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)

By using gel electrophoresis, as well as Western blotting with specific antibodies or with the lectin concanavalin A, we characterized the types and amounts of proteins that are deposited on 58% ionic and 38% nonionic water-content disposable soft contact lenses (DSCLs) worn for 1 to 21 days by asymptomatic subjects with mild to moderate myopic refractive errors. The total amounts of protein eluted from the lenses ranged from 0.1 to 80 micrograms/lens. The amount of protein deposited on 58% water-content lenses was greater than that on 38% water-content DSCLs. We did not find a strict correlation between the amount of protein deposited and the duration of wear for either type of lens. The major polypeptide fractions detected had apparent molecular weights of 14, 17, 21, 30, and 60 kD. The fractions at 14 kD-bound antibodies specific for human lysozyme, and those at 17 kD corresponded to prealbumin. The 60 kD fraction included IgG heavy chains. The identity of the fractions at 21 kD and 30 kD is unknown. Because oligosaccharide side chains on the proteins attract microbes and facilitate their adherence, knowledge about the types of carbohydrate moieties in lens deposits can provide a rational approach to inhibiting or reversing microbial infection.
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PMID:Analysis of glycoprotein deposits on disposable soft contact lenses. 173 May 32

Tear lysozyme levels in various types of asymptomatic contact lens wearers were compared with those in age- and sex-matched healthy control subjects. We used a radial immunodiffusion technique, and the lysozyme levels were in the normal range in controls and contact lens wearers. A comparison of the tear lysozyme levels of 27 contact lens wearers (mean, 1.05 +/- 0.45 g/L) with 22 control subjects (mean, 0.84 +/- 0.39 g/L) was statistically significant (P less than .05). The mean tear lysozyme levels of rigid (1.12 +/- 0.54 g/L, P less than .05) and high water-content (1.20 +/- 0.43 g/L, P less than .03) contact lens wearers were increased in comparison with the control group. The tear lysozyme difference was significant (P less than .03) between high and low water-content (0.82 +/- 0.20 g/L) contact lens users. Our study revealed that, although most of the contact lens wearers were asymptomatic and there was no pathologic sign of external ocular inflammation, a change in tear lysozymes was observed. Contact lens wear is irritating to the cornea and conjunctiva, and tear lysozyme physiology is disturbed most by high water-content contact lenses.
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PMID:Tear lysozyme levels in contact lens wearers. 175 Jul 38

Adsorption isotherms of BSA at the solid-water interfaces have been studied as a function of protein concentration, ionic strength of the medium, pH and temperature using silica, barium sulphate, carbon, alumina, chromium, ion-exchange resins and sephadex as solid interfaces. In most cases, isotherms for adsorption of BSA attained the state of adsorption saturation. In the presence of barium sulphate, carbon and alumina, two types in the isotherms are observed. Adsorption of BSA is affected by change in pH, ionic strength and temperature of the medium. In the presence of metallic chromium, adsorbed BSA molecules are either denatured or negatively adsorbed at the metallic interface. Due to the presence of pores in ion-exchange resins, adsorption of BSA is followed by preferential hydration on resin surfaces in some cases. Sometimes two steps of isotherms are also observed during adsorption of BSA on the solid resins in chloride form. Adsorption of BSA, beta-lactoglobulin, gelatin, myosin and lysozyme is negative on Sephadex surface due to the excess adsorption of water by Sephadex. The negative adsorption is significantly affected in the presence of CaCl2, KSCN, LiCl, Na2SO4, NaI, KCl and urea. The values of absolute amounts of water and protein, simultaneously adsorbed on the surface of different solids, have been evaluated in some cases on critical thermodynamic analysis. The standard free energies (delta G0) of excess positive and negative adsorption of the protein per square meter at the state of monolayer saturation have been calculated using proposed universal scale of thermodynamics. The free energy of adsorption with reference to this state is shown to be strictly comparable to each other. The magnitude of standard free energy of transfer (delta G0B) of one mole of protein or a protein mixture at any type of physiochemical condition and at any type of surface is observed to be 38.5 kJ/mole.
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PMID:Protein adsorption at solid-liquid interfaces: Part IV--Effects of different solid-liquid systems and various neutral salts. 175 29

Of the interactions that govern protein adsorption on polymer surfaces, solvation interactions (repulsive hydration and attractive hydrophobic interactions) are thought to be among the most important. The solvation interactions in protein adsorption, however, have not been dealt with in theoretical calculation of the adsorption energy owing to the difficulties in modelling such interactions. We have evaluated the solvation interaction energies using the fragment constant method of calculating the partition coefficients of amino acids. The fundamental assumption of this approach is that the partition coefficients of amino acids between water and organic solvent phases are related to the free energies of transfer from bulk water to the polymer surface. The X-ray crystallographic protein structures of lysozyme, trypsin, immunoglobulin Fab, and hemoglobin from the Brookhaven Protein Data Bank were used. The model polymer surfaces were polystyrene, polypropylene, polyethylene, poly(hydroxyethyl methacrylate) [poly(HEMA)], and poly(vinyl alcohol). All possible adsorption orientations of the proteins were simulated to study the effect of protein orientation on the solvation interactions. Protein adsorption on either hydrophobic or hydrophilic polymer surfaces was examined by considering the sum of solvation and other interaction energies. The results showed that the contribution of the solvation interaction to the total protein adsorption energy was significant. The average solvation interaction energy ranged from -259.1 to -74.1 kJ/mol for the four proteins on the hydrophobic polymer surfaces, such as polystyrene, polypropylene, and polyethylene. On the other hand, the average solvation interaction energies on hydrophilic surfaces such as poly(HEMA) and poly(vinyl alcohol) were larger than zero. This indicates that repulsive hydration interactions are in effect for protein adsorption on hydrophilic polymer surfaces. The total interaction energies of the proteins with hydrophobic surfaces were always lower than those with more hydrophilic surfaces. This trend is in agreement with the experimental observations in the literature. This study suggests that consideration of the solvation interaction energies is necessary for accurate calculation of the protein adsorption energies.
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PMID:Calculation of solvation interaction energies for protein adsorption on polymer surfaces. 176 35

Pseudomonas aeruginosa PAO1 released a significant amount of a cytoplasmic enzyme, glucose-6-phosphate dehydrogenase, in the presence of aminoglycoside and lysozyme. The extent of the enzyme release was inversely related to the MICs of the aminoglycoside. However, the aminoglycoside-resistant strain F3721, treated in the same way; released a less enzyme. The F3721 LPS was extracted in the phenol phase instead of the water phase in which PAO1 LPS was easily extracted. Electrophoretic analysis of the F3721 LPS showed the ladder bands at the high Mr position, suggesting that the LPS of the aminoglycoside-resistant cells has a structural modification(s) which somehow protects the outer membrane from aminoglycoside-mediated damage.
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PMID:Aminoglycoside resistance in Pseudomonas aeruginosa due to outer membrane stabilization. 179 Jul 21

Free energy simulation methods are used to analyse the effects of the mutation Arg-96----His on the stability of bacteriophage T4 lysozyme and of Ile-96----Ala on the stability of barnase. By use of thermodynamic integration, the contributions of specific interactions to the free energy change are evaluated. It is shown that a number of contributions that stabilize the wild-type or the mutant partially cancel in the overall free energy difference; some of these involve the unfolded state. Comparison of the results with conclusions based on structural and thermodynamic data leads to new insights into the origin of the stability difference between wild-type and mutant proteins. For the charged-to-charged amino acid mutation in T4 lysozyme, the importance of the contributions of more distant residues, solvent water and the covalent linkage involving the mutated amino acid are of particular interest. Also, the analysis of the Arg-96 to His mutation with respect to the interactions with the C-terminal end of a helix (residues 82-90) indicates that the nearby carbonyl groups (Tyr-88 and Asp-89) make the dominant contribution, that the amide groups do not contribute significantly and that the helix dipole model is inappropriate for this case. For the non-polar-to-non-polar amino acid mutation in barnase, the solvent contribution is unimportant, and covalent terms are shown to be significant because they do not cancel between the folded and unfolded state.
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PMID:Simulation analysis of the stability mutants R96H of bacteriophage T4 lysozyme and I96A of barnase. 181 97

Fast atom bombardment mass spectrometry (FAB) was used to determine the glycation sites of lysozyme in a restricted water environment. A 30-day incubation at 25 degrees C, and 65% relative humidity (R.H.) resulted in glycation at lysine-1 while a much shorter (3-day) incubation at 50 degrees C and 65% R.H. resulted in diglycation at lysine-1 as well as glycation at lysine-13 and lysine-33.
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PMID:Glycation of lysozyme in a restricted water environment. 181 46

Using an aqueous solvent of high methanol content, we have been able to extend the use of Coomassie blue R protein staining to contact lens-type acrylate hydrogels of 35-80% water content. Protein deposition on a wide range of hydrogels was compared after exposure to protein and there was good agreement between in vitro and in vivo studies to assess deposit resistance. Staining was sensitive down to a 2 micrograms lysozyme/cm2 zone extending from one polymer surface to the other, and linear with protein content up to 40 micrograms/cm2. The staining method permits unusual deposit morphologies to be easily visualized and is best used for qualitative or semiquantitative evaluation of protein deposition during the development of new polymeric materials. We propose a new classification system for protein deposition based on the degree of Coomassie blue R staining.
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PMID:Detection of protein deposition on contact lens type polymeric hydrogels by Coomassie blue R staining. 185 94

Bacterial threads of Bacillus subtilis have been immersed in, and redrawn from, water of various pH values, in solutions of (NH4)2SO4 and NaCl of various concentrations, and in lysozyme solutions. The changes in the tensile strength, elastic modulus, and other mechanical properties of the bacterial cell wall due to these treatments were obtained. The data show that change in pH has little effect but that as the salt concentration is increased, the cell walls become more ductile. A high salt concentration (1 M NaCl) can reduce the modulus by a factor of 26 to 13.5 MPa at 81% relative humidity and the strength by a factor of only 2.5. Despite attacking the septal-wall region of the cellular filaments, lysozyme has no effect on the mechanical properties. There is no significant change in the stress relaxation behavior due to any of the treatments. The dependence of mechanical properties on the salt concentration is discussed in terms of the polyelectrolyte nature of cell walls. The evidence presented in this and the accompanying paper (J. J. Thwaites and U.C. Surana, J. Bacteriol., 173:197-203, 1991) supports the idea that the peptidoglycan in bacterial cell wall is an entanglement network with a large degree of molecular flexibility, with some order but no regular structure.
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PMID:Mechanical properties of Bacillus subtilis cell walls: effects of ions and lysozyme. 189 21

The unfolding and refolding kinetics of six proline mutants of the human lysozyme (h-lysozyme) were carried out and compared to that of the wild-type protein. Our results show that the slow refolding phase observed in the h-lysozyme refolding kinetics cannot be ascribed to proline isomerization reactions. The h-lysozyme contains two proline residues at positions 71 and 103, both in the trans conformation in the native state. The refolding kinetics of the P71G/P103G mutant, in which both prolines have been replaced by a glycine, were found to be similar to those of the wild-type protein. The same slow phase amplitude of about 10% was found for both proteins, and the slow phase rate constants were also identical within experimental error. Other mutants such as P103G or P71G, in which only one of the two prolines has been replaced by a glycine, and A47P with its three prolines, gave identical slow refolding phases. The X-ray structure analysis and scanning microcalorimetric study of each protein (Herning et al., unpublished experiments) have confirmed that none of the considered mutations affects significantly protein structure and that no major changes in protein stability were brought about by these mutations. Therefore, comparison of the properties of the mutant and wild-type proteins is legitimate. Interestingly, the refolding kinetics of the V110P mutant, in which a proline residue has been introduced at position 110 (N-terminus of an alpha-helix), were clearly triphasic. For this mutant an additional very slow phase with properties similar to those expected from the proline hypothesis was detected. Equilibrium denaturation studies were conducted for each protein, and the refolding pathway of h-lysozyme is partly presented. We also discuss the effect of proline mutations on the energetics of the folding pathway of the h-lysozyme in water.
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PMID:Effects of proline mutations on the unfolding and refolding of human lysozyme: the slow refolding kinetic phase does not result from proline cis-trans isomerization. 191 79


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