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)

Sterile peritoneal exudates produced in rabbits injected with 1% glycogen contain a phospholipase A activity in a cell-free supernatant fraction that hydrolyzed a synthetic phospholipid (1,2-diacyl-sn-glycero-3-phospho-ethanolamine) and phospholipids of autoclaved Escherichia coli. This phospholipase activity (phosphatidylacylhydrolase EC 3.1.1.4) exhibited an apparent bimodal pH optimum (pH 6.0 and pH 7.5) and was Ca(2+)-dependent; Mg(2+) and monovalent cations (Na(+) and K(+)) did not substitute for Ca(2+) in the reaction; EDTA was a potent inhibitor. The phospholipase hydrolyzed 1-[1-(14)C]palmitoyl-2-acyl-sn-glycero-3-phosphoethanolamine to form only radio-active lysophosphatidylethanolamine as the product, indicating that the enzyme had phospholipase A(2) specificity. The phospholipase A(2) was purified 302-fold by two successive chromatographic steps on carboxymethyl Sephadex. Gel filtration (Sephadex G75) of the purified enzyme resulted in a single peak of biological activity with a molecular weight of approximately 14,800. The same estimate of molecular weight was obtained by SDS-polyacrylamide gel electrophoresis, which yielded a single band. Polyacrylamide gel electrophoresis of this fraction at pH 4.3 revealed a single protein band migrating beyond lysozyme, with the dye front, suggesting that this protein was more basic than lysozyme (pI 10.5). The enzymatic and physical-chemical characteristics of this soluble enzyme were remarkably similar to a recently described phospholipase A(2) of rabbit polymorphonuclear leukocytes derived from glycogen-induced peritoneal exudates. The possible origin and physiological role of this soluble enzyme are discussed.
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PMID:Isolation and characterization of a phospholipase A2 from an inflammatory exudate. 2 3

3H-FMLP, a chemotactic peptide that resembles Escherichia coli chemotactic factor, is chemotactic for PAM, binds specifically to a site on the cell, and induces the generation of superoxide radicals by the cell. Scatchard analysis revealed an equilibrium dissociation constant at 26 degrees C of 1.45 x 10(-8)M and the presence of 1.7 , 10(5) receptors per cell. Binding was not inhibited by a partially purified C5a preparation or by the neutrophil-derived CCF but was inhibited by various N-formylated peptides. The order of potency of each peptide to inhibit 3H-FMLP binding was identical to the order of potency of each peptide to induce generation of superoxide by the PAM. Only small amounts of beta-glucuronidase activity and no lysozyme were detected in the supernatant after incubation of the cells for 30 min with varying concentrations of FMLP.
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PMID:Determination of a specific receptor for formyl-methionyl-leucyl-phenylalanine on th pulmonary alveolar macrophage and its relationship to chemotaxis and superoxide production. 626 Aug 78

Granule contents from rat polymorphonuclear neutrophils were prepared by extraction with 0.2 M acetate (pH 4), dialyzed against phosphate-buffered saline (pH 7), and tested for bactericidal activity. Bactericidal assays consisted of mixing rat granule extract with 1 x 10(3) to 3 x 10(3) bacterial cells per ml at 37 degrees C for 1 h in a medium suited for bacterial growth. The granule extract demonstrated a distinctive dose-dependent bactericidal activity against outer membrane lipopolysaccharide mutants of Salmonella typhimurium LT-2, independent of added hydrogen peroxide or other active oxygen derivatives. The rough bacterial mutants showed an ordered increase in sensitivity to the rat lysosomal extracts inversely related to the length of their lipopolysaccharide carbohydrate side chains. Fractionation of the rat polymorphonuclear neutrophil granule extract with Sephadex G-100 column chromatography revealed an elution profile containing three major areas (peaks) of protein. Polyacrylamide gel electrophoresis and examination of enzymatic activity showed that these peaks contained myeloperoxidase (peak A), neutral protease (peak B), and lysozyme (peak C) activities. Also observed in peak C were cationic protein species whose cathodal electrophoretic migration was faster than that for lysozyme. Only peak C exhibited a bactericidal activity against the rough mutants of S. typhimurium LT-2 similar to that obtained for the unfractionated granule extract, with susceptibility of the bacterial mutants increasing with a progressive loss of carbohydrate residues in the lipopolysaccharide of the cell wall. The bactericidal activity of the peak C protein fraction was dose dependent. Boiling the unfractionated granule extract or peak C for 30 min had little affect on their antimicrobial activity when reacted against a deep-rough lipopolysaccharide mutant. However, trypsin pretreatment of these fractions significantly reduced their antimicrobial activity for the same mutant chemotype.
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PMID:Bactericidal activity of granule contents from rat polymorphonuclear leukocytes. 629 56

Polyacrylamide gel electrophoresis of cell-free extracts of Escherichia coli that had been grown in a medium containing 32Pi disclosed the presence of several 32P-labeled proteins. Comparison of the electrophoretic patterns obtained in the presence of carrier unlabeled purified E. coli glutamine synthetase before and after treatment with trypsin, subtilisin, or snake venom phosphodiesterase showed that most of the 32P was present in the adenylyl moieties of adenylylated glutamine synthetase. Low molecular weight 32P-labeled degradation products of glutamine synthetase were also observed in extracts prepared by treatment of cells with lysozyme but not in extracts prepared by sonic oscillation. The degradation of glutamine synthetase in lysozyme-prepared extracts is likely due to an intrinsic proteolytic activity of egg white lysozyme. Proteolysis probably occurs at the esterase site of lysozyme described by Piszkiewicz and Bruice [Piszkiewicz, D. & Bruice, T.C. (1968) Biochemistry 7, 3037-3047]. Selective carboxymethylation of lysozyme histidine-15 leads to simultaneous loss of esterase and protease activities but only to partial loss of lytic activity. In view of these findings, caution is needed in the interpretation of results obtained with extracts of cells prepared by lysozyme treatment, especially when such extracts are used to investigate the properties of proteolytic enzymes.
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PMID:A proteolytic artifact associated with the lysis of bacteria by egg white lysozyme. 634 Jan 15

The lipopolysaccharides ( LPSs ) from strains of Rhizobium leguminosarum, Rhizobium trifolii, and Rhizobium phaseoli were isolated and partially characterized by mild acid hydrolysis and by polyacrylamide gel electrophoresis. Mild acid hydrolysis results in a precipitate which can be removed by centrifugation or extraction with chloroform. The supernatant contains polysaccharides which, in general, are separated into two fractions ( LPS1 and LPS2 ) by Sephadex G-50 gel filtration chromatography. The higher-molecular-weight LPS1 fractions among the various Rhizobium strains are highly variable in composition and reflect the variability reported in the intact LPSs (R. W. Carlson and R. Lee, Plant Physiol. 71:223-228, 1983; Carlson et al., Plant Physiol. 62:912-917, 1978; Zevenhuizen et al., Arch. Microbiol. 125:1-8, 1980). The LPS1 fraction of R. leguminosarum 128C53 has a higher molecular weight than all other LPS1 fractions examined. All LPS2 fractions examined are oligosaccharides with a molecular weight of ca. 600. The major sugar component of all LPS2 oligosaccharides is uronic acid. The LPS2 compositions are similar for strains of R. leguminosarum and R. trifolii, but the LPS2 from R. phaseoli was different in that it contained glucose, a sugar not found in the other LPS2 fractions or found only in trace amounts. Polyacrylamide gel electrophoretic analysis shows that each LPS contains two banding regions, a higher-molecular-weight heterogeneous region often containing many bands and a lower-molecular-weight band. The lower-molecular-weight bands of all LPSs have the same electrophoretic mobility, which is greater than that of lysozyme. The banding pattern of the heterogeneous regions varies among the different Rhizobium strains. In the case of R. leguminosarum 128C53 LPS, the heterogeneous region of a higher molecular weight than is this region from all other Rhizobium strains examined and consists of many bands separated from one another by a small and apparently constant molecular weight interval. When the heterogeneous region of R. Leguminosarum 128C53 LPS was cut from the gel and analyzed, its composition was found to be that of the intact LPS, whereas the lower-molecular-weight band contains only sugars found in the LPS2 oligosaccharide. In the case of R. leguminosarum 128C63 and R. trifolii 0403 LPSs, the heterogeneous regions are similar and consist of several band s separated by a large-molecular-weight interval with a the major band of these heterogeneous regions having the lowest molecular weight with an electrophoretic mobility near that of beta-lactoglobulin. The heterogeneous region from R. phaseoli 127K14 consists of several bands with electrophoretic mobilities near that of beta-lactoglobulin, whereas this region from R. trifolii 162S7 shows a continuous staining region, indicating a great deal of heterogeneity. The results described in this paper are discussed with regard to the reported properties of Escherichia coli and Salmonella LPSs.
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PMID:Heterogeneity of Rhizobium lipopolysaccharides. 672 8

The protein composition of normal and pathological tears was studied by polyacrylamide-gel (disc) electrophoresis. Polyacrylamide-gel electrophoresis was shown to detect at least 14 fractions in 2-10 microliters of native tears. A comparison was made between the protein composition of normal tears and serum. The most characteristic bands in the tear-protein pattern were identified by parallel electrophoresis of tears, serum, human milk and purified egg-white lysozyme. The identified fractions were specific tear prealbumin, serum albumin, transferrin, lactoferrin and lysozyme. An unidentified major tear-protein component was also described. The tear-protein pattern was divided into six zones: (1) prealbumin zone; (2) post-albumin zone; (3) post-transferrin zone; (4) macroglobulin zone; (5) basic globulin zone; (6) prelactoferrin zone. A significant rise in the level of serum albumin and transferrin was demonstrated in tears from cases of acute catarrhal conjunctivitis. The optimal circumstances were discussed under which major and minor tear components and basic and acidic tear proteins can be determined simultaneously. Polyacrylamide-gel electrophoresis is recommended as a useful method to study the various diseases of the anterior segment of the eye.
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PMID:A polyacrylamide-gel electrophoretic study of human tear proteins. 714 Dec 35

1. Proteins in human milk and Rhesus monkey milk have been compared by FPLC gel filtration and anion exchange chromatography, SDS-Polyacrylamide gel electrophoresis, nitrogen and protein determination. 2. Mature Rhesus milk is higher in protein concentration (15-20 mg/ml) than human milk (8-9 mg/ml). 3. Non-Protein nitrogen is 6-13% in Rhesus milk but 25-30% in human milk. 4. Secretory IgA, lactoferrin, serum albumin, alpha-lactalbumin and lysozyme are present in Rhesus milk, but at a lower concentration than in human milk. 5. The casein subunit pattern is more complex in Rhesus milk compared to human milk. 6. The ratio of whey proteins to casein is similar in both milks (approximately 60/40). 7. A protein with a M(r) of 21,600 is a major component in monkey whey but is not found in human milk.
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PMID:Protein composition of rhesus monkey milk: comparison to human milk. 809 84

Gaseous CO2 was used as an antisolvent to induce the fractional precipitation of alkaline phosphatase, insulin, lysozyme, ribonuclease, trypsin, and their mixtures from dimethylsulfoxide (DMSO). Compressed CO2 was added continuously and isothermally to stationary DMSO solutions (gaseous antisolvent, GAS). Dissolution of CO2 was accompanied by a pronounced, pressure-dependent volumetric expansion of DMSO and a consequent reduction in solvent strength of DMSO towards dissolved proteins. View cell experiments were conducted to determine the pressures at which various proteins precipitate from DMSO. The solubility of each protein in CO2-expanded DMSO was different, illustrating the potential to separate and purify proteins using gaseous antisolvents. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE) was used to quantify the separation of lysozyme from ribonuclease, alkaline phosphatase from insulin, and trypsin from catalase. Lysozyme biological activity assays were also performed to determine the composition of precipitates from DMSO initially containing lysozyme and ribonuclease. SDS-PAGE characterizations suggest that the composition and purity of solid-phase precipitated from a solution containing multiple proteins may be accurately controlled through the antisolvent's pressure. Insulin, lysozyme, ribonuclease, and trypsin precipitates recovered substantial amounts of biological activity upon redissolution in aqueous media. Alkaline phosphatase, however, was irreversibly denaturated. Vapor-phase antisolvents, which are easily separated and recovered from proteins and liquid solvents upon depressurization, appear to be a reliable and effective means of selectively precipitating proteins.
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PMID:Protein purification with vapor-phase carbon dioxide. 1009 36

Several salivary proteins exhibit fungicidal activity against the opportunistic oral pathogen Candida albicans when they are tested as pure proteins in vitro. However, salivary secretions that are examined by the same assays either lack or exhibit very low candidacidal activity. Since ionic strength is known to have an inhibitory effect on the fungicidal activities of some proteins, parotid secretion was subjected to dialysis with membranes having molecular weight cutoffs (MWCOs) of 500, 1000, 10000, and 25000. Dialysis with membranes with MWCOs of >=1000 promoted fungicidal activity of parotid secretion, and this activity was dose dependent. The addition of sodium chloride to dialyzed, fungicidal parotid secretion abolished this activity, indicating that the fungicidal component was salt sensitive. Similar results were obtained with submandibular and sublingual secretions. Polyacrylamide gel electrophoresis under native and denaturing conditions was used to analyze the composition of the dialysate. Unexpectedly, proteins with MWs much lower than the nominal MWCOs of the membranes were not lost during dialysis. Among the retained proteins, the two fractions with MWs of approximately 17000 and 4000 exhibited fungicidal activity. These results are consistent with the presence of lysozyme and histatins, respectively, which may represent the major candidacidal capacity of dialyzed parotid secretion.
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PMID:Dialysis unmasks the fungicidal properties of glandular salivary secretions. 1510 79

A 4-amino-naphthalimide derived fluorophore with a triazacryptand moiety ligand was synthesized as a potassium ion (K(+)) sensor (KS1). This sensor is a monomer possessing a polymerizable vinyl group. By taking advantage of the polymerizable characteristics of the vinyl group, KS1 was polymerized with 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AM) to form K(+) sensing films for extracellular sensing. The sensitivity of the films to potassium ions can be further tuned through the adjustment of the HEMA and AM weight ratios as well as introduction of positive or negative charge-containing segments. KS1 and its poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) (PHEMA-co-PAM) thin films show high selectivity for K(+) over competing sodium ions (Na(+)) at physiological concentrations. Extracellular sensing was demonstrated using a KS1-conjugated PHEMA-co-PAM thin film to measure the K(+) efflux of Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) stimulated by lysozyme. Meanwhile, KS1 itself permeates human glioblastoma U87MG and human esophagus premalignant CP-A cell lines. KS1 was used to monitor K(+) efflux stimulated by adenosine-5'-triphosphate (ATP), amphotericin, and a mixture of nigericin, bumetanide and ouabain, demonstrating application of this material as an intracellular potassium ion sensor.
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PMID:Triazacryptand-based fluorescent sensors for extracellular and intracellular K+ sensing. 2185 34


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