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)

Pulmonary alveolar macrophages (PAM) are present during acute lung inflammation, yet the functional role of these cells in both the initiation and resolution of lung injury is not well defined. To better understand the relationship between PAM functional responses and the evolution of acute reversible lung injury, we examined the ability of both unstimulated and stimulated (PMA, zymosan) PAM to secrete reactive oxygen metabolites (superoxide anion O2-) and lysosomal enzymes (lysozyme, N-acetyl-B-D-glucosaminidase) at specific time points (0, 6, 12, 24, 48, and 72 h) after initiation of acute lung injury via reverse passive Arthus reaction in pathogen-free Sprague-Dawley rats. After acute lung injury, stimulated PAM produced increasing amounts of O2- compared with PAM from noninjured lungs. Maximal O2- production by PAM occurred at 24 h after lung injury, at which time a 3.5-fold and 50% increase in O2- production by PAM was observed when PAM were stimulated with PMA and zymosan, respectively. The amount of O2- generated by these cells slowly decreased during the next 48 h. Enhanced generation of O2- by PAM from injured lungs was not due to altered enzymatic activity of the O2--producing NADPH oxidase, nor was it due to an absolute increase in the NADPH oxidase in "activated" PAM. These observations suggest that increased O2- generation by PAM from injured lungs is due to enhancement of mechanisms responsible for induction of oxidase activity. In addition, a differential accumulation and secretion of lysozyme and N-acetyl-B-D-glucosaminidase activity by PAM was observed after acute lung injury.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pulmonary alveolar macrophage function during acute inflammatory lung injury. 303 76

Degradation of cell wall components of certain microbial species following phagocytosis by neutrophils and macrophages might involve the activation, by leucocyte cationic proteins, of the bacterial autolytic wall enzymes, leading to bacteriolysis. Lysozyme (a distinct cationic agent), which is the main muramidase present in leucocytes and in body fluids, might function not only as an enzyme but also as a potent activator of autolysis. Sulphated polyelectrolytes, proteolytic enzymes and oxygen radicals, which are released in inflammatory sites, might inactivate the autolytic wall enzymes, leading to the accumulation of peptidoglycan-polysaccharide complexes within macrophages. Activated macrophages are instrumental in initiating chronic inflammatory reactions. Undegraded microbial cell wall components also function as immunomodulators and as enhancers of non-specific resistance to infections and to malignancy.
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PMID:The biochemistry of bacteriolysis: paradoxes, facts and myths. 307 29

Heart lipoamide dehydrogenase, liver alcohol dehydrogenase and egg-white lysozyme are photo-oxidized in the presence of various dye sensitizers. The photodynamic process is preceded by the binding between the enzyme and the sensitizers. Among the commonly used dyes, halogenated xanthines and thiazine are effective sensitizers for the photo-inactivation of these three enzymes. Histidine residues are the primary target for the sensitized photo-oxidation that inactivates lipoamide dehydrogenase and alcohol dehydrogenase. However, the destruction of tryptophan residues is responsible for the photo-inactivation of lysozyme. The deuterium medium effect and the quenching effect by various scavengers of the potential photo-oxidative intermediates implicate the participation of the mixed type I-type II mechanism, with the involvement of singlet oxygen being of greater importance, in the photo-inactivation of the enzymes.
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PMID:Dye-sensitized photo-oxidation of enzymes. 315 81

Varying culture medium oxygen tension from one-half to twice the normal concentration did not alter adult or cord blood monocyte-derived macrophage secretion of lysozyme or total protein. Lowering oxygen tension did result in significant increases in fibronectin concentration in both adult and cord blood macrophage culture supernatants. Dexamethasone (10(-7) M) completely blocked adult macrophage but had no effect on cord blood macrophage fibronectin release in response to lowering oxygen tension. These results indicate that human macrophages selectively regulate fibronectin production in response to changes in oxygen tension in vitro.
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PMID:Culture medium oxygen tension affects fibronectin production in human adult and cord blood macrophages. 319 77

To examine the effects on protein and electrolyte reabsorption of reducing the energy supply to the proximal tubules, an inhibitor of the citric acid cycle, maleate (600 mg.kg-1), was administered to anesthetized dogs during continuous ethacrynic acid infusion. One hour after infusion, maleate reduced renal oxygen consumption from 128 +/- 3 to 48 +/- 6 mumol.min-1. Comparisons at similar GFR showed that maleate reduced bicarbonate reabsorption by 65%, chloride reabsorption by 60% and phosphate reabsorption by 90%. Tubular reabsorption of lysozyme, determined by the 'trapped-label' method, was reduced by 97%. Total protein excretion in urine increased from 0.12 to 1.0 mg.min-1 and was not associated with a significant increase in brush border and lysosome marker enzymes. However, by superimposing a carbonic anhydrase inhibitor, acetazolamide (100 mg.kg-1), electrolyte reabsorption was slightly further reduced but protein excretion increased to 2.7 mg.min-1, coincidentally with a dramatic increase in enzyme excretion: approximately 20-fold in the brush border enzymes, alanine aminopeptidase and alkaline phosphatase, and 10-fold in the lysosomal enzymes, acid phosphatase and N-acetyl-beta-glucosaminidase. Our data indicate that maleate stops protein reabsorption without signs of acute tubular damage, whereas subsequent administration of acetazolamide results in tubular desquamation and albumin leakage.
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PMID:Effect of maleate on tubular protein reabsorption in dog kidneys. 323 92

We investigated the effects of mercuric chloride on phagocytic capacity, formation of toxic oxygen species and release of lysosomal enzymes of human polymorphonuclear leukocytes (PMNL). Our results show that HgCl2 may alter these microbicidal functions of human PMNL without remarkable damage of cell viability. The phagocytic capacity was markedly depressed in a concentration-dependent manner. The formation of toxic oxygen species was also diminished by mercuric chloride when induced by phagocytosis. It was furthermore reduced when the PMNL were activated without phagocytosis by binding of IgG to Fc-receptors or by binding of phorbol myristate acetate to the membrane. In contrast, the release of the lysosomal enzyme lysozyme was enhanced in the presence of mercuric chloride, but not the release of beta-glucuronidase. These effects may lead to impaired defense against infections and possibly to inflammatory reactions in adjacent tissues induced by released lysosomal enzymes.
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PMID:Effect of mercuric chloride on microbicidal activities of human polymorphonuclear leukocytes. 339 53

Monomeric zinc tetrasulphophthalocyanine in aqueous buffer is an effective sensitizer for the photo-oxidation of amino acids and nucleic acid bases and for the photodynamic inactivation of the enzyme, lysozyme; these reactions appear to be mediated by singlet oxygen.
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PMID:Zinc tetrasulphophthalocyanine as a photodynamic sensitizer for biomolecules. 348 23

Culture medium conditioned by mononuclear leucocytes (MNL) stimulated by formalin-fixed heat-killed Staphylococcus aureus (sCM) modulated a number of neutrophil functions. The sCM inhibited the locomotion of human neutrophils in both the presence and absence of a chemotactic gradient generated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP). It also stimulated the oxygen-dependent respiratory burst as assessed by its ability to stimulate basal H2O2, superoxide and chemiluminescence production by neutrophils. Neutrophils treated with sCM also showed increased release of lysozyme but not beta-glucuronidase. In addition, the sCM-treated neutrophils showed a potentiated response to stimuli that bind surface receptors, i.e. FMLP and opsonized zymosan. The effects of sCM and either of the stimuli were synergistic. Examination of lysosomal enzyme release showed that sCM enhanced the release of lysozyme and beta-glucuronidase induced by either FMLP/cytochalasin B or zymosan. The response to phorbol myristate acetate (PMA), which bypasses the surface receptor, was also stimulated but compared poorly with the FMLP response. The sCM effects on the FMLP-induced chemiluminescence response occurred even when FMLP addition was delayed for 4 hr. Cells treated with sCM and washed retained the ability to show an enhanced FMLP response. The neutrophil-modulating activity was not produced by MNL cultured in the absence of bacteria.
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PMID:Staphylococcus aureus-stimulated human mononuclear leucocyte-conditioned medium augments the basal and stimuli-induced neutrophil respiratory burst and degranulation. 357 Mar 57

The synthesis of C3, C2, factor B (B) C1-inhibitor and lysozyme has been studied in monocytes and macrophages isolated from the synovial fluids of patients with rheumatoid arthritis. Concentrations of all 5 proteins in culture supernatants were measured by the sandwich ELISA technique. Kinetic studies showed that only lysozyme and C3 could be detected in monocyte culture supernatants on the first day of culture, whereas C2, B and C1-inhibitor were not present until the third day. In contrast all 5 proteins could be detected in the supernatants of macrophage cultures on day 1. In both monocyte and macrophage cultures synthesis of lysozyme and C1-inhibitor continued throughout the culture period, whereas synthesis of C2, B and C3 appeared to be reduced after the fifth day in culture. Quantitative studies showed that the secretion rates of lysozyme (4,700 X 10(3) molecules/cell/hr) was similar in monocytes and macrophages. Synthesis rates for all 4 complement components in monocyte cultures were less than 0.2% of that for lysozyme. Although the synthetic rates were higher in macrophages, even then they constituted less than 2% of the rate for lysozyme. Synthetic rates for complement components, but not lysozyme, were increased by BSA-anti-BSA antigen-antibody complexes and reduced by serum-treated complexes. Although the functional activity of monocyte B was similar to that for serum, the activity of monocyte C2 was 5 times that of serum C2. As C42 formed with monocyte C2 had a half-life of 13.5 min at 30 degrees C, compared with 4.5 min for the enzyme formed with serum C2, it is probable that monocyte C2 is oxidized by the oxygen products of these cells.
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PMID:Synthesis of complement components (C3, C2, B and C1-inhibitor) and lysozyme by human monocytes and macrophages. 363 67

Oxygen-17 and deuterium NMR studies of lysozyme hydration are reported for a wide range of lysozyme concentrations, and the relationship between water "activity" and water mobility in the lysozyme-water system as determined by high-field NMR is examined. In a first approximation, the effect of lysozyme activity on hydration is considered to be small because of the relatively low charge on lysozyme at pH 7 and the absence of salt in the lysozyme solutions. Correlation times are determined for tightly bound water, weakly bound water, and "multilayer" or trapped water in lysozyme at 20 degrees C. Hydration numbers are also determined for these three different water populations interacting with lysozyme. Good agreement is found between the hydration numbers determined by 17O NMR and the calculations based on the D'Arcy and Watt analysis of water sorption isotherms for proteins that considered three major water populations in hydrated lysozyme. A molecular interpretation for the three components in the D'Arcy and Watt theory of sorption isotherms is also proposed on the basis of our NMR results. Previous proton NMR spin-echo results are shown to be consistent with our findings by 17O NMR and support the view that there are at least four regions of distinct hydration behavior of lysozyme which span the whole range from solutions to solid powders.
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PMID:Oxygen-17 and deuterium nuclear magnetic resonance studies of lysozyme hydration. 370 43


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