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 conformation of the milk protein alpha-lactalbumin has been studied using vibrational circular dichroism (VCD) and compared to parallel studies on lysozyme. These proteins have been shown by Acharya et al. [(1989) J. Mol. Biol. 208, 99-127] to have very similar three-dimensional crystal structures. However, their VCD spectra in D2O solution are quite different. The VCD of lysozyme in D2O more resembles that of alpha-lactalbumin in 33% propanol/D2O, under which conditions alpha-lactalbumin has conformationally transformed to a structure with increased helical fraction. These results can be seen to be consistent with UVCD and resolution-enhanced FTIR spectra of alpha-lactalbumin and lysozyme in both D2O and H2O environments. The solvent sensitivity of the alpha-lactalbumin spectra and hence of its conformation contrasted with the lack of such sensitivity for lysozyme suggest that the alpha-lactalbumin crystal structure represents a conformation different from that which is dominant in aqueous solution.
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PMID:Comparison of alpha-lactalbumin and lysozyme using vibrational circular dichroism. Evidence for a difference in crystal and solution structures. 193 71

A 42-kDa bovine protein that binds bovine angiogenin [angiogenin binding protein (AngBP)] has been identified as a dissociable cell-surface component of calf pulmonary artery endothelial cells and a transformed bovine endothelial cell line, GM7373. Binding of 125I-labeled bovine angiogenin (125I-Ang) to AngBP occurs with an apparent Kd approximately 5 x 10(-10) M and is specific, saturable, and inhibited by excess unlabeled angiogenin. 125I-Ang can be crosslinked efficiently to AngBP by a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbo-diimide. Bovine ribonuclease A competes with the binding of 125I-Ang to AngBP, but lysozyme does not. Direct binding to AngBP of 125I-labeled bovine ribonuclease A is, however, much weaker than that of 125I-Ang. Two enzymatically active derivatives of angiogenin cleaved at residues 60-61 and 67-68, respectively, fail to induce angiogenesis and also bind to AngBP only weakly. AngBP has been isolated by treatment of cells with heparan sulfate, affinity chromatography on angiogenin-Sepharose of the material dissociated from the cell surface, and gel filtration HPLC. The results suggest that AngBP has the characteristics of a receptor that may likely function in angiogenesis.
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PMID:An angiogenin-binding protein from endothelial cells. 200 62

We investigated protein accumulation on disposable extended wear contact lenses. Fifteen volunteers were fit with one low water content, non-ionic lens (Bausch & Lomb's SeeQuence) randomly assigned to one eye and a high water content ionic lens (Vistakon's Acuvue) assigned to the fellow eye. During the first 7 weeks of extended wear the lenses were removed weekly for sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of protein deposition, and replacement lenses were inserted. Four subjects completed additional test sessions of 1 minute, 15 minutes, 24 hours, and 1 week extended wear. Lysozyme accumulation, as measured by SDS-PAGE, increased with wearing times up to one week on all Acuvue lenses, but after 24 hours wear lysozyme accumulation did not increase on the SeeQuence lens. Proteins falling into the reported molecular weight ranges of albumin, PMFA, IgG, IgA (sec), lactoferrin and subunits of protein G were evident on all gels at 1 minute of wear, but these protein groups did not have a detectable increase in deposition after 24 hours wear for either the SeeQuence or the Acuvue lenses. In most cases, the protein accumulation evident from SDS-PAGE analysis was not observable by biomicroscopy using standard clinical methods. A few patients reported preference for the initial comfort and vision achieved by the Acuvue lens, but no preference was found after adaptation.
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PMID:Protein accumulation on disposable extended wear lenses. 200 85

Free energy simulation methods are used to analyze the effects of the mutation Arg 96----His on the stability of T4 lysozyme. The calculated stability change and the lack of significant structural rearrangement in the folded state due to the mutation are in agreement with experimental studies [Kitamura, S., & Sturtevant, J. M. (1989) Biochemistry 28, 3788-3792; Weaver, L. H., et al. (1989) Biochemistry 28, 3793-3797]. 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. Of particular interest is the importance of the contributions of more distant residues, solvent water, and the covalent linkage of the mutated amino acid. Also, the analysis of the interactions of Arg/His 96 with the C-terminal end of a helix (residues 82-90) makes it clear 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.
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PMID:Simulation analysis of the stability mutant R96H of T4 lysozyme. 200 62

Pure DMSO (instead of water) is used as the reaction medium for protein separations. It is shown that common extracellular proteins (i) have high solubility in DMSO (1-50 mg/ml), (ii) do not irreversibly inactivate in this solvent, and (iii) can adsorb onto carboxymethyl cellulose in DMSO and be subsequently fully desorbed in this solvent by inorganic salts. Ion-exchange chromatography on this resin in DMSO has been used to purify bovine pancreatic trypsin and to separate it from hen egg-white lysozyme in their mixture. Another approach to protein separation in DMSO, fractional precipitation with ethyl acetate (which does not dissolve proteins), has been verified with a mixture of bovine pancreatic chymotrypsinogen and chicken egg ovalbumin.
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PMID:Protein separation and purification in neat dimethyl sulfoxide. 203 25

The temperature dependence of the apparent expansibility of lysozyme and ovalbumin in solution has been measured as a function of pH. This temperature dependence is explained in terms of suppressed fluctuations in bound water due to the protein. It is shown that the thermal expansion coefficient of bound water is different from bulk water. The pH dependence can be explained by increased hydration of side chains at lower pH. The amount in volume of hydration water in a typical protein-water system varies from 0.16 to 0.7. How the intrinsic thermal expansion coefficient of proteins can be derived from the apparent quantity is discussed. Intrinsic values of the thermal expansion coefficient for lysozyme at room temperature are between 1.7 and 4.4 x 10(-4) K-1 for a 10% solution.
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PMID:Anomalous temperature dependence of the thermal expansion of proteins. 204 46

The effect of adsorbed substances on the properties of the water in various hydrogel contact lens materials was examined by exposing contact lenses (Hydron Zero 4, B&L 70, DuraSoft 3, Vistamarc, and Acuvue) to an artificial tear solution for various periods up to 14 days. The only materials affected were the high-water/ionic lenses which adsorbed a large amount of protein, predominantly lysozyme. In the DuraSoft 3 lenses the equilibrium water content (EWC) dropped from 49% to 46% and the freezing water from 28% to 21%. Similar changes were seen with the Vistamarc lenses. After a 10-day exposure of the Acuvue lens to artificial tears, the EWC decreased from 53% to 47% and the amount of freezing water from 33% to 23%. The decrease in the permeability of water seen with these materials was consistent with the decrease of the freezing water, i.e., the water able to participate in diffusion. Since the content of freezing water determines the transport through hydrogels it can be expected that any lens characteristics that depend upon the amount of this portion of water would be affected by the presence of proteins inside the polymer matrix. We extrapolated that an absolute change of 10% in the amount of freezing water could lead to a decrease in oxygen permeability of as much as 7 Dk units. In view of this work more attention should be given to changes in the properties of lenses during wear, in particular, in the high-water/ionic lenses.
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PMID:Effect of proteins on water and transport properties of various hydrogel contact lens materials. 204 86

We used the heat denaturation of lysozyme to induce the in vitro formation of protein deposits on 60 poly-HEMA contact lenses (38.6% water). Each lens was individually placed in 20 mL of a 0.04% lysozyme solution. The lenses were divided into two equal groups. In the first group (30 lenses), bendazac lysine (100 mg) was added to the lysozyme solution. The second group of lenses was used as control. Quantitative analysis of protein deposits on the lenses of both groups was carried out by a colorimetric test. In the lenses where deposit formation occurred in the presence of bendazac lysine, a mean protein level of 7.17 +/- 3.42 micrograms per lens was found; in the control group the mean value was 30.6 +/- 8.22 micrograms per lens. Student's t-test showed this difference to be significant (P less than 0.001).
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PMID:Use of bendazac lysine to limit protein deposition on soft contact lenses in vitro. 204 21

A high resolution structure of hen egg-white lysozyme containing 36 +/- 1 mol H2O per mol of protein has been obtained using triclinic (P1) crystals cross-linked with glutaraldehyde. Analysis of dehydration-induced structural changes has revealed displacement in relative position of domains and numerous small displacements in positions of individual atoms with r.m.s. deviation of main atoms 0.60 A, and that of all atoms 0.97 A. An increase in the average packing density of atoms in dry lysozyme by 4-6% seems to be the most probable reason for the loss of its activity and mobility.
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PMID:Comparison of structures of dry and wet hen egg-white lysozyme molecule at 1.8 A resolution. 206 Jun 33

Infrared spectra have been obtained for 12 globular proteins in aqueous solution at 20 degrees C. The proteins studied, which vary widely in the relative amounts of different secondary structures present, include myoglobin, hemoglobin, immunoglobulin G, concanavalin A, lysozyme, cytochrome c, alpha-chymotrypsin, trypsin, ribonuclease A, alcohol dehydrogenase, beta 2-microglobulin, and human class I major histocompatibility complex antigen A2. Criteria for evaluating how successfully the spectra due to liquid and gaseous water are subtracted from the observed spectrum in the amide I region were developed. Comparisons of second-derivative amide I spectra with available crystal structure data provide both qualitative and quantitative support for assignments of infrared bands to secondary structures. Band frequency assignments assigned to alpha-helix, beta-sheet, unordered, and turn structures are highly consistent among all proteins and agree closely with predictions from theory. alpha-Helix and unordered structures can each be assigned to only one band whereas multiple bands are associated with beta-sheets and turns. These findings demonstrate a method of analysis of second-derivative amide I spectra whereby the frequencies of bands due to different secondary structures can be obtained. Furthermore, the band intensities obtained provide a useful method for estimating the relative amounts of different structures.
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PMID:Protein secondary structures in water from second-derivative amide I infrared spectra. 215 34


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