association with reagent-grade lipids and different CMEs. The ISC was expressed by phase I strains with smooth lipopolysaccharide (LPS) but not by phase II strains with rough LPS. Phase I heart valve strains carrying significant amounts of rough LPS did not express all of the biological properties of the ISC. The LPS molecule induced immune enhancement without immunosuppression. Thus, expression of the ISC showed strain variation and may be under genetic control. The complete details of the chemical composition and active components of the ISC should prove useful for biological-response-modification studies.
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PMID:Immune modulation by Coxiella burnetii: characterization of a phase I immunosuppressive complex differentially expressed among strains. 317 Nov 7

Transchitooligosylation from (GlcNAc)5 to the 4-position of PNP-GlcNAc was efficiently induced through lysozyme catalysis in an aqueous solution containing methanol with a high concentration. Use of the aqueous methanol system in this reaction not only guaranteed solubility of PNP-GlcNAc substrate, but also resulted in a remarkable increase in PNP-(GlcNAc)5 production. PNP-(GlcNAc)5 was substrate for lysozyme assay compared with PNP-(GlcNAc)4.
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PMID:Enzymatic synthesis of p-nitrophenyl N,N',N'',N'',N''''-pentaacetyl-beta-chitopentaoside in water-methanol system; significance as a substrate for lysozyme assay. 334 87

A murine monoclonal antibody, VM-1, which binds to basal cells of normal human epidermis, reduces the ability of human squamous cell carcinoma cells (SCL-1) derived from the skin to attach and spread on collagen by about 50% and causes cell rounding. Similar effects have been previously shown using normal human keratinocytes. The attachment of cell lines derived from human lung squamous cell carcinomas (SW1271 and SW900), melanoma A375, glioblastoma 126, and fibrosarcoma HT1080 is also inhibited by this antibody. VM-1 antibody does not bind to normal human fibroblasts, benign nevus cells, or the human B-cell-derived line 8866. VM-1 antibody inhibits the growth of SCL-1 cells in vitro as measured by cell numbers and [3H]thymidine ([3H]TdR) incorporation. It is not cytolytic in the presence of complement as measured by 51Cr release. Repeated treatment of SCL-1 cells with VM-1 antibody significantly reduces the proportion of SCL-1 cells that attach to collagen. In addition, after treatment of SCL-1 cells with VM-1 antibody, several proteins can no longer be demonstrated by gel electrophoresis of the cell-free supernatant. The VM-1 antibody effect on attachment and spreading is partially reversed by pretreatment of the collagen surface with laminin and fibronectin, but not with the carbohydrates chondroitin-6-sulfate or hyaluronic acid or with the protein lysozyme. By fluorescence staining, the antigen recognized by VM-1 antibody is membrane-bound and Triton X-100 extractable. The VM-1 antigen is excluded from Bio-Sil TSK-400 and sediments at about 10.5 S. It has a covalent molecular weight on the order of 10(6). Proteinase K digestion produces VM-1 antibody reactive fragments, assumed to be polysaccharides, with a polydisperse molecular weight distribution in the range 5000 to 30,000. The VM-1 antigen is partially lost from solution on boiling and is no longer detectable in the aqueous or organic phase after chloroform-methanol extraction. The properties of the VM-1 antigen are consistent with those of a proteoglycan involved in attachment and spreading of keratinocytes and certain tumor cells on collagen.
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PMID:Inhibition of attachment and growth of tumor cells on collagen by a monoclonal antibody. 369 49

Several methods were used to obtain serologically active materials from cultures of Micropolyspora faeni. From the results of immunodiffusion and immunoelectrophoresis tests on these materials it is suggested that preparations for the laboratory diagnosis of farmer's lung disease (FLD) should contain concentrated culture supernatant (CS) and extracts of mycelium obtained by ultrasonic treatment (MU). Although CS and MU have many serological activities in common they also possess activities unique to each.Extraction of mycelium with trichloracetic acid, boiling water or methanol yielded a product which gave simple patterns in immunodiffusion tests. The products contained little protein but were rich in carbohydrates, particularly arabinose, galactose and glucosamine. A similar material was obtained from a cell-wall preparation by treatment with lysozyme. Antibodies to the serologically active substances in these materials occurred more frequently in sera of patients with FLD than antibodies to any other M. faeni antigen.Attempts to obtain serologically active materials from spores were unsuccessful. Moreover antibodies to M. faeni could not be removed from patients' sera by absorption with partially purified spore preparations. It is suggested that the hypersensitivity in FLD arises from exposure to mycelial antigens.
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PMID:Micropolyspora faeni and farmer's lung disease. 463 26

The phospholipid mediator of anaphylaxis, platelet-activating factor (PAF) is chemotactic for polymorphonuclear leukocytes (PMN). We have examined this agent's effects on several other PMN functions. Human PMN were prepared from heparinized venous blood by Ficoll gradient. Metabolic burst was examined by measurement of O2 use and O2.- production in the presence or absence of PAF (10(-6)--10(-9) M). Unless cells were treated with cytochalasin-B (5 micrograms/ml), no significant respiratory burst was demonstrated. However, pretreatment with PAF (10(-7) M) enhanced approximately threefold the O2 utilization found when cells were subsequently stimulated with 10(-7) M FMLP. PAF also stimulated arachidonic acid metabolism in 14C-arachidonic acid-labeled PMN. Thin-layer chromatography analysis of chloroform-methanol extracts showed substances that comigrated with authentic 5-hydroxyeicosatetraenoic acid had a marked increase in radioactivity following PAF stimulation at 10(-7) M. PAF failed to stimulate release of granule enzymes, B-glucuronidase, lysozyme, or myeloperoxidase unless cytochalasin-B were added. PAF from 10(-6) M to 10(-10) M affected PMN surface responses. PMN labeled with the fluorescent dye, chlorotetracycline, showed decreased fluorescence upon addition of PAF, suggesting translocation of membrane-bound cations. Further, the rate of migration of PMN in an electric field was decreased following PAF exposure, a change consistent with reduced cell surface charge. PMN self-aggregation and adherence to endothelial cells were both influenced by PAF (10(-6) M--10(-9) M). Aggregation was markedly stimulated by the compound, and the percent PMN adhering to endothelial cell monolayers increased almost twofold in the presence of 10(-8) M PAF. Thus, PAF promotes a variety of PMN responses: enhances respiratory burst, stimulates arachidonic acid turnover, alters cell membrane cation content and surface charge, and promotes PMN self-aggregation as well as adherence to endothelial cells.
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PMID:Metabolic, membrane, and functional responses of human polymorphonuclear leukocytes to platelet-activating factor. 628 62

The high molecular weight penicillin-binding proteins (PBP(s) ) Bacillus subtilis PBPs 1, 2, and 4 and Bacillus stearothermophilus PBPs 1-4 were shown to catalyze peptidoglycan synthesis from the undecaprenol-containing lipid intermediate substrate in two assay systems. In a filter paper assay system, high levels of substrate polymerization occurred when reaction mixtures were incubated on Whatman 3MM filter paper. The pH optimum for peptidoglycan synthesis was 7.5 for B. subtilis PBPs 1, 2, and 4 and 8.5 for B. stearothermophilus PBPs 1-4. Polymerization was Mg2+-independent and was unaffected by sulfhydryl reagents. Reconstitution with membrane lipids or addition of detergent (optimal concentration, 0.1%) was necessary for synthesis to occur. Bacitracin, penicillin, and cephalothin did not affect polymerization while vancomycin, ristocetin, moenomycin, and macarbomycin were strong inhibitors. In a test tube assay system, optimal synthesis occurred either in the presence of 10% ethylene glycol, 10% glycerol, and 8% methanol or in the presence of 10% N-acetylglucosamine. The products of lysozyme digestion of the synthesized peptidoglycan were analyzed by gel filtration and paper chromatography. B. stearothermophilus PBPs 1-4 synthesized a peptidoglycan product that was 5-7% cross-linked. No evidence for cross-linking was apparent in the peptidoglycan product of B. subtilis PBPs 1, 2, and 4.
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PMID:Synthesis of peptidoglycan by high molecular weight penicillin-binding proteins of Bacillus subtilis and Bacillus stearothermophilus. 642 Apr 10

Pyridine borane has been reported as a superior reagent over a wide pH range, 5-9, for the reductive methylation of amino groups of proteins with formaldehyde [J. C. Cabacungan , A. I. Ahmed , and R. E. Feeney (1982) Anal. Biochem. 124, 272-278]. It has also been reported to reduce tryptophan to dihydrotryptophan and to inactivate lysozyme in trifluoroacetic acid [M. Kurata , Y. Kikugawa , T. Kuwae , I. Koyama , and T. Takagi (1980) Chem. Pharm . Bull 28, 2274-2275]. In the present study the specificity of pyridine borane for the two different modifications under different reaction conditions has been demonstrated, and extended to the application to the synthesis of protein containing reductively attached carbohydrates. In the acid reduction, pyridine borane selectively reduced all six tryptophans in lysozyme to dihydrotryptophan while all other amino acids remained intact. On similar treatment no cleavage of the carbohydrate moiety from chicken ovomucoid, and no losses of activity of ovomucoid or ribonuclease, two proteins devoid of tryptophan, were observed. Nearly complete methylation of the lysines of lysozyme, chicken ovomucoid, and ribonuclease was achieved with formaldehyde at pH 7.0 after 2 h at room temperature, with the retention of full activity of the protein without any destruction of tryptophan. The same chemistry was applied to covalently attach glucose and lactose to bovine serum albumin. Parameters, including pH, temperature, and methanol, that affect the reactions were investigated. Incremental additions of pyridine borane during the course of the reactions increased the rate of modification. The covalent attachment of sugar to the epsilon-amino group of lysine was demonstrated by the synthesis of N-alpha- acetylglucitollysine and comparison with acid hydrolysates of the bovine serum albumin-sugar derivatives.
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PMID:Pyridine borane as a reducing agent for proteins. 643 Jan 22

The emergence and development of chemical and thermal resistance in spores of Bacillus subtilis was examined. The chemicals studied were of the disinfectant type: glutaraldehyde, hypochlorite, hypochlorite-methanol and povidone-iodine. Growth and sporulation were followed by electron microscopy and resistance assigned to specific stages in relation to 45Ca and DPA accumulation. A sequential development of resistance was observed with thermal resistance appearing first at early Stage V corresponding to maturation of cortex and deposition of rudimentary spore coat material. Chemical resistance coincided with middle to late Stage V dependent on the chemical concerned. A progressive development of resistance was observed on prolonged incubation in sporulation medium and was affected by inclusion of lysozyme in the spore washing sequence.
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PMID:Emergence and development of resistance to antimicrobial chemicals and heat in spores of Bacillus subtilis. 643 22

As an approach to learning more about structure-forming processes in chicken egg white lysozyme, the reduced protein was studied in the presence of methanol, 2-chloroethanol, trifluoroethanol, and sodium dodecyl sulfate, at various concentrations in aqueous solution. The mixtures were subjected to gel filtration chromatography, with circular dichroism (CD) examination of the resulting polymers and monomers. Changes in CD behavior, indicating development of ordered structure, were seen to be associated only with polymer formation. Contributing to these changes were increases in beta structure as well as alpha-helix. Since the solutes studied are known as helix formers, it is suggested that studies on many proteins, carried out in the presence of these and other structure-modifying solutes, may have been complicated by formation of beta structure as well as by polymerization. The reduced monomer formed no structure in the hydrophobic environment afforded by these solutes, but only randomized further. Thus, hydrophobic interactions may be of no significance to lysozyme chain folding in its early stages. As an alternative, the long range interactions stabilized by native tertiary cross links may be critical for the transition to native secondary structure.
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PMID:Effects of structure-forming solutes on chicken egg white lysozyme after reductive cleavage of disulfide bonds. 671 8

Though extraction is probably the best method to remove interfering endogenous lysozyme activity, other methods have been suggested. Micropore filtering, 65 degrees C heat treatment and methanol precipitation, or a combination of these methods are ineffective. Heating urine samples to 85 degrees C for 30 minutes removed endogenous lysozyme activity, but unpredictably alters the responsiveness of the various drugs of abuse urine assays. It cannot be recommended for removal of endogenous lysozyme activity for all EMIT immunoassays in urine.
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PMID:Endogenous lysozyme inactivation in EMIT-dau assays. 676 11


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