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)

Lysozyme digestion and sonication of sodium dodecyl sulfate (SDS)-purified Klebsiella aerogenes murein sacculi resulted in the quantitative release of both subunits of nitrate reductase, as well as a number of other cytoplasmic membrane polypeptides (5.2%, by weight, of the total membrane proteins). Similar results were obtained after lysozyme digestion of SDS-prepared peptidoglycan fragments, which excluded the phenomenon of simple trapping of the polypeptides by the surrounding peptidoglycan matrix. About 28% of membrane-bound nitrate reductase appears to be tightly associated with the peptidoglycan. Additional evidence for this association was demonstrated by positive immunogold labeling of SDS-murein sacculi and thin sections of plasmolyzed bacteria. Qualitative amino acid analysis of trypsin-treated sacculi, a tryptic product of holo-nitrate reductase, and amino- and carboxypeptidase digests of both nitrate reductase subunits indicated the possible existence of a terminal anchoring peptide containing the following amino acids: (Gly)n, Trp, Ser, Pro, Ile, Leu, Phe, Cys, Tyr, Asp, and Lys.
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PMID:Part of respiratory nitrate reductase of Klebsiella aerogenes is intimately associated with the peptidoglycan. 354 73

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

Light and electron microscopic examination of cartilage canals in 39 infants (from fetuses to 2 years of age) revealed the presence of multivacuolated cells in the connective tissue of the canals. These cells showed an irregular and electron-dense nucleus and cytoplasm; the latter was almost filled by large, irregular, membrane-bound vacuoles without or with hardly apparent content. Histochemistry revealed a weakly positive stain with periodic-acid-Schiff, oil-red-o and muramidase techniques in these cells which seem to be degenerated macrophages.
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PMID:Multivacuolated cells in human cartilage canals. 407 10

1. The effects of teichoic acids on the Mg(2+)-requirement of some membrane-bound enzymes in cell preparations from Bacillus licheniformis A.T.C.C. 9945 were examined. 2. The biosynthesis of the wall polymers poly(glycerol phosphate glucose) and poly(glycerol phosphate) by membrane-bound enzymes is strongly dependent on Mg(2+), showing maximum activity at 10-15mm-Mg(2+). 3. When the membrane is in close contact with the cell wall and membrane teichoic acid, the enzyme systems are insensitive to added Mg(2+). The membrane appears to interact preferentially with the constant concentration of Mg(2+) that is bound to the phosphate groups of teichoic acid in the wall and on the membrane. When the wall is removed by the action of lysozyme the enzymes again become dependent on an external supply of Mg(2+). 4. A membrane preparation that retained its membrane teichoic acid was still dependent on Mg(2+) in solution, but the dependence was damped so that the enzymes exhibited near-maximal activity over a much greater range of concentrations of added Mg(2+); this preparation contained Mg(2+) bound to the membrane teichoic acid. The behaviour of this preparation could be reproduced by binding membrane teichoic acid to membranes in the presence of Mg(2+). Addition of membrane teichoic acid to reaction mixtures also had a damping effect on the Mg(2+) requirement of the enzymes, since the added polymer interacted rapidly with the membrane. 5. Other phosphate polymers behaved in a qualitatively similar way to membrane teichoic acid on addition to reaction mixtures. 6. It is concluded that in whole cells the ordered array of anionic wall and membrane teichoic acids provides a constant reservoir of bound bivalent cations with which the membrane preferentially interacts. The membrane teichoic acid is the component of the system which mediates the interaction of bound cations with the membrane. The anionic polymers in the wall scavenge cations from the medium and maintain a constant environment for the membrane teichoic acid. Thus a function of wall and membrane teichoic acids is to maintain the correct ionic environment for cation-dependent membrane systems.
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PMID:The function of teichoic acids in cation control in bacterial membranes. 472 2

Two groups of mutants altered in lytic enzyme activities have been isolated from Bacillus licheniformis 6346 MH-1 by screening clones for halo production in agar plates containing cell wall conjugated with Procion brilliant red. In the first group which produced halos during colony formation, two were shown to contain three- and eightfold more muramyl-l-alanine amidase than the parent. These strains liberated amidase and intracellular alpha-glucosidase into the culture medium during exponential growth in liquid medium. Isolated walls had a normal qualitative composition and in autolysing liberated N-terminal amino acids and reducing groups. Wall preparations from the second group of mutants which did not produce halos lysed very poorly at pH 9.5, the optimal pH for amidase activity, and poorly at pH 5.5 even though they had similar endo-N-acetylglucosaminidase activities to the parent. Two of these strains that were also deficient in phosphoglucomutase had only 3 to 5% of the membrane-bound amidase activity compared with that in the parent. Cell walls of the phosphoglucomutase-deficient mutants treated with sodium dodecyl sulfate to inactivate endogenous lytic enzymes were dissolved at 10% of the rate of those from the parent by added amidase, but their sensitivities to lysozyme were similar. Those from one mutant had 10 to 20% of the amidase-binding capacity of parent walls, whereas its isolated mucopeptide was essentially inactive in this respect. The failure of these phosphoglucomutase-deficient mutants to autolyse is likely to be due to the combined effects of both low amidase activity and resistant walls. As a result, daughter cells are unable to separate and long chains are formed during exponential growth.
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PMID:Characterization of Bacillus licheniformis 6346 mutants which have altered lytic enzyme activities. 482 3

1. The distribution of ribosomal components between the soluble and membrane fractions of a preparation of exponential-phase cells of Bacillus amyloliquefaciens lysed with lysozyme in 0.05m-tris buffer, pH7.6, containing 0.01m-Mg(2+), was strongly influenced by the addition of K(+) to the buffer, in the range 0-0.1m. 2. In the absence of K(+), 37% of the ribosomal material was bound to the membrane and was not removed by repeated washing with the lysing buffer. The amount of bound material was progressively decreased on increasing the K(+) concentration to 0.1m, when only 5% of ribosomal components remained attached to the membrane. 3. About 87% of the material that remained bound to the washed membranes prepared in the absence of added K(+) was removed on suspension of the membranes in a buffer containing 0.1m-potassium chloride. 4. In the absence of K(+), washed membranes, containing no detectable ribosomal material, were able to re-attach no more than half as much material as was found associated with membranes in the same buffer immediately after lysis. 5. There was no evidence of binding of specific components to the membrane. 6. In the presence of 0.05m-tris buffer, pH7.6, maximum incorporation of amino acids into protein by B. amyloliquefaciens polyribosomes is effected in the presence of 0.01m-Mg(2+) and 0.07-0.1m-K(+), under which conditions less than 10% of the ribosomal material of a cell lysate would be membrane-bound.
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PMID:Effect of potassium ions on the attachment of polyribosomes to the membranes in lysates of exponential-phase cells of Bacillus amyloliquefaciens. 580 17

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

A case of human sympathetic ophthalmia, enucleated after surgical trauma, was studied by means of hybridoma-derived monoclonal antibodies, histochemistry, and transmission electron microscopy. The choroidal infiltrate was composed predominantly of T-lymphocytes of the suppressor/cytotoxic subset (OKT8+); only 5% of the cells were immunoglobulin-producing B-lymphocytes (kappa or lambda light chain positive), thereby explaining the well-known paucity of plasma cells in the infiltrate. The epithelioid cells and phagocytic histiocytes in the choroid were la+ and OKM1+, antigenic determinants specific for bone marrow-derived monocytes, and their cytoplasms exhibited histochemical reactivity for alpha-1-antichymotrypsin and lysozyme. Ultrastructurally, the choroidal epithelioid cells contained single melanin granules in the cytoplasm, but these were membrane-bound and frequently associated with lysosomal material, features militating against these cells being transformed choroidal melanocytes. By means of immunologic and ultrastructural analysis, the Dalen-Fuchs nodules were found to be composed of a mixture of histiocytes (la+ and OKM1+) and depigmented retinal pigment epithelial cells (la- and OKM1-); the latter cells focally formed desmosomes and displayed inclusions of lipofuscin. Scattered within the Dalen-Fuchs nodules were small numbers of T-lymphocytes of the suppressor/cytotoxic subset. We have concluded that the uveitis and retinal pigment epithelial changes are mediated by a T-cell, delayed hypersensitivity pathogenetic mechanism (cell-mediated immunity), possibly directed at surface membrane antigens that may be shared by photoreceptors, retinal pigment epithelial cells, and choroidal melanocytes.
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PMID:Human sympathetic ophthalmia. An analysis of the inflammatory infiltrate by hybridoma-monoclonal antibodies, immunochemistry, and correlative electron microscopy. 633 39

Gentle methods for minicell lysis and lysate fractionation have been elaborated: lysis by T4 lysozyme without detergents, and fractionation by equilibrium sedimentation in a metrizamide density gradient, both at low ionic strength. In the lysates of phage-lambda-infected minicells the lambda DNA, trapped at a prereplicative step [Witkiewicz, H. and Taylor, K. (1979) Biochim. Biophys. Acta 564, 31-36], appeared in two peaks of different buoyant densities: as a membrane-bound and a free lambda DNA. The covalently-closed-circular form of lambda DNA appeared exclusively in the membrane fraction. The lambda-coded proteins, synthesized in lambda-infected minicells, appeared in two major fractions: as membrane-bound and as free proteins, and in one minor fraction, bound with free lambda DNA. Neither lambda protein engaged in the initiation of DNA replication was present in the fraction of free proteins: the P-gene product was membrane-associated, and the O-gene product formed a complex with free lambda DNA. The effect of high ionic strength (KCl) and of detergents (Triton X-100 and sarcosyl) on the binding of replication proteins with lambda DNA and with the membrane was studied. The non-ionic detergent, Triton X-100 caused displacement of a part of lambda DNA from the membrane to the free lambda DNA peak; both lambda replication proteins were bound with free lambda DNA. The binding of the O protein with lambda DNA was relatively stable, but was destroyed by the ionic detergent, sarcosyl.
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PMID:Interactions between phage lambda replication proteins, lambda DNA and minicell membrane. 645 25

Xenopus oocytes were injected with several heterologous mRNAs to investigate specific message recruitment onto polysomes. When large amounts of mRNA such as ovalbumin, which is translated on membrane-bound polysomes, are injected, most of the stable message accumulates in a postpolysomal supernatant. Conversely, when similar amounts of nonmembrane-bound mRNAs such as those which code for adenovirus protein are injected, most of the messages are found in a polysome pellet. Nonpolysomal mRNAs such as zein, ovalbumin, and lysozyme can be recruited onto membrane-bound polysomes by injected rough endoplasmic reticulum (RER). Only RER, but not Golgi apparatus, plasma membrane, or salt-washed RER has such recruiting ability. In addition, the nontranslating messengers can be recruited by injecting the salt wash of the RER. Since most nontranslating mRNAs sediment to regions less than the 80 S monosome, the step at which translational regulation takes place is probably initiation rather than elongation. The mechanism by which recruitment might occur is discussed.
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PMID:The recruitment of membrane-bound mRNAs for translation in microinjected Xenopus oocytes. 668 11


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