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)

Using strains of Streptococcus mutans suspended in human saliva, the salivary proteins capable of binding to the surface of the bacteria were identified by immunological and electrophoretic techniques. Six binding components were recognized: IgA, lysozyme, some high molecular weight material (greater than 400,000), probably a glycoprotein, a low molecular weight component (11-13,000), a 150,000 mol. wt protein, and one major component, mol. wt 20-25,000 which did not resolve fully on SDS-polyacrylamide electrophoresis. All these salivary components could be desorbed from the bacteria with 1 M NaCl, and subsequent extraction of the same cells with 6 M guanidine-HCl did not release any more salivary material. The significance of the binding of these salivary components is unknown but some may modify the behaviour of the organisms in vivo.
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PMID:The adsorption of human salivary components to strains of the bacterium Streptococcus mutans. 659 86

The outer membrane of Vibrio parahaemolyticus strain 3283-61 (serotype O2:K3) was isolated from blebs released upon spheroplast formation, in the presence of lysozyme and EDTA, by isopycnic sucrose density gradient centrifugation. SDS-PAGE of the outer membrane fraction prepared from cells grown in nutrient broth containing 3% (w/v) NaCl revealed five major proteins, designated a to e, with apparent approximate molecular weights: a, 44 000; b, 36 000; c, 33 500; d, 26 500; e, 22 000. An increase in NaCl concentration in the growth medium resulted in an increase of proteins b and c, whereas a decrease to 0.5% (w/v) induced two additional major proteins with respective molecular weights of about 35 000 and 32 000. Proteins a and b appeared to be loosely associated with the peptidoglycan layer since they were largely retained after extraction with 2% (w/v) SDS at 50 degrees C for 30 min. Proteins c and/or e may play a role in phage VP1-receptors since phage-resistant mutants derived from strain 3283-61 had significantly diminished amounts of both proteins. The major outer membrane proteins varied in number and molecular weight in strains of V. parahaemolyticus belonging to different K-serotypes.
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PMID:Isolation and characterization of the outer membrane from Vibrio parahaemolyticus. 665 59

Circular dichroism measurements revealed that hen egg-white lysozyme underwent multiple conformational transitions upon the addition of acetic acid. The transitions were reversible as judged from complete recoveries of enzymatic activity, electrophoretic mobility in SDS-polyacrylamide gel, and of ellipticity. Two transitions, with the mid-concentrations of 26 and 38% (v/v), were observed with the CD spectra in the amide absorption region. The two transitions were essentially athermal in the temperature ranges, 0 to 25 degrees C for the former and -10 to 10 degrees C for the latter. The trough ellipticity for the product of the transition at the higher acetic acid concentration (DII form) very closely approached the value for the synthetic polypeptides in the beta-conformation as the temperature was lowered. Molecular weight measurements by sedimentation equilibrium indicated that the products were both monomeric. Measurements of CD spectra in the aromatic absorption region showed another transition, whose mid-concentration varied with temperature from 26% (v/v) (at about 25 degrees C) to 38% (v/v) (at -10 degrees C). A change in the hydrodynamic volume detectable by exclusion chromatography was associated with this transition only.
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PMID:Multiple conformational transitions of hen egg-white lysozyme in aqueous acetic acid solutions. 669 90

We have developed methods for separating the cytoplasmic and outer membranes of vegetative cells of Myxococcus xanthus. The total membrane fraction from ethylenediaminetetraacetic acid-lysozyme-treated cells was resolved into three major fractions by isopycnic density centrifugation. Between 85 and 90% of the succinate dehydrogenase and cyanide-sensitive reduced nicotinamide adenine dinucleotide oxidase activity was found in the first (I) fraction (rho = 1.221 g/ml) and 80% of the membrane-associated 2-keto-3-deoxyoctonate was found in the third (III) fraction (rho = 1.166 g/ml). The middle (II) fraction (rho = 1.185 g/ml) appeared to be a hybrid membrane fraction and contained roughly 10 to 20% of the activity of the enzyme markers and 2-keto-3-deoxyoctonate. No significant amounts of deoxyribonucleic acid or ribonucleic acid were present in the three isolated fractions, although 26% of the total cellular deoxyribonucleic acid and 3% of the total ribonucleic acid were recovered with the total membrane fraction. Phosphatidylethanolamine made up the bulk (60 to 70%) of the phospholipids in the membrane fractions. However, virtually all of the phosphatidylserine and cardiolipin were found in fraction I. Fraction III appeared to contain elevated amounts of lysophospholipids and contained almost three times the amount of total phospholipid as compared with fraction I. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved approximately 40 polypeptides in the total membrane fraction. Two-thirds of these polypeptides were enriched in fraction I, and the remainder was enriched in fraction III. Fraction II contained a banding pattern similar to the total membrane fraction. Electron microscopy revealed that vegetative cells of M. xanthus possessed an envelope similar to that of other gram-negative bacteria; however, the vesicular appearance of the isolated membranes was somewhat different from those reported for Escherichia coli and Salmonella typhimurium. The atypically low bouyant density of the outer membrane of M. xanthus is discussed with regard to the high phospholipid content of the outer membrane.
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PMID:Separation and properties of the cytoplasmic and outer membranes of vegetative cells of Myxococcus xanthus. 676 94

The spore-coat fraction from Bacillus megaterium KM, when prepared by extraction of lysozyme-digested integuments with SDS (sodium dodecyl sulphate) and urea, contains three N-terminal residues and a major component of apparent mol.wt. 17500. Electron microscopy of this fraction shows it to consist of an ordered multilamellar structure similar to that which forms the coat region of intact spores. The 17500-dalton protein, which has been purified to homogeneity, has an N-terminal methionine residue, has high contents of glycine, proline, cysteine and acidic amino acids and readily polymerized even in the presence of thiol-reducing agents. It is first synthesized between late Stage IV and early Stage V, which correlates with the morphological appearance of spore coat. Before Stage VI the 17500-dalton protein is extractable from sporangia by SDS in the absence of thiol-reducing reagents. Between Stage VI and release of mature spores the protein becomes resistant to extraction by SDS unless it is supplemented by a thiol-reducing reagent. In addition to that of the spore-coat protein, the timing of synthesis of all the integument proteins was analysed by SDS/polyacrylamide-gel electrophoresis and non-equilibrium pH-gradient electrophoresis. Several integument proteins are conservatively synthesized from as early as 1h after the end of exponential growth (t1), which may reflect protein incorporation into the spore outer membrane.
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PMID:Characterization, purification and synthesis of spore-coat protein in Bacillus megaterium KM. 680 68

Attempts at isolating individual human milk proteins showed that cross interactions made it difficult to obtain of homogeneous components. A new method was devised, based on complete precipitation of milk proteins with saturated ammonium sulphate and progressive solubilization of the precipitate on a column of Sephadex G10 with a linear gradient of ammonium sulphate (from saturation to water). Three fractions were obtained. The first contained lactoferrin, serum albumin, lysozyme and traces of alpha-lactalbumin. Lysozyme could be obtained free from contaminants by chromatography on Ultrogel AcA 54. Lactoferrin and serum albumin coeluting as a single peak, were separated by a further chromatography on DEAE-cellulose. From the other two fractions recovered on Sephadex G10, it should be possible to prepare immunoglobulins, alpha-lactalbumin and the bulk of caseins. The homogeneity of the preparations of lysozyme, lactoferrin and serum albumin was assessed by SDS polyacrylamide gel electrophoresis, acrylamide agarose electrophoresis and immunoelectrophoresis.
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PMID:[A new method for human milk protein separation]. 682 Nov 60

Outer membrane fractions of Moraxella nonliquefaciens 7784 strains SC-c and N-b, isolated by extraction with lithium acetate, were analysed by SDS-PAGE. Three main proteins were found, of which one, with an apparent molecular weight of 19500, was undetectable in membranes isolated by lysis of lysozyme/EDTA spheroplasts. All three major proteins were heat modifiable.
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PMID:Studies on outer membrane proteins of Moraxella nonliquefaciens. 687 14

The reaction of lysozyme with OH., Br.-2 and e-aq, produced in an aqueous solution by pulsed electrons and gamma-rays, were investigated. Irradiated enzymes showed an increase in the light scattering intensity (LSI) which is proportional to the absorbed dose. Results obtained from SDS gel electrophoresis confirm dimerization of lysozyme, which is considered to be responsible for the increase in LSI. It was found that the rate constant of the dimerization of protein radicals produced in the reaction with OH. is 2K=(1.0 +/- 0.3) X 10(6)M-1 s-1 and the yield of the dimerization is 0.6 in G. The enzymatic activity of the dimer is shown to be reduced to about 30 per cent of that of the intact enzyme. It is concluded that the radiation-induced inactivation of lysozyme is largely due to dimerization.
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PMID:Dimer formation in radiation-irradiated aqueous solution of lysozyme studied by light-scattering-intensity measurement. 697 51

Sea urchin sperm contain an acrosin-like enzyme with an apparent molecular weight of 53,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals two subunits of 34,000 daltons and 18,000 daltons. The Mr = 34,000 subunit is the catalytic entity as revealed both by labeling with [14C]diisopropyl phosphorofluoridate and by proteolytic activity after dissociation of the subunits at pH 2.5. Both the 34,000-dalton and the 53,000-dalton forms of the enzyme catalyze the hydrolysis of N alpha-benzoyl-L-arginine ethyl ester and both are inactivated by inhibitors of low molecular weight, whereas only the Mr = 34,000 form is inactivated by large proteinaceous inhibitors. Only the Mr = 34,000 form catalyzes proteolysis of denatured lysozyme or the B chain of insulin. The Mr = 18,000 subunit appears to suppress the proteolytic activity but not the activity toward the small ester substrate. These findings are discussed in terms of possible roles of this enzyme in the control of early events leading to fertilization.
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PMID:Purification of an acrosin-like enzyme from sea urchin sperm. 698 19

The evolution of proteinuria in rabbits with experimentally induced chronic serum sickness was followed up longitudinally by analytical and quantitative assays. The results suggest that sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is a more sensitive index of kidney malfunction than are total-protein assays or the quantitation of albumin and lysozyme. In some rabbits that showed abnormal proteinuria by SDS-PAGE, no histologic evidence of pathologic damage or of deposition of immune complexes in the kidneys was found. This suggests that SDS-PAGE may detect functional alterations at early stages of kidney damage when the lesions are either undetectable or reversible. In one rabbit that was killed after normalization of the proteinuria, immunofluorescence tests indicated deposition of C3, IgG, and fibrinogen, but there was no histologic evidence of kidney damage.
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PMID:Experimental model of chronic serum sickness. Relationships between proteinuria, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and glomerular and extraglomerular renal pathology. 699 Aug 90


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