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)

A nonionic, high-water-content, high-strength hydrogel based on N-vinyl pyrrolidinone (NVP) and a novel hydrophilic-bulky monomer, 4-t-butyl-2-hydroxycyclohexylmethacrylate (TBCM), was developed. The TBCM was prepared in three relatively simple, high-yield steps. The copolymerization of NVP with varying concentrations of TBCM resulted in transparent hydrogel films possessing a wide range in mechanical and physical properties. A copolymer composition of 91.7 parts NVP, 8.0 parts TBCM, and 0.3 parts ethylene glycol dimethacrylate (EGDMA) gave a transparent, flexible film possessing a water content of 86%, a modulus of 130 g/mm2, and a tear strength of 3.4 g/mm. In contrast, a copolymer composition of 49.7 parts NVP, 50 parts TBCM, and 0.3 parts EGDMA gave a transparent, hard hydrogel film possessing a water content of 26% and a modulus of 86,000 g/mm2. All of the high-water copolymer compositions developed resulted in lysozyme uptake typical of nonionic high-water-content hydrogels and oxygen permeability levels greater than 50 (cm3-O2(STP).cm)/(s.cm2.mm Hg) x 10(-11).
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PMID:High-strength hydrogels based on N-vinyl pyrrolidinone and 4-t-butyl-2-hydroxycyclohexylmethacrylate. 157 35

Macrophages and granulocytes seem to play a key role in the pathogenesis of bacterial meningitis. Transforming growth factor beta (TGF-beta) leads to macrophage deactivation, as well as to inhibition of cytokine production and of endothelial granulocyte adhesion. We have investigated the influence of TGF-beta on regional cerebral blood flow (rCBF), intracranial pressure (ICP), and brain edema formation during the early phase of experimental meningitis. Rats which were inoculated intracisternally with live pneumococci or with pneumococcal cell wall hydrolyzed by the M1 muramidase (PCW-M) developed an increase of rCBF and ICP within 4 h postintracisternal challenge. A single intraperitoneal injection of TGF-beta 2 but not of TGF-beta 2 vehicle-control prevented the changes of rCBF. Furthermore, TGF-beta 2 significantly reduced the increase of ICP in rats inoculated with PCW-M. Likewise, the elevation of brain water content after intracisternal injection of pneumococci or PCW-M was blocked by pretreatment of rats with TGF-beta 2. TGF-beta 1 exhibited similar inhibitory effects in PCW-M-injected rats. The beneficial effects of TGF-beta 2 on the initial phase after pneumococcal inoculation seem to be tumor necrosis factor alpha- (TNF-alpha) independent since (a) intracisternal or intraperitoneal injection of neutralizing anti-TNF-alpha antibodies did not significantly influence rCBF, ICP, and brain water content in PCW-M-induced meningitis; and (b) TNF-alpha was only occasionally detected at low levels in cerebrospinal fluid at 4 h after PCW-M application.
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PMID:Transforming growth factor beta 2 inhibits cerebrovascular changes and brain edema formation in the tumor necrosis factor alpha-independent early phase of experimental pneumococcal meningitis. 161 60

Protonic conduction studies are reported for lysozyme as a function of the number of bound water molecules. Lysozyme samples employing proton-injecting palladium black electrodes exhibited conductivities up to eight orders of magnitude greater than those retained between control (copper) electrodes. The results indicate that water involved in multiple hydrogen bond contact with the enzyme together with hydrogen bonded segments of the enzyme structure provide a hydrogen bond network which is capable of supporting considerable protonic conduction.
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PMID:Proton pathways in lysozyme. 165 Feb 49

Proton spin-lattice relaxation measurements were performed in 10 mM lysozyme solution as a function of temperature and degree of substitution of solvent H2O with D2O. The results show that in the temperature range from 274 to 323 K, the intermolecular lysozyme proton water proton coupling contributes appreciably to the observed water proton relaxation rate. In this system exchange between water protons and labile protein protons does not dominate the behaviour with temperature of the water-lysozyme intermolecular contribution to the spin-lattice relaxation.
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PMID:Nature of lysozyme-water interactions by proton NMR. 165 41

Analysis of thermodynamic data on the dissolution of solid cyclic dipeptides into water in terms of group additivity provides a rationale for the enthalpy and entropy convergence temperatures observed for small globular protein denaturation and the dissolution of model compounds into water. Convergence temperatures are temperatures at which the extrapolated enthalpy or entropy changes for a series of related compounds take on a common value. At these temperatures (TH* and TS*) the apolar contributions to the corresponding thermodynamic values (delta H degrees and delta S degrees) are shown to be zero. Other contributions such as hydrogen bonding and configurational effects can then be evaluated and their quantitative effects on the stability of globular proteins assessed. It is shown that the denaturational heat capacity is composed of a large positive contribution from the exposure of apolar groups and a significant negative contribution from the exposure of polar groups in agreement with previous results. The large apolar contribution suggests that a liquid hydrocarbon model of the hydrophobic effect does not accurately represent the apolar contribution to delta H degrees of denaturation. Rather, significant enthalpic stabilizing contributions are found to arise from peptide groups (hydrogen bonding). Combining the average structural features of globular proteins (i.e. number of residues, fraction of buried apolar groups and fraction of hydrogen bonds) with their specific group contributions permits a first-order prediction of the thermodynamic properties of proteins. The predicted values compare well with literature values for cytochrome c, myoglobin, ribonuclease A and lysozyme. The major thermodynamic features are described by the number of peptide and apolar groups in a given protein.
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PMID:Solid model compounds and the thermodynamics of protein unfolding. 166 Sep 31

Heisenberg spin exchange rates and dipole-dipole spin lattice relaxation rates for deuterated 14N- and 15N-spin labels bound selectively to the histidine His15 and to the lysines Lys13, 96, 97 of the lysozyme molecule have been determined with the aid of electron spin resonance spectroscopy. The results can be interpreted in terms of a two dimensional translational diffusion of the nitroxide tips of the spin labels along the protein surface within restricted surface areas. The spin labels are regarded as models for long amino acid side chains and as probes for the dynamics of protein and water in the vicinity of the protein surface. The translational diffusion coefficient DII is reduced by a factor of between six and thirty compared to the value for T = 295 K is given by (1.3 +/- 0.6) x 10 -10m2s-1 greater than or equal to DII greater than or equal to (2.4 +/- 0.3) x 10-11M2s-1.
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PMID:Two dimensional diffusion of small molecules on protein surfaces: an EPR study of the restricted translational diffusion of protein-bound spin labels. 166 24

Spin-lattice relaxation rates of water protons in hydrated immobilized lysozyme are measured as a function of magnetic field strength. The dependence of water relaxation versus hydration is presented from 35 to 55% by weight water content. The water-proton relaxation is directly coupled to that of the protein and the coupling exists in the absence of chemical exchange. A model is applied where relaxation within the two proton phases is coupled through a dipolar cross-relaxation mechanism as well as chemical exchange. The observed amplitudes of the water-proton relaxation profiles scale with the ratio of protein to water protons as well as the protein-proton relaxation rate. The field dependence of the protein-proton spin-lattice relaxation is presented in the presence of D2O where a cross-relaxation coupling is absent. The coupled relaxation model accounts well for the NMR relaxation data as a function of magnetic field strength which is similar to measurements on other heterogeneous systems such as tissues.
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PMID:Water-proton nuclear magnetic relaxation in heterogeneous systems: hydrated lysozyme results. 166 92

Goodford's GRIN/GRID method is used for the prediction of antigenic determinants of lysozyme by calculation of protein-water interaction energies. The comparison of the regions of high interaction energy with experimentally determined contact surfaces in antigen-antibody complexes and epitopes obtained by cross-reactivity measurements shows a noteworthy agreement. The model is proposed to enlarge the basis of theoretical models for epitope prediction. It may contribute to the increase of the prediction value when applied together with other methods.
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PMID:Protein-water interaction energies as predictor for antigenic determinants. 170 Feb 85

The three-dimensional crystal structure of the complex between the Fab from the monoclonal anti-lysozyme antibody D1.3 and the antigen, hen egg white lysozyme, has been refined by crystallographic techniques using x-ray intensity data to 2.5-A resolution. The antibody contacts the antigen with residues from all its complementarity determining regions. Antigen residues 18-27 and 117-125 form a discontinuous antigenic determinant making hydrogen bonds and van der Waals interactions with the antibody. Water molecules at or near the antigen-antibody interface mediate some contacts between antigen and antibody. The fine specificity of antibody D1.3, which does not bind (K alpha less than 10(5) M-1) avian lysozymes where Gln121 in the amino acid sequence is occupied by His, can be explained on the basis of the refined model.
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PMID:Crystallographic refinement of the three-dimensional structure of the FabD1.3-lysozyme complex at 2.5-A resolution. 171 73

We have developed a novel plasmid isolation procedure and have adapted it for use on an automated nucleic acid extraction instrument. The protocol is based on the finding that phenol extraction of a 1 M guanidinium thiocyanate solution at pH 4.5 efficiently removes genomic DNA from the aqueous phase, while supercoiled plasmid DNA is retained in the aqueous phase. S1 nuclease digestion of the removed genomic DNA shows that it has been denatured, which presumably confers solubility in the organic phase. The complete automated protocol for plasmid isolation involves pretreatment of bacterial cells successively with lysozyme, RNase A, and proteinase K. Following these digestions, the solution is extracted twice with a phenol/chloroform/water mixture and once with chloroform. Purified plasmid is then collected by isopropanol precipitation. The purified plasmid is essentially free of genomic DNA, RNA, and protein and is a suitable substrate for DNA sequencing and other applications requiring highly pure supercoiled plasmid.
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PMID:Plasmid purification by phenol extraction from guanidinium thiocyanate solution: development of an automated protocol. 171 49


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