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)

Urinary proteins from human leukemic patients have been found to alter quantitatively macromolecular synthesis in primary mouse bone marrow cultures. Urinary protein-stimulated incorporation of [3H]uridine into RNA was found after 1 day of culture. Increased levels of adenine phosphoribosyltransferase and lysozyme were demonstrable at 3 and 5 days, respectively, with urinary protein-supplemented cultures. The incorporation of 3H-labeled deoxynucleosides into DNA was higher in the presence of urinary proteins after 2 days of culture. The rate of incorporation of [3H]deoxyuridine into DNA was strongly inhibited by 10(-5) M Methotrexate and 10(-6) M 5-fluorodeoxyuridine, however, the effect of urinary proteins on incorporation of [3H]uridine into RNA and lysozyme accumulation were not inhibited. Urinary proteins also stimulated the formation of "colonies" (groups of at least 30 cells) in media containing methylcellulose. This latter phenomenon was also not inhibited by 10(-5) M Methotrexate or 10(-6) M 5-fluorodeoxyuridine. The results of these studies are consistent with the postulate that in the presence of human urinary proteins, mouse bone marrow cells in culture proceed to a phenotype characteristic of circulating peripheral white cells.
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PMID:Effects of urinary proteins from certain leukemics upon macromolecular synthesis and enzyme levels in bone marrow cultures. 12 96

Two enzyme activities involved in the biosynthesis of peptidoglycan in Micrococcus luteus (sodonensis), a transglycosidase and a phosphodiesterase, have been demonstrated in isolated membrane preparations. The transglycosidase activity promotes the in vitro synthesis of an uncross-bridged peptidoglycan that is completely susceptible to lysozyme. This in vitro-synthesized peptidoglycan consists of 76% "soluble" and 24% "insoluble" material. The soluble peptidoglycan is primarily a single low-molecular-weight species of approximately 20 disaccharide peptide units. "Insoluble" peptidoglycan, which likely represents newly synthesized material incorporated into an existing cell wall, was solubilized by butanol extraction, and the two were compared. The phosphodiesterase activity demonstrated in this system cleaves uridine diphosphate-N-acetylmuramyl-L-alanyl-D-isoglutamyl-L-lysyl-D-alanyl-D-alanine to yield N-acetylmuramyl-L-alanyl-D-isoglutamyl-L-lysyl-D-alanyl-D-alanine plus uridine 5'-monophosphate plus inorganic phosphate. This phosphodiesterase activity, not detected under normal transglycosidase assay conditions, is a recycling mechanism and acts indirectly through formation and subsequent cleavage of a lipid-linked intermediate.
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PMID:Peptidoglycan biosynthesis in Micrococcus luteus (sodonensis): transglycosidase and phosphodiesterase activities in membrane preparations. 17 77

In vitro and "in situ" assays have been developed to test the carbamyl phosphate synthetase (CPSase) activity of a series of pyrimidine-requiring mutants of Bacillus subtilis. The enzyme has been shown to be highly unstable, and was successfully extracted only in the presence of 10% glycerol and 1 mM dithiothreitol (Cleland's reagent). It loses activity rapidly when sonicated or when treated with lysozyme. Genetic studies, using mutants, indicate that B. subtilis may possess two CPSases. This possibility and its physiological consequences were probed enzymatically. CPSase activity has been shown to undergo inhibition by both uridine triphosphate and dihydroorotate; activation has been demonstrated in response to phosphoribosyl pyrophosphate (PRPP) and (to a lesser extent) ornithine.
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PMID:Carbamyl phosphate synthesis in Bacillus subtilis. 23 5

Human peripheral blood monocytes were maintained in in vitro culture for periods up to 4 months using a non-human serum source. Monocytes were cultured in Dulbecco's modified Eagle's medium buffered with 20 mM HEPES and containing 10% horse serum and 10% foetal calf serum. The metabolic and morphological changes which occur in vitro were investigated using microtitre, Linbro and T 25 cultures. During culture, monocytes increased in size, had increased membrane activity as visualized by SEM, and differentiated into a morphologically heterogeneous population of fusiform and epithelioid shapes. These cell types retained the ability to phagocytose E glut and EA and to rosette with EA and EAC. Larger giant polynucleated cells were also observed during culture; many of these lacked the ability to bind or phagocytose inert or antibody-coated erythrocytes. Increases in lysozyme release and acid phosphatase activity also occurred during culture. Cultured monocytes exhibited characteristic profiles of leucine and uridine uptake with maximal activity observed by 5 days of culture. There was no detectable uptake of thymidine. Detailed analysis of regulatory processes involved in monocyte growth and differentiation could be performed with this in vitro system.
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PMID:Long-term human peripheral blood monocyte cultures: establishment, metabolism and morphology of primary human monocyte-macrophage cell cultures. 38 89

A mutant of Escherichia coli is described whose cells show a spherical or irregular morphology, associated with leakage of beta-galactosidase and other intracellular proteins. The expression of the morphologic abnormality is most marked when the mutant is grown in rich media and is suppressed by D-alamine, D-serine, D-glutamate, or glycine supplementation. D-Alanine is the most effective amino acid supplement, half maximally supressing this anomalous property at a concentration of 75 mug/ml, as measured by the reduction in beta-galactosidase released from the cells. The mutant is more sensitive to penicillin G, D-methionine, and D-valine and it is relatively resistant to lysozyme. These phenotypic abnormalities are likewise corrected by the above supplementations. The relative rates of peptidoglycan synthesis in mutant and parent, grown under restrictive conditions, were measured both in vivo and in vitro by rates of incorporation of L-[14-D]alanine and uridine-5'-diphosphate-N-acetyl-D-[1-15C-A1-glucosamine, respectively. There is not metabolic block in the biosynthesis of uridine-5'-diphosphate-N-acetyl-muramyl-pentapeptide as shown by enzymic analysis and the lack of accumulation of uridine-5'-diphosphate-N-acetylmuramyl-peptide precursors. These preliminary studies suggest that the mutant possesses a defect in the biosynthesis of peptidoglycan although the exact lesion has not yet been established.
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PMID:D-Alanine-requiring cell wall mutant of Escherichia coli. 109 98

The poliovirus nonstructural proteins 2B, 2C, 2C3A, 2C3AB, 3A, and 3AB have been cloned and efficiently expressed in Escherichia coli cells. Each individual protein, or combinations of some of them, were cloned using polymerase chain reaction techniques and correspond to the genuine poliovirus protein plus an additional methionine. The system used to express them uses pET vectors containing the promoter of gene 10 of phage T7. Expression of protein 2C in BL21 (DE3) pLysS cells, which express the T7 lysozyme, is not toxic, and the bacteria synthesize this protein for several hours after induction. In contrast, the expression of proteins 2B, 3A, or 3AB is not tolerated by BL21 (DE3) pLysS cells which could make them only for a limited period of time. Protein 3AB was particularly toxic and induced a rapid lysis of the recombinant clone after its induction with isopropyl-1-thio-beta-D-galactopyranoside alone or with both isopropyl-1-thio-beta-D-galactopyranoside and rifampicin. Further analyses showed that 3AB induced profound modifications in membrane permeability to o-nitrophenyl-beta-D-galactopyranoside, labeled uridine, and nonpermeant translation inhibitors. Cloning and expression of proteins 2B, 3A, and 3AB in BL21 (DE3) cells that do not contain the T7 lysozyme lead to a more sustained expression of these proteins without detectable cell lysis. Changes in permeability to low molecular weight compounds such as radioactive uridine, o-nitrophenyl-beta-D-galactopyranoside, and hygromycin B readily appeared upon induction of 2B, 3A, and 3AB. Our results indicate that the poliovirus nonstructural polypeptides 2B and 3A (or 3AB) are lytic for the bacteria. In fact, both proteins 2B and 3A contain hydrophobic domains in a potential amphipathic helix; this is one characteristic shared with a number of membrane-active peptides.
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PMID:Expression of poliovirus nonstructural proteins in Escherichia coli cells. Modification of membrane permeability induced by 2B and 3A. 132 9

Foamy alveolar macrophages (FAM) are observed in lungs injured by Bleomycin (BLM), but their relation to pulmonary fibrosis is not clearly understood. We purified FAM from BLM-instilled rat lungs by density gradient centrifugation on Percoll, and studied the effect of FAM on pulmonary fibrosis. The cells lavaged from the rat lungs 14 days after the administration of BLM (B) or saline (S), were applied on Percoll. After centrifugation, the cells layered on each interface were collected and named as SI, SII, SIII, and BI, BII, BIII in order of gravity. The BI layer included 8.5% of unfractionated cells (U). These BI cells were viable (88%), significantly larger than the others, nonspecific esterase positive cells, and included much ferritin and lysozyme, and were morphologically identified as alveolar macrophages (AM). Therefore, we called the BI cells FAM. We estimated the capacity of FAM (2.5 X 10(5] to synthesize DNA (3H-thymidine uptake) and RNA (3H-uridine uptake), and the activities of silica-stimulated FAM to cause proliferation of mouse thymocytes (IL-1 activity) and rat lung fibroblasts (FP activity), and to produce PGE2. FAM has a lower mitogenic activity but did not have been protein synthetic activity as compared with the others. Silica-stimulated FAM released less IL-1 than BII or BIII, and induced less fibroblast growth than BII, but induced as much as BIII, possibly because of the increased capacity of BIII cells to produce PGE2, which is known to inhibit fibroblast growth. In this way, FAM were considered to be "already activated" rather than "highly activated" cells, but the presence of FAM suggested that smaller or denser AM might receive bleomycin stimulation and release fibrogenic mediators (IL-1 or MDGF) into the alveolar spaces during FAM formation, and that AM might participate in the fibrogenic responses.
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PMID:[The effect of foamy alveolar macrophages presented in bleomycin-injured rat lungs in pulmonary fibrosis]. 247 35

1. Rabbit neutrophils were permeabilized by treatment with Sendai virus. This was monitored by fluorescence measurement of the formation of the adduct of deoxyribonucleic acid (DNA) with ethidium bromide. 2. On addition of Ca2+, buffered (with EGTA) in the micromolar concentration range to the permeabilized cells, secretion of beta-glucuronidase (marker of azurophilic granules) and lysozyme (marker of specific granules) occurs. Lactate dehydrogenase (cytosol marker) is retained. Half-maximal secretion of beta-glucuronidase occurs at approximately pCa 6.3; lysozyme secretion occurs at approximately pCa 6.6. 3. Secretion is dependent on the provision of nucleoside triphosphates to the permeabilized cells. There is an absolute requirement for adenosine 5'-triphosphate (ATP) for the secretion of lysozyme, but beta-glucuronidase secretion can be partly supported by other nucleoside triphosphates in the order guanosine 5'-triphosphate (GTP) greater than uridine 5'-triphosphate (UTP) = xanthosine 5'-triphosphate (XTP) greater than cytidine 5'-triphosphate (CTP). 4. Secretion from both granules is complete within 10 min of adding Ca2+ to the permeabilized cells. There is a delay before commencement of beta-glucuronidase secretion of approximately half a minute; the secretion of lysozyme has no measurable delay.
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PMID:Differential control of azurophilic and specific granule exocytosis in Sendai-virus-permeabilized rabbit neutrophils. 282 Dec 33

Chicken erythrocyte histone H5 has been suggested repeatedly to be a general suppressor of transcription and replication. Therefore, the biological functions of H5 were investigated and compared with those of H1 (H1a + H1b) by microinjection of the purified proteins into proliferating L6 rat myoblasts. By pulse-labelling of the injected cells with [3H]uridine and [3H]thymidine it was shown that H5 blocked both transcription and replication substantially, and that the chromatin of the injected cells became densely compacted. H1 also suppressed these functions, but to a much lesser degree. The effects were specific and not caused by change in intracellular pH caused by introduction of the very basic H5, or its non-specific interaction with nucleic acid, since injection of protamine or lysozyme did not affect the cells. The migration and localization of injected H5 was monitored at different times after injection by immunofluorescence, which revealed that H5 was efficiently and stably concentrated in the nucleus. The results indicate that H5 indeed might function as an inactivator of the erythroid genome in its natural environment, probably by keeping the chromatin in a very condensed state.
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PMID:Chicken histone H5 inhibits transcription and replication when introduced into proliferating cells by microinjection. 307 39

The supernatant fractions of lysates of Lactobacillus plantarum metabolize mevalonate into lipids. Adenosine triphosphate and uridine, as well as related compounds, and reduced nicotinamide adenine dinucleotide phosphate or reduced nicotinamide adenine dinucleotide stimulate this process. To obtain very active supernatant fractions, the method of lysis is modified to include polyamines during lysozyme treatment of cells and subsequent shocking with citrate buffer.
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PMID:Mevalonate metabolism in supernatant fractions of lysates of Lactobacillus plantarum. 439 96


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