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White Lysozyme (white + lysozyme)
Kinds of White Lysozyme Selected AbstractsGrowth of large protein crystals by a large-scale hanging-drop methodJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2010Keisuke Kakinouchi A method for growing large protein crystals is described. In this method, a cut pipette tip is used to hang large-scale droplets (maximum volume 200,µl) consisting of protein and precipitating agents. A crystal grows at the vapor,liquid interface; thereafter the grown crystal can be retrieved by droplet,droplet contact both for repeated macroseeding and for mounting crystals in a capillary. Crystallization experiments with peroxiredoxin of Aeropyrum pernix K1 (thioredoxin peroxidase, ApTPx) and hen egg white lysozyme demonstrated that this large-scale hanging-drop method could produce a large-volume crystal very effectively. A neutron diffraction experiment confirmed that an ApTPx crystal (6.2,mm3) obtained by this method diffracted to beyond 3.5,Å resolution. [source] A simple technique to convert sitting-drop vapor diffusion into hanging-drop vapor diffusion by solidifying the reservoir solution with agaroseJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2009Tae Woong Whon A simple protocol to convert sitting-drop vapor-diffusion plating into a hanging-drop vapor-diffusion experiment in protein crystallization is reported. After making a sitting-drop plate, agarose solution was added to solidify the reservoir solution, and the plates were incubated upside down. Crystallization experiments with hen egg white lysozyme, thaumatin and glucose isomerase showed that the `upside-down sitting-drop' method could produce single crystals with all the benefits of the hanging-drop crystallization method. [source] Soluble oligomers from a non-disease related protein mimic A,-induced tau hyperphosphorylation and neurodegenerationJOURNAL OF NEUROCHEMISTRY, Issue 2 2007Marcelo N. N. Vieira Abstract Protein aggregation and amyloid accumulation in different tissues are associated with cellular dysfunction and toxicity in important human pathologies, including Alzheimer's disease and various forms of systemic amyloidosis. Soluble oligomers formed at the early stages of protein aggregation have been increasingly recognized as the main toxic species in amyloid diseases. To gain insight into the mechanisms of toxicity instigated by soluble protein oligomers, we have investigated the aggregation of hen egg white lysozyme (HEWL), a normally harmless protein. HEWL initially aggregates into ,-sheet rich, roughly spherical oligomers which appear to convert with time into protofibrils and mature amyloid fibrils. HEWL oligomers are potently neurotoxic to rat cortical neurons in culture, while mature amyloid fibrils are little or non-toxic. Interestingly, when added to cortical neuronal cultures HEWL oligomers induce tau hyperphosphorylation at epitopes that are characteristically phosphorylated in neurons exposed to soluble oligomers of the amyloid-, peptide. Furthermore, injection of HEWL oligomers in the cerebral cortices of adult rats induces extensive neurodegeneration in different brain areas. These results show that soluble oligomers from a non-disease related protein can mimic specific neuronal pathologies thought to be induced by soluble amyloid-, peptide oligomers in Alzheimer's disease and support the notion that amyloid oligomers from different proteins may share common structural determinants that would explain their generic cytotoxicities. [source] On the possibility of using polycrystalline material in the development of structure-based generic assaysACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2009Marc Allaire The discovery of ligands that bind specifically to a targeted protein benefits from the development of generic assays for high-throughput screening of a library of chemicals. Protein powder diffraction (PPD) has been proposed as a potential method for use as a structure-based assay for high-throughput screening applications. Building on this effort, powder samples of bound/unbound states of soluble hen-egg white lysozyme precipitated with sodium chloride were compared. The correlation coefficients calculated between the raw diffraction profiles were consistent with the known binding properties of the ligands and suggested that the PPD approach can be used even prior to a full description using stereochemically restrained Rietveld refinement. [source] Novel Isoelectric Precipitation of Proteins in a Pressurized Carbon Dioxide-Water-Ethanol SystemBIOTECHNOLOGY PROGRESS, Issue 4 2004Xiang-Ming Qi A novel isoelectric precipitation of proteins in a pressurized carbon dioxide,water,ethanol system was developed where carbon dioxide was used as a volatile acid. The pH,pressure curves of the system with the absence and presence of proteins were investigated. By introducing the pressurized carbon dioxide to a solution containing protein, the pH value in the solution was decreased to the isoelectric region of the model protein BSA. Addition of ethanol could lower the buffer capacity of the protein, which made the precipitation concentration of protein go beyond the limits in a system without ethanol and well exploited the application field of the technique. In addition, ethanol in solution played the role of aiding precipitation in the process. Another model protein, hen egg white lysozyme, was also studied but could not be precipitated in the above system. All of these phenomena prove that isoelectric precipitation is the key point in the pressurized carbon dioxide,water,ethanol system. [source] Studies on the Refolding of Egg White Lysozyme Denatured by Urea Using "Phase Diagram" Method of FluorescenceCHINESE JOURNAL OF CHEMISTRY, Issue 12 2007Liu-Jiao BIAN Abstract The refolding of reduced and non-reducing egg white lysozymes in a urea solution was studied by a "phase diagram" method of fluorescence. The result showed that in the refolding of the reduced egg white lysozyme, an intermediate state of an egg white lysozyme exists at the urea concentrations in a final renaturation solution being about 4.5 mol/L, their refolding follows a three-state model; while in the refolding of the non-reducing egg white lysozyme, two intermediate states exist at the urea concentrations being separately 4.0 and 2.5 mol/L, and their refolding follows a four-state model. Through the comparison between the unfolding and refolding of an egg white lysozyme in the urea solution, it was found that both of the refolding of reduced and non-reducing egg white lysozyme molecules was irreversible to their unfolding in the urea solution. Finally, a suggested refolding was separately presented for the reduced and non-reducing egg white lysozymes in the urea solution. [source] Concentration Of Egg White Lysozyme In The Serum Of Healthy Subjects After Oral AdministrationCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2002Seiichi Hashida SUMMARY 1. While the egg white lysozyme preparation ER0068 (Neuzym®; Eisai, Tokyo, Japan) is widely used clinically, no studies have been performed on its pharmacokinetic properties at clinically relevant doses. In the present study, we used a highly sensitive two-site enzyme immunoassay in order to determine the pharmacokinetic properties of egg white lysozyme after oral administration of two doses within the clinical range, paying particular attention to the effects of food intake. 2. A total of 22 healthy male subjects aged 20,45 years participated in the study. All subjects had been screened for egg white allergy and non-specific lysozyme inhibitors in their serum. Subjects who received 90 mg ER0068 after an overnight fast reached a maximum serum concentration of 1700 pg/mL within 1 h, compared with non-detectable levels in untreated controls. In a second experiment, subjects received 30 and 90 mg ER0068 after an overnight fast and 90 mg in the non-fasted state and exhibited maximum serum levels of 37, 360 and 49 pg/mL, respectively. Egg white lysozyme concentrations in serum returned to undetectable levels after a maximum of 48 h. 3. We conclude that clinically relevant concentrations of egg white lysozyme are absorbed in significant amounts, despite its high molecular weight. However, food intake considerably reduces the amount of enzyme absorbed. [source] Re-evaluation of intramolecular long-range electron transfer between tyrosine and tryptophan in lysozymesFEBS JOURNAL, Issue 17 2003Evidence for the participation of other residues One-electron oxidation of six different c-type lysozymes from hen egg white, turkey egg white, human milk, horse milk, camel stomach and tortoise was studied by gamma- and pulse-radiolysis. In the first step, one tryptophan side chain is oxidized to indolyl free radical, which is produced quantitatively. As shown already, the indolyl radical subsequently oxidizes a tyrosine side chain to the phenoxy radical in an intramolecular reaction. However this reaction is not total and its stoichiometry depends on the protein. Rate constants also vary between proteins, from 120·s,1 to 1000·s,1 at pH 7.0 and room temperature [extremes are hen and turkey egg white (120·s,1) and human milk (1000·s,1)]. In hen and turkey egg white lysozymes we show that another reactive site is the Asn103,Gly104 peptidic bond, which gets broken radiolytically. Tryptic digestion followed by HPLC separation and identification of the peptides was performed for nonirradiated and irradiated hen lysozyme. Fluorescence spectra of the peptides indicate that Trp108 and/or 111 remain oxidized and that Tyr20 and 53 give bityrosine. Tyr23 appears not to be involved in the process. Thus new features of long-range intramolecular electron transfer in proteins appear: it is only partial and other groups are involved which are silent in pulse radiolysis. [source] Studies on the Refolding of Egg White Lysozyme Denatured by Urea Using "Phase Diagram" Method of FluorescenceCHINESE JOURNAL OF CHEMISTRY, Issue 12 2007Liu-Jiao BIAN Abstract The refolding of reduced and non-reducing egg white lysozymes in a urea solution was studied by a "phase diagram" method of fluorescence. The result showed that in the refolding of the reduced egg white lysozyme, an intermediate state of an egg white lysozyme exists at the urea concentrations in a final renaturation solution being about 4.5 mol/L, their refolding follows a three-state model; while in the refolding of the non-reducing egg white lysozyme, two intermediate states exist at the urea concentrations being separately 4.0 and 2.5 mol/L, and their refolding follows a four-state model. Through the comparison between the unfolding and refolding of an egg white lysozyme in the urea solution, it was found that both of the refolding of reduced and non-reducing egg white lysozyme molecules was irreversible to their unfolding in the urea solution. Finally, a suggested refolding was separately presented for the reduced and non-reducing egg white lysozymes in the urea solution. [source] | |||||||||||||