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)

Near-infrared spectroscopy (NIR) of various proteins (bovine serum albumin, lysozyme, ovalbumin, gamma-globulin, beta-lactoglobulin, myoglobin, cytochrome-c) was investigated as a possible analytical method of the protein secondary structure in various physical states. The spectra of proteins in aqueous solutions (transmission mode, solvent-compensated) and those in freeze-dried solids (nondestructive diffuse reflection mode) showed several bands at similar frequencies in the combination (4000-5000 cm(-1)) and first overtone (5600-6600 cm(-1)) spectral regions. The normalized second-derivative near-infrared spectra of proteins in aqueous solutions suggested that some bands indicated alpha-helix (4090, 4365-4370, 4615, and 5755 cm(-1)) and beta-sheet (4060, 4405, 4525-4540, 4865, and 5915-5925 cm(-1)) structures. The proteins mostly maintained spectra characteristic of their native structure after freeze-drying, although some reductions in alpha-helical structure and increase in unordered or beta-sheet structures were observed. The near-infrared analysis also showed beta-sheet formation of heat-treated BSA in aqueous solutions and in subsequently freeze-dried solids. The present results thus indicated that the nondestructive near-infrared analysis can be used for the investigation of dehydration-induced changes in protein secondary structures.
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PMID:Near-infrared analysis of protein secondary structure in aqueous solutions and freeze-dried solids. 1649 74

The separation of four proteins including RNase A, cytochrome C, lysozyme and myoglobin was investigated by reversed-phase gradient pressurized capillary electrochromatography (p-CEC) with 1.5 microm non-porous silica C18 stationary phase. This mode was compared with micro-high performance liquid chromatography (mu-HPLC) and the effects of applied voltage, stationary phase and concentration of ion-pairing agent (trifluoroacetic acid, TFA) on the gradient p-CEC were also studied. This separation was performed rapidly on a new CEC instrument Trisep 2010 GV. The results showed that the retention mechanism of proteins in p-CEC mode is based on both chromatographic partitioning and electrophoretic migration. The results also demonstrated that p-CEC may have great potential for fast and efficient separation of proteins.
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PMID:[Separation of proteins by gradient pressurized capillary electrochromatography]. 1649 3

Monodisperse, 3.0 microm non-porous hydrophilic poly (glycidylmethacrylate-co-ethylenedimethacrylate) particles were prepared by an one-step swelling and polymerization method. The particles were modified to be a strong cation exchange (SCX) stationary phase for high performance liquid chromatography (HPLC) in the following steps. First, the particles were completely hydrolyzed. Second, the hydrolyzed particles were treated with epichlorhydrin followed by another hydrolysis of the newly introduced epoxide groups. Third, the particles were reacted with chlorosulfonic acid. The SCX stationary phase was evaluated in light of the ion exchange property, separability and hydrophilicity on the separation and retention of proteins in detail. Four proteins were quickly separated in 1.0 min with linear gradient elution using the synthesized SCX stationary phase. It was found that it followed ion exchange chromatographic (IEC) retention mechanism. The SCX resin was used for the fast purification of lysozyme from egg white and cytochrome-C from pig heart in 3.0 min with only one step. The results obtained were satisfactory.
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PMID:[Preparation of strong cation exchange packings based on monodisperse hydrophilic non-porous resins and their application for fast separation of proteins]. 1683 Apr 58

A new class of receptor is described that can selectively bind to the solvent exposed surface of proteins such as cytochrome c and lysozyme with low micromolar affinity over cytochrome c551, alpha-lactalbumin, myoglobin and RNase A, under physiologically relevant conditions (5 mM phosphate, pH 7.4). The use of anthracene as a hydrophobic scaffold allows the receptor to act as a selective chemosensor via fluorescence quenching or FRET. The study reveals that co-operative electrostatic interactions over a large surface area dominate binding. Further investigations reveal that the receptor binds to the solvent exposed heme edge of cytochrome c inhibiting its reaction with small reducing agents and validating the strategy for the disruption of protein function.
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PMID:Recognition of solvent exposed protein surfaces using anthracene derived receptors. 1720 71

The interactions between lysozyme-imprinted hydrogel and their template protein were studied using adsorption measurements, competitive adsorption experiments, and isothermal titration calorimetry (ITC). The results were compared to the interactions between the imprinted polymer and a reference protein, cytochrome c. Experimental adsorption isotherms and competitive adsorption studies detected better affinity and higher capacity of the imprinted polymer toward the template protein. Moreover, analysis of ITC data identified major differences in the binding enthalpy of lysozyme when the imprinted and the non-imprinted polymers were compared. On the other hand, cytochrome C did not exhibit any major changes in the adsorption enthalpy when comparing the imprinted and the non-imprinted polymers. This is the first thermodynamic evidence for the creation of new binding sites in the process of protein imprinting.
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PMID:Study of the interactions between protein-imprinted hydrogels and their templates. 1744 67

We report a study of the interactions of proteins with monolayers of phospholipids (D/L-alpha-dipalmitoyl phosphatidylcholine and L-alpha-dilauroyl phosphatidylcholine) spontaneously assembled at an interface between an aqueous phase and a 20-microm-thick film of a nematic liquid crystal (4'-pentyl-4-cyanobiphenyl). Because the orientation of the liquid crystal is coupled to the organization of the lipids, specific interactions between phospholipase A2 and the lipids (binding and/or hydrolysis) that lead to reorganization of the lipids are optically reported (using polarized light) as dynamic orientational transitions in the liquid crystal. In contrast, nonspecific interactions between proteins such as albumin, lysozyme, and cytochrome-c and the lipid-laden interface of the liquid crystal are not reported as orientational transitions in the liquid crystals. Concurrent epifluorescence and polarized light imaging of labeled lipids and proteins at the aqueous-liquid crystal interface demonstrate that spatially patterned orientations of the liquid crystals observed during specific binding of phospholipase A2 to the interface, as well as during the subsequent hydrolysis of lipids by phospholipase A2, reflect the lateral organization (micrometer-sized domains) of the proteins and lipids, respectively, at the aqueous-liquid crystal interface.
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PMID:Coupling of the orientations of thermotropic liquid crystals to protein binding events at lipid-decorated interfaces. 1759 19

A computational framework based on the Finite Element Method is presented to calculate the normal modes and mechanical response of proteins and their supramolecular assemblies. Motivated by elastic network models, proteins are treated as continuum elastic solids with molecular volume defined by their solvent-excluded surface. The discretized Finite Element representation is obtained using a surface simplification algorithm that facilitates the generation of models of arbitrary prescribed spatial resolution. The procedure is applied to a mutant of T4 phage lysozyme, G-actin, syntenin, cytochrome-c', beta-tubulin, and the supramolecular assembly filamentous actin (F-actin). Equilibrium thermal fluctuations of alpha-carbon atoms and their inter-residue correlations compare favorably with all-atom-based results, the Rotational-Translational Block procedure, and experiment. Additionally, the free vibration and compressive buckling responses of F-actin are in quantitative agreement with experiment. The proposed methodology is applicable to any protein or protein assembly and facilitates the incorporation of specific atomic-level interactions, including aqueous-electrolyte-mediated electrostatic effects and solvent damping. The procedure is equally applicable to proteins with known atomic coordinates as it is to electron density maps of proteins, protein complexes, and supramolecular assemblies of unknown atomic structure.
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PMID:A finite element framework for computation of protein normal modes and mechanical response. 1797 33

The red flour beetle, Tribolium castaneum, is an established genetically tractable model insect for evolutionary and developmental studies. Therefore, it may also represent a valuable model for comparative analysis of insect immunity. Here, we used the suppression subtractive hybridization method to identify Tribolium genes that are transcriptionally induced in response to injection of crude lipopolysaccharide (LPS). Determined genes encode proteins that share sequence similarities with counterparts from other insects known to mediate sensing of infection (e.g. Toll and PGRP) or to represent potential antimicrobial effectors (e.g. ferritin, c-type lysozyme, serine proteinase inhibitors, and defensins). Especially significant is the identification of thaumatin-like peptides, representing ancient antifungal peptides originally reported from plants, that are absent from the genomes of many other insects such as Drosophila, Anopheles, and Apis. We produced recombinant thaumatin-1 in bacteria and we found that it represents an antimicrobial peptide against filamentous fungi in Tribolium. Additionally, septic injury induces expression of genes involved in stress adaptation (e.g. heat-shock proteins) or insecticide resistance (e.g. cytochrome P450s) in Tribolium, suggesting that there may be crosstalk between the immune and stress responses.
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PMID:Beetle immunity: Identification of immune-inducible genes from the model insect Tribolium castaneum. 1798 28

1-Butyl-3-methylimidazolium tetrafluoroborate ionic liquids (1B-3MI-TFB ILs) were employed as a coating material and BGE in CE for simultaneous separation of basic and acidic proteins such as lysozyme, cytochrome C, ribonuclease A, albumin, and alpha-lactalbumin. 1B-3MI-TFB ILs effectively reversed the surface charges on the capillary inner surface, preventing the adsorption of positively charged proteins onto the silica surface, as well as associated with proteins, thus benefiting the separation efficiencies and reproducibility. Consequently, simultaneous baseline separation of five proteins was achieved within 14 min by using 10 mM of 1B-3MI-TFB ILs as dynamic coating and the only running electrolyte at the voltage of +20 kV. The proposed coating technique is simple, less time-consuming, reproducible, and also stable enough for proteins separation without the need of additives. Symmetrical peaks with efficiencies up to 670,000 plates/m were obtained. Recoveries of proteins with RSD (for migration times) of 0.23-0.42% (run-to-run) and 2.5-3.8% (day-to-day) were achieved, respectively. The applicability of the proposed method in proteins separation was evaluated by the separation of egg white samples.
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PMID:Simultaneous separation of basic and acidic proteins using 1-butyl-3-methylimidazolium-based ion liquid as dynamic coating and background electrolyte in capillary electrophoresis. 1844 60

A novel purification technique is proposed which employs affinity-ligand-modified liposomes to specifically purify bioactive macromolecules from solution. This process is demonstrated with avidin as the model biomolecule and biotin as the affinity ligand. Biotin is covalently bound to the surface of small unilamellar vesicles composed of dimyristoyl phosphatidylcholine (DMPC) and dimyristoyl phosphatidylethanolamine (DMPE). The number of accessible binding sites on the liposomes is determined by titration with avidin, and the kinetics of binding are evaluated by monitoring the concentration of free avidin in solution after the addition of biotinylated liposomes. The specificity of the process is determined by following the affinity binding of avidin to biotinylated liposomes in the presence of model impurities (i.e., lysozyme and cytochrome C). Liposome-bound avidin is separated from the impurities by ultrafiltration through a membrane which retains the liposomes.
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PMID:Protein purification by affinity binding to unilamellar vesicles. 1858 98


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