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)

The cell envelope of Neisseria gonorrhoeae, colony type 4, was studied. Outer membrane was isolated by lysozyme and ethylenediaminetetraacetic acid treatment of plasmolyzed cells according to Wolf-Watz et al. (1973). The degree of purity of the membrane preparations was checked by electron microscopy. The membrane fraction obtained had a density of 1.25 g/cm(3), was rich in phospholipase A and lysophospholipase, and contained only 10% of the total membrane activity of succinate dehydrogenase and d-lactate dehydrogenase. The outer membrane protein profile after sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed at least six major proteins. The predominating protein showed a molecular weight of 35,000. The lipopolysaccharide component was characterized by gas chromatography. The carbohydrates found were galactose, glucose, and glucosamine. d-Glycero-l-manno-heptose was present in very low amounts. Lipid A contained lauric acid, stearic acid, and beta-hydroxy-myristic acid. About 20% of the fatty acids in the outer membrane was derived from lipid A. The phospholipids were characterized as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. There was no evidence for a lipoprotein anchored to the peptidoglycan. The peptidoglycan of N. gonorrhoeae was of the chemotype I. The cell envelope of N. gonorrhoeae was found to be highly permeable to gentian violet. Cell envelopes of one penicillin-resistant and two penicillin-sensitive strains were compared. Only moderate differences in fatty acid composition were found.
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PMID:Cell envelope of Neisseria gonorrhoeae: outer membrane and peptidoglycan composition of penicillin-sensitive and-resistant strains. 80 26

We report the selection and characterization of a U-937 subline which is capable of long-term growth in serum-free medium and can be induced to differentiate. The subline (U-937-1SF) can be maintained in standard RPMI-1640 medium supplemented by antibiotics only. As compared to the serum-dependent U-937 parental cell line, U-937-1SF produced lower amounts of lysozyme and elastase and had a decreased surface expression of complement receptor 1 (CD35) and myeloid antigens CDw17 and CD38. Apart from these alterations, the U-937-1SF cells appear to be morphologically, cytogenetically and phenotypically similar to the parental U-937 clone-1 cells. The capacity of U-937 clone-1 cells to undergo phorbol myristic acid (PMA)-, vitamin D3 (VitD3)- and retinoic-acid (RA)-induced differentiation was retained in the U-937-1SF cells as evidenced by the induced growth arrest, development of a monocyte/macrophage morphology and increased expression of differentiation-associated antigens, e.g. CD11b, CD11c, CD14 and CD18. The growth-inhibitory response to cytokines involved in the activation and differentiation of monocytes, IFN-gamma, TNF-alpha, IL-1 beta, IL-6 and GM-CSF, was normal. Our results suggest that the U-937-1SF subline can be used as a serum-free model system for studies on various aspects of monocyte differentiation.
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PMID:Characterization of a U-937 subline which can be induced to differentiate in serum-free medium. 172 6

The assignment of cytochrome b-558 as a component of the O2- (H2O2) -generating enzyme in guinea-pig alveolar macrophages was investigated. Guinea pig alveolar macrophages contained 76 pmol cytochrome b-558/mg protein, a value very similar to that of neutrophils. The rate of myristic acid-stimulated O2- generation by alveolar macrophages, calculated per cytochrome b-558, was only one-fourth that of neutrophils. An analysis of Percoll density gradient centrifugation profiles showed that the H2O2-generating activity of myristic acid-activated alveolar macrophages was concentrated in a single peak which was consistently associated with 5'-nucleotidase activity, a plasma membrane marker enzyme. A little H2O2-generating activity was seen with unactivated alveolar macrophages. Furthermore, the cytochrome b-558 of both myristic acid-activated and unactivated alveolar macrophages was also predominantly associated with 5'-nucleotidase activity and was found in trace amounts in a peak containing lysozyme activity, a marker of lysosome granules. Only about 6% of the cytochrome b-558 in plasma membranes from myristic acid-activated guinea-pig alveolar macrophages was anaerobically reduced by 0.5 mM NADPH, while under the same conditions about 30% of the heme protein of myristic acid-activated neutrophils was reduced. These results suggest two conclusions: firstly, that in both activated and unactivated alveolar macrophages, cytochrome b-558 is located in the plasma membrane, and the translocation of cytochrome b-558 does not occur during the activation of NADPH oxidase; and secondly, that a smaller part of cytochrome b-558 is associated with the activated NADPH oxidase of guinea pig alveolar macrophages compared with neutrophils.
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PMID:Presence of cytochrome b-558 in guinea-pig alveolar macrophages-subcellular localization and relationship with NADPH oxidase. 283 23

We have studied protein acylation in neutrophils of guinea pigs using [3H]myristate. A large number of neutrophil proteins were acylated with exogenously added myristic acid. The myristoylation was detected on 110, 77, 56, 54, 52, 42, and 37 kDa proteins. These myristoylations were stronger in peripheral blood than in peritoneal cells. Myristic acid was found to be covalently linked by an amid bond to these proteins since the proteins were resistant to boiling, chloroform/methanol and hydroxylamine treatment. Most myristoylated proteins appeared to be associated with the membrane fraction, while some of the proteins such as 77 kDa one was distributed also in the cytoplasm and translocated from the cytoplasm to the plasma membrane by stimulation. Lysozyme was myristoylated in vitro by the N-hydroxysuccinimide ester of myristic acid. The myristoylated lysozyme had an ability to be associated with phospholipid liposomes, and the membrane-associated lysozyme became a substrate of the rat brain Ca2+- and phospholipid dependent protein kinase (protein kinase C). These results indicate that myristoylation in neutrophil proteins may have an important role in metabolic regulation through their membrane association.
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PMID:Myristoylation of neutrophil proteins and their biological characteristics. 285 65

A hydrophilic enzyme, lysozyme, was myristoylated in vitro by the N-hydroxysuccinimide ester of myristic acid, and the monomyristoylated lysozyme was isolated by CM-cellulose cation-exchange column chromatography. The monomyristoylated lysozyme associated with phospholipid vesicles, whereas the association of native lysozyme was negligible. The membrane-associated monomyristoylated lysozyme was phosphorylated with partially purified rat brain Ca2+- and phospholipid-dependent protein kinase (protein kinase C) in the presence of Ca2+, phosphatidylserine and phorbolmyristate acetate. Thus, the myristoylated lysozyme became a substrate of protein kinase C through its hydrophobic association with the membrane. The present results suggest that the myristoylation of cytoplasmic proteins may have an important role in signal transduction.
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PMID:Association of a myristoylated protein with a biological membrane and its increased phosphorylation by protein kinase C. 316 45

Free endotoxin was assayed in filtered samples of E. coli suspensions submitted to the bactericidal and bacteriolytic action of 10% human serum. The Limulus amoebocyte lysate test, a passive hemolysis inhibition assay based on O antigenic specificity and the determination of 3-OH-myristic acid by mass spectrometry were used as assay methods differing from one another with regard to the part of the endotoxin macromolecule involved in the reaction. The biological activity of endotoxin was assessed in a mouse lethality test. The bactericidal and bacteriolytic action of human serum on sensitive strains of E. coli released quantities of endotoxic lipopolysaccharide (LPS) amounting to 3,000-12,000 ng/ml, for an inoculum of 1--3 x 10(8) colony-forming units. The material thus appearing in the medium was shown to react with the Limulus amoebocyte lysate, to be lethal for actinomycin D-sensitized mice and to bear O antigen, as well as 3-OH-myristic acid, a marker of lipid A. Samples of serum depleted of lysozyme by adsorption onto bentonite, and displaying a strictly bactericidal effect, released approximately 80% of the quantity of LPS appearing in the medium in a control experiment performed with untreated serum. The LPS release is therefore mainly linked to the bactericidal effect of antibody and complement. The amount of LPS released depended on the concentration of divalent cations in the medium, being reduced by an increase in the concentration of calcium and magnesium beyond the values optimal for complement activity. This effect was already observed for an increase in the concentration of divalent cations too low to alter the bactericidal or bacteriolytic effects. The significance of the release of endotoxin by complement dependent bactericidal reactions occurring in vivo is discussed.
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PMID:Release of endotoxic lipopolysaccharide by sensitive strains of Escherichia coli submitted to the bactericidal action of human serum. 704 47

The effect of some bioflavonoids on the activation of polymorphonuclear leucocyte respiration and exocytosis was examined. At 10-5-10-4 M concentration, quercetin, but not morin and rutin, was found to inhibit the concanavalin A-induced enhancement of oxygen consumption markedly, without impairing leucocyte viability and concanavalin A binding. The inhibition could be reversed by either washing the leucocytes or adding a 10-fold molar excess of 1-anilino-8-naphthalene sulphonate. Concanavalin A-dependent cell secretion of lysozyme was also totally inhibited by 30 muM quercetin. The effect of quercetin on the activation of leucocyte respiration appeared to be stimulus specific. In fact, at a concentration of the flavonoid (75 muM) which provided a 95% inhibition of the concanavalin A-induced stimulation, the respiratory activation produced by phospholipase C was inhibited by about 50% and that caused by myristic acid and by the antibiotic Br-X537A by less than 25%. These data suggest that quercetin exerts its activity at specific sites of the plasma membrane of the leucocytes, and that this compound might be used to identify the membrane domain whereon different stimuli act to originate the initial stimulatory signal.
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PMID:Inhibition by quercetin of activation of polymorphonuclear leucocyte functions. Stimulus-specific effects. 734 82

A hydrophilic enzyme, lysozyme, was myristoylated in vitro by the N-hydroxysuccinimide ester of myristic acid and three monomyristoylated lysozymes modified at a distinct position (at Lys-13, Lys-33, Lys-97) were isolated by two-step column chromatography. The relationship between membrane binding and phosphorylation by protein kinase C of these monomyristoylated lysozymes were examined using phospholipid vesicles. These three lysozymes bound to phospholipid vesicles to the same extent, whereas the binding of nonmyristoylated native lysozyme was negligible. When native and three monomyristoylated lysozymes were reacted with protein kinase C in a phosphatidylserine (PS)-containing vesicle system, phosphorylation was observed with the myristoylated lysozymes, whereas that of native lysozyme was negligible. However, a remarkable (more than sixfold) difference in the extent of phosphorylation by protein kinase C was observed among three monomyristoylated lysozymes with a different myristoylated position. These results suggest that the membrane binding of substrate protein is not sufficient for the phosphorylation by protein kinase C and the topology of the substrate protein on the membrane play a crucial role in the recognition of substrate protein by protein kinase C. These results further indicate that protein myristoylation can modulate the topology of the membrane-bound protein.
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PMID:Myristoylation of protein at a distinct position allows its phosphorylation by protein kinase C. 808 Feb 81

Hen egg white lysozyme was lipophilized with short and middle chain saturated fatty acids (caproic, capric, or myristic acid). The yield, bactericidal properties, and structural properties of lipophilized lysozymes were investigated. The yield of lipophilization of lysozyme greatly increased with the decrease in the chain length of fatty acid. Lipophilization broadened the bactericidal action of lysozyme to Gram-negative bacteria with little loss of enzymatic activity. The bactericidal activity increased in proportion to the number of bound short chain fatty acids. The thermal stability of lipophilized lysozyme decreased in proportion to the chain length and number of bound fatty acids.
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PMID:Lipophilization of lysozyme by short and middle chain fatty acids. 1069 26

About 1000 species of bacteria are present in the human intestine. Some Gram-negative bacteria such as Escherichia coli or Salmonella spp. among intestinal bacteria have lipopolysaccharide (LPS), which might induce inflammation of human intestines. Actually, LPS, especially its lipid A constituent, is toxic. Small amounts of LPS in bacteria cause inflammation of mucosa and other tissues in humans. Such bacteria may be regulated by beneficial lactic acid bacteria to maintain human health. Many lactic acid bacteria show cancer prevention activity and anti-inflammatory activity in intestines. Recently, Pediococcus pentosaceus AK-23 was isolated from fermentative vegetable pickles for neutralization of LPS. For this study, a protein for LPS neutralization was purified partly from P. pentosaceus AK-23. For this study, a protein for LPS neutralization was purified partly from P. pentosaceus AK-23, by ultrafiltration using a 300 kDa membrane and a 100 kDa membrane after cell wall digestion by lysozyme. Gel running blue native electrophoresis revealed the existence of a 217 kDa protein. The band of the protein having the ability to bind LPS on the gel was analyzed for amino acid homology. As the result, it is revealed as part of a subunit of heat shock protein (HSP). Furthermore, it displayed LPS binding or hydrophobic motifs. The protein neutralized LPS to release fatty acid as myristic acid and glucose from polysaccharide. These findings suggest that HSP in P. pentosaceus AK-23 neutralizes LPS to decompose it compising fatty acid and polysaccharide.
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PMID:Neutralization of Lipopolysaccharide by Heat Shock Protein in Pediococcus pentosaceus AK-23. 2858 86


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