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 use of high water content (> 96%) hydrogels obtained from copolymerisation of bovine serum albumin and poly(ethylene glycol) as a controlled release system has been investigated. Such hydrogels allowed release of soluble and hydrophobic substances, even proteins. Release is shown to occur by a diffusion controlled mechanism, leading to half-life times of release ranging between 0.8 hour for theophylline and 4.2 hours for lysozyme, when a 2.4 mm thick disc of BSA-PEG (MW of 10000) was used. The effect of the porosity of the hydrogel on the diffusive properties of theophylline and hydrocortisone has been evaluated by varying the molecular weight of the poly(ethylene glycol). It was shown that poly(ethylene glycol) of high molecular weight leads to more porous hydrogels in which the diffusion is faster.
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PMID:Drug release from new bioartificial hydrogel. 852 54

The results of the interspecific protoplast fusion between B. thuringensis sub. kurstaki Bt-3701 which has pesticide ability, and B. megaterium var. phosphaticum Bm-107 which has decomposing phosphate activity, were reported. High frequency of protoplast formation and regeneration was obtained with 4h activated Bm-107 treated by 100 micrograms/ml lysozyme, and with 2h activated Bt-3701 treated by 3% glycin and mild temperature. Using 40% PEG and 5% nascent Ca2+ to treat the parential protoplast mixture for 3 min at 37 degrees C, 4 stable fusants were obtained. Biological tests show that they have both pesticide ability and decomposing phosphate activity, but which are weaker than that of parential strains.
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PMID:[Interspecific protoplast fusion between Bacillus thuringensis Bt-3701 and Bacillus megaterium Bm-107]. 870 82

The effect of nine organic solvents and urea on hen-eggwhite lysozyme-rabbit antilysozyme precipitin reaction was studied at a ratio of the antigen to the antibody of 1:26 by weight in 70 mM sodium phosphate buffer, pH 7.0. The organic solvents used were dioxane, acetonitrile, dimethylsulfoxide, N,N-dimethylformamide, 1-propanol, propylene glycol, trifluoroethanol, ethylene glycol and glycerol. These solvents invariably caused reduction in the amount of protein precipitated during the antigen-antibody reaction. The concentration of an organic solvent, CM, required for 50% reduction in the precipitin reaction value was determined for each organic solvent. Among the nine organic solvents, dioxane was the most potent inhibitor of the precipitin reaction. The nine organic solvents did not cause irreversible inactivation of the antigen and the antibody, and at concentrations used in this study most of them would be nondenaturing. These solvents seem to destabilize the antigen-antibody complex.
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PMID:Effect of organic solvents on lysozyme-antilysozyme precipitin reaction. 876 Jun 6

Aqueous two-phase systems composed of ethylene oxide/propylene oxide random co-polymers, EO30/PO70 or Ucon (EO50/PO50), in the top phase and dextran T500 in the bottom phase, have been studied. The cloud point diagram for EO30/PO70 in water solution was determined. EO30/PO70 has a cloud point of 32 degrees C at a concentration of 10% (w/w). The phase diagram for the system EO30/PO70-dextran T500-water was determined. Salt effects have been studied on the partitioning of two model proteins, bovine serum albumin and hen egg white lysozyme, in EO30/PO70-dextran and Ucon-dextran systems. Ions with different hydrophobicity, i.e., with different position in the Hofmeister or lyotropic series, were investigated with reference to their effect on protein partition. The counterion hydrophobicity was shown to have a strong influence on the partitioning of BSA and lysozyme. Most extreme partitioning was obtained with hydrophobic (chaotropic) ions like CIO4- and I-. A comparison of protein partitioning between PEG-dextran and EO30/PO70-dextran has been done. A more extreme protein partitioning was obtained in the EO30/PO70-dextran containing system. Temperature-induced phase separation was studied with EO30/PO70 at 45 degrees C. Both BSA and lysozyme were completely partitioned to the water phase formed above the cloud point of EO30/PO70. Model calculations, based on Flory-Huggins theory of polymer solutions, have been done which could reproduce the salt effect on the protein partitioning in aqueous-two phase system.
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PMID:Effects of ions on partitioning of serum albumin and lysozyme in aqueous two-phase systems containing ethylene oxide/propylene oxide co-polymers. 876 33

The effect of proline on the prevention of trichloroacetic acid (TCA)-induced protein precipitation is studied. It is found that proline at high concentrations (> 4.0 M) completely prevents TCA-induced precipitation of hen egg white lysozyme. Other osmolytes such as ethylene glycol, glycerol and sucrose fail to prevent the TCA-induced precipitation of lysozyme. Viscosity and 1-anilino-8-naphthalene sulphonic acid binding experiments suggest that proline at high concentration forms an ordered supramolecular assembly. Proline is shown to increase the solubility of protein due to formation of such higher order assemblies. A model of the supra-molecular assembly of proline is proposed and a possible in vivo role of the increased levels of proline under water stress is discussed.
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PMID:Proline is a protein solubilizing solute. 906 63

Myxococcus xanthus is a Gram-negative, soil-dwelling bacterium with a complex life cycle which includes fruiting body formation and sporulation in response to starvation. This developmental process is slow, requiring a minimum of 24-48 h, and requires cells to be at high cell density on a solid surface. It is known that, in the absence of starvation, vegetatively growing cell suspensions can form 'glycerol spores' when exposed to high levels of glycerol, usually 0.5 M. The cells differentiate from rods to resistant spheres rapidly (2-4 h) and synchronously. We have found that the chromosomally encoded beta-lactamase of M. xanthus can be induced by numerous beta-lactam antibiotics as well as by non-specific inducers including glycine and many D-amino acids. In addition, D-cycloserine, phosphomycin, and hen egg-white lysozyme also induce beta-lactamase in this bacterium. Unexpectedly, agents which induce beta-lactamase can induce 'glycerol spores'; all of the agents tested which induce glycerol spores (glycerol, DMSO, ethylene glycol) also induce beta-lactamase. During the induction of sporulation, beta-lactamase activity increases, reaching a peak during the morphological transition from rod-shaped cells to spherical spores. These spores are viable and resistant to many treatments which disrupt vegetatively growing rods but are not as resistant as fruiting body spores. The concomitant induction of beta-lactamase and starvation-independent sporulation suggests that these processes share a common signal-transduction pathway. These results also suggest that starvation-independent sporulation may be an adaptation of cells in order to resist agents that damage peptidoglycan structure and therefore threaten cell survival.
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PMID:Starvation-independent sporulation in Myxococcus xanthus involves the pathway for beta-lactamase induction and provides a mechanism for competitive cell survival. 919 10

Various assays of classical PEG-assisted transformation as well as electrotransformation of Streptomyces parvulus IMET41380 and Streptomyces vinaceus NCIB8852 are described. Contrary to the so far reported assays of electrotransforming Streptomyces strains, electroporation in S. parvulus and S. vinaceus was carried out on intact cells, without any lysozyme treatment. In these two strains, the classical PEG-assisted transformation of protoplasts does not work efficiently (10(3) to 10(4) transformants per micrograms of pIJ702 DNA) and electrotransformation gives 10 to 100 times higher yields (10(5) transformants per micrograms of pIJ702 DNA). The electroporation method described here is not applicable to other Streptomyces strains (S. lividans or S. coelicolor).
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PMID:Electroporation of intact cells of Streptomyces parvulus and Streptomyces vinaceus. 922 45

Fluorescence polarization spectroscopy and isothermal titration calorimetry were used to study the influence of osmolytes on the association of the anti-hen egg lysozyme (HEL) monoclonal antibody HyHEL-5 with bobwhite quail lysozyme (BWQL). BWQL is an avian species variant with an Arg-->Lys mutation in the HyHEL-5 epitope, as well as three other mutations outside the HyHEL-5 structural epitope. This mutation decreases the equilibrium association constant of HyHEL-5 for BWQL by over 1000-fold as compared to HEL. The three-dimensional structure of this complex has been obtained recently. Fluorescein-labeled BWQL, obtained by labeling at pH 7.5 and purified by hydrophobic interaction chromatograpy, bound HyHEL-5 with an equilibrium association constant close to that determined for unlabeled BWQL by isothermal titration calorimetry. Fluorescence titration, stopped-flow kinetics, and isothermal titration calorimetry experiments using various concentrations of the osmolytes glycerol, ethylene glycol, and betaine to perturb binding gave a lower limit of the uptake of approximately 6-12 water molecules upon formation of the HyHEL-5/BWQL complex.
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PMID:Involvement of water molecules in the association of monoclonal antibody HyHEL-5 with bobwhite quail lysozyme. 933 7

Proteins present in chicken egg white are separated by counter-current chromatography (CCC) in one step using a cross-axis coil planet centrifuge (X-axis CPC). The separation was performed with an aqueous polymer two-phase system composed of 16% (w/w) poly(ethylene glycol) 1000 and 12.5% (w/w) dibasic potassium phosphate by eluting the lower phase at a flow-rate of 1.0 ml/min. From about 20 g of the crude egg white solution, lysozyme, ovalbumin, and ovotransferrin were resolved within 5.5 h. Each component was identified by 12% SDS gel electrophoresis with Coomassie brilliant blue staining.
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PMID:One-step purification of proteins from chicken egg white using counter-current chromatography. 965 28

Proton nuclear magnetic resonance (1H-NMR) spectroscopy is used to identify a preferred binding site for uncharged hydrophilic polymers on the surface of hen egg-white lysozyme. Chemical shift titrations show that exchangeable proton signals from amino acids Arg-61, Trp-62, Trp-63, Arg-73, Lys-96 and Asp-101 are selectively perturbed upon binding of poly(ethylene oxide), poly(ethylene glycol) and poly(ethylene-co-propylene oxide). The greatest binding-induced chemical shift changes are observed for Trp-62, Arg-61 and Arg-73 at the edge of the active site cleft of the protein, consistent with a predominantly hydrophobic interaction mode involving the polymer ethylene moieties. The more hydrophilic species poly(dihydroxypropyl methacrylate) causes similar but substantially smaller chemical shift effects than the other polymers, confirming the nature of the interaction. A dissociation constant of 76+/-5 mM is determined for the poly(ethylene glycol)-lysozyme complex. The relatively low affinity of the protein-polymer interactions compared to oligosaccharide substrate binding suggests that lysozyme activity is minimally affected by these materials.
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PMID:A hydrophobic interaction site for lysozyme binding to polyethylene glycol and model contact lens polymers. 975 36


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