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)

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

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

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

The heterobifunctional reagent, N-succinimidyl 3-(2-pyridyldithio)propionate, was utilized for controlled coupling of lysozyme and bovine serum albumin to Sepharose-gelatin. Initially the protein (lysozyme or bovine serum albumin) was reacted with N-succinimidyl 3-(2-pyridyldithio)propionate at the free amino groups to give 3-(2-pyridyldithio)propionyl-protein. The latter was reduced to thiopropionyl-protein and was conjugated to 3-(2-pyridyldithio)-propionyl-Sepharose-gelatin through sulfhydryl-disulfide exchange. Sepharose-gelatin-lysozyme and Sepharose-gelatin-albumin were prepared in this manner. They were capable of binding their respective antibody and the eluted antibody was found to be pure on electrophoresis in SDS-polyacrylamide gels and to show heterogeneity by isoelectric focusing. Antibodies bound to Sepharose-gelatin-albumin were found to be less tightly bound to the immunoadsorbent than in the case of Sepharose-albumin, as more antibodies were eluted on the former immunoadsorbent with 0.1 M glycine-HCl (pH 3) than on the latter. The new method permits controlled coupling of proteins to an insoluble matrix (Sepharose-gelatin), and the bond through which reaction occurs is known with precision.
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PMID:A novel preparation of immunoadsorbents. Controlled coupling of proteins to Sepharose-gelatin by heterobifunctional reagent. 719 90

Two proteinaceous lysozyme inhibitors, hen-egg-white lysozyme inhibitors F-I and F-II, were isolated from the culture broth of a bacterial strain identified as Pseudomonas aeruginosa M-1001. Maximum lysozyme inhibitory activity was obtained when the bacterium was grown aerobically in a medium consisting of 0.25% glucose, 0.25% beef extract, 0.25% polypepton, 1.0% sodium L-glutamate, and 1.0% soluble starch (pH 7.0) at 37 degrees C after 20-24 hrs. F-I and F-II were purified 20 and 7.5-fold, respectively, from the culture supernatant of P. aeruginosa M-1001 by ammonium sulfate fractionation, DEAE-Sepharose CL-6B column chromatography, and Sephacryl S-200 gel chromatography. The molecular weights of F-I and F-II were estimated to be about 57,000 and 33,000, by SDS-PAGE, respectively. F-I was stable in a pH range between 6 and 10 and below 50 degrees C. F-II was stable in a pH range between 6 and 11 and below 40 degrees C. Many Gram-positive bacteria were found to be inhibited by the crude lysozyme inhibitors.
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PMID:Production, purification and characterization of two proteinaceous hen-egg-white lysozyme inhibitors from Pseudomonas aeruginosa M-1001. 748 Mar 63

We studied the role of N-glycosylation of human lactoferrin (hLF) with respect to properties that are relevant to its antibacterial and anti-inflammatory activities. A human kidney-derived 293(S) cell line that constitutively expresses recombinant hLF (rhLF) was produced. The reactivity towards various antibodies of rhLF that had been expressed in the absence or presence of tunicamycin (which blocks N-linked glycosylation) did not differ from that of natural (human milk-derived) hLF. Cation-exchange chromatography and N-terminal protein sequencing showed identical cationic properties and an intact N-terminal sequence for rhLF and natural hLF. SDS/PAGE of rhLF expressed in the presence of tunicamycin revealed a protein with the same M(r) as that of enzymically deglycosylated natural hLF. Both glycosylated and unglycosylated rhLF appeared to be completely saturated with iron. The affinity of natural hLF, glycosylated and non-glycosylated rhLF for both human lysozyme (Kd 4.5 x 10(-8) M) and bacterial lipopolysaccharide did not differ. SDS/PAGE of hLF species subjected to trypsin indicated that unglycosylated rhLF was much more susceptible to degradation. Furthermore, this analysis suggests that N-glycosylation heterogeneity in natural hLF and rhLF resides in the C-lobe. Thus our results provide no argument for differential antibacterial and/or anti-inflammatory activity of natural and (glycosylated) rhLF and suggest that a major function of glycosylation in hLF is to protect it against proteolysis.
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PMID:Glycosylated and unglycosylated human lactoferrins both bind iron and show identical affinities towards human lysozyme and bacterial lipopolysaccharide, but differ in their susceptibilities towards tryptic proteolysis. 749 99


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