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)

Gaseous CO2 was used as an antisolvent to induce the fractional precipitation of alkaline phosphatase, insulin, lysozyme, ribonuclease, trypsin, and their mixtures from dimethylsulfoxide (DMSO). Compressed CO2 was added continuously and isothermally to stationary DMSO solutions (gaseous antisolvent, GAS). Dissolution of CO2 was accompanied by a pronounced, pressure-dependent volumetric expansion of DMSO and a consequent reduction in solvent strength of DMSO towards dissolved proteins. View cell experiments were conducted to determine the pressures at which various proteins precipitate from DMSO. The solubility of each protein in CO2-expanded DMSO was different, illustrating the potential to separate and purify proteins using gaseous antisolvents. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE) was used to quantify the separation of lysozyme from ribonuclease, alkaline phosphatase from insulin, and trypsin from catalase. Lysozyme biological activity assays were also performed to determine the composition of precipitates from DMSO initially containing lysozyme and ribonuclease. SDS-PAGE characterizations suggest that the composition and purity of solid-phase precipitated from a solution containing multiple proteins may be accurately controlled through the antisolvent's pressure. Insulin, lysozyme, ribonuclease, and trypsin precipitates recovered substantial amounts of biological activity upon redissolution in aqueous media. Alkaline phosphatase, however, was irreversibly denaturated. Vapor-phase antisolvents, which are easily separated and recovered from proteins and liquid solvents upon depressurization, appear to be a reliable and effective means of selectively precipitating proteins.
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PMID:Protein purification with vapor-phase carbon dioxide. 1009 36

Lysozyme was encapsulated in biodegradable polymer microspheres which were precipitated from an organic solution by spraying the solution into carbon dioxide. The polymer, either poly(l-lactide) (l-PLA) or poly(DL-lactide-co-glycolide) (PGLA), in dichloromethane solution with suspended lysozyme was sprayed into a CO2 vapor phase through a capillary nozzle to form droplets which solidified after falling into a CO2 liquid phase. By delaying precipitation in the vapor phase, the primary particles became sufficiently large, from 5 to 70 microm, such that they could encapsulate the lysozyme. At an optimal temperature of -20 degrees C, the polymer solution mixed rapidly with CO2, and the precipitated primary particles were sufficiently hard such that agglomeration was markedly reduced compared with higher temperatures. More uniform particles were formed by flowing CO2 at high velocity in a coaxial nozzle to mix the droplets at the CO2 vapor-liquid interface. This process offers a means to produce encapsulated proteins in poly(DL-lactide-co-glycolide) microspheres without earlier limitations of massive polymer agglomeration and limited protein solubility in organic solvents.
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PMID:Encapsulation of lysozyme in a biodegradable polymer by precipitation with a vapor-over-liquid antisolvent. 1035 May 2

Cell-free lung lavage fluid (LLF) from healthy normal rats killed phase I (wild-type, virulent) Bordetella pertussis at 37 degrees C in vitro. B. parapertussis was also killed by the LLF, but phase IV (avirulent mutant) B. pertussis and some other common bacterial species, including B. bronchiseptica, were not. Transmission electron microscopy of thin sections of the phase I B. pertussis showed extensive structural damage and cell lysis. None of the other mammalian species tested had LLF with bactericidal activity against B. pertussis as high as that of the rat. Rats killed with halothane yielded LLF with higher bactericidal activity than when CO2 was used. Ultracentrifugation of LLF at 55,000 g gave a surfactant (pellet) fraction that had c. 95% of the bactericidal activity and which was biochemically distinct from the 5% of activity in the supernate fraction. Phospholipids and fatty acids appeared to be involved in LLF bactericidal activity, but not complement or lysozyme. Arachidonic acid was the most active of the fatty acids tested. Artificial surfactant, as used in premature infants, had no bactericidal effect on B. pertussis.
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PMID:Bactericidal activity of rat lung lavage fluid against Bordetella pertussis. 1040 14

Prosthetic valve endocarditis may be reduced by the local delivery of antibacterial proteins from the Dacron sewing ring of a prosthetic heart valve. Dacron discs were treated with a carbon dioxide gas plasma to improve the hydrophilicity and thereby enabling homogeneous impregnation with gelatin type B. The gelatin samples were cross-linked to different degrees using various amounts of water-soluble carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Lysozyme, a model protein for antibacterial proteins, was loaded into (non)-cross-linked gelatin gels incorporated in Dacron, or adsorbed onto non-treated and gas plasma-treated Dacron. The in vivo lysozyme release was measured after subcutaneous implantation of lysozyme-loaded samples in rats. The lysozyme content of the samples, and the lysozyme level of the surrounding tissue were determined at different explantation times (ranging from 6 h up to 1 week). For cross-linked gelatin gels, the lysozyme tissue level was elevated up to 2 days after implantation. In vitro release was measured using agarose medium or phosphate buffer. Lysozyme release in buffer solution under sink conditions was in good agreement with the in vivo lysozyme release profiles, and therefore considered a good model to describe in vivo release characteristics. The release was modelled with a solution of Fick's second law of diffusion using the appropriate boundary conditions. In this way the lysozyme concentration in the gel and the surrounding tissue as a function of time and distance was obtained. The presence of cross-linked gelatin in Dacron did lead to an increased uptake of lysozyme and a delayed release during 30 h after implantation, whereas a burst release took place from Dacron, gas plasma-treated Dacron, or Dacron containing non-cross-linked gelatin.
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PMID:In vivo and in vitro release of lysozyme from cross-linked gelatin hydrogels: a model system for the delivery of antibacterial proteins from prosthetic heart valves. 1082 64

The solution enhanced dispersion by supercritical fluid (SEDS) process was used to evaluate the effect of the processing variables on the biological and physicochemical characteristics of lysozyme protein particles produced from an organic solution of dimethylsulfoxide (DMSO) using an experimental design procedure. The processing variables were temperature, pressure, solution concentration and the flow-rates of supercritical carbon dioxide and a protein solution. Solutions of hen egg lysozyme (0.5-1%, w/v) in DMSO were dispersed using supercritical carbon dioxide as the antisolvent, and particles precipitated in a particle formation vessel. The morphology, particle size and size distribution and biological activity of the protein were determined. The precipitates were also examined with high sensitivity differential scanning calorimetry (HSDSC) and high-performance cation-exchange chromatography. The amount of residual DMSO was determined using headspace gas chromatography. Particle size measurements showed the precipitates to be agglomerates with primary particles of size 1-5 microm, containing <20 ppm of residual solvent. The activity of the precipitates varied between 44 and 100% depending on the experimental conditions. The similarity of HSDSC data for unprocessed and processed samples indicated that the SEDS process does not cause major denaturation of lysozyme when prepared from DMSO solutions. By optimising of working conditions, the SEDS process can produce micron-sized particles of lysozyme with minimal loss of biological activity.
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PMID:Supercritical fluid processing of proteins. I: lysozyme precipitation from organic solution. 1104 30

We report on the use of a new supercritical carbon dioxide-assisted aerosolization coupled with bubble drying technology to prepare stabilized, dry, finely divided powders from aqueous protein formulations. In this study, the feasibility of this new technology was tested using two model proteins, lysozyme and lactate dehydrogenase (LDH). In the absence of excipients, lysozyme was observed to undergo perturbations of secondary structure observed by solid-state infrared spectroscopy. In the presence of sucrose, this unfolding was minimized. Lysozyme did not, however, undergo irreversible loss of activity, as all lysozyme powders generated by supercritical CO(2)-assisted aerosolization (with or without excipients) regained almost complete activity on reconstitution. The more labile LDH suffered irrecoverable loss of activity on reconstituting after supercritical CO(2)-assisted aerosolization and bubble drying in the absence of carbohydrate stabilizers. LDH could be stabilized throughout the nebulization, drying, and rehydration processes with the addition of sucrose, and almost complete preservation of activity was achieved with the further addition of a surface active agent, such as Tween 20, to the aqueous formulation prior to processing.
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PMID:Dry powders of stable protein formulations from aqueous solutions prepared using supercritical CO(2)-assisted aerosolization. 1135 79

During its normal life cycle, Diplostomum spathaceum cercariae attach to and invade fish intermediate hosts. They are also known to attach to various other aquatic animals in response to water currents, touch and carbon dioxide. The purpose of this study was to identify the specific stimuli used by D. spathaceum cercariae to recognise the appropriate fish host. We characterised the host cues which stimulate them to remain on the host (enduring contact) and to penetrate the skin. Cercariae were exposed to animal skin tissues and fish skin surface mucus, their extracts and chemical modifications integrated into agar or offered via membrane filters. Enduring contact was stimulated by hydrophilic extracts Mr<3kDa, which were sensitive to oxidation of carbohydrates. The stimulating cues are probably small molecular carbohydrates, as monosaccharides stimulated enduring contacts, but amino acids, urea, electrolytes and peptides did not. Penetration was stimulated by hydrophilic macromolecules, Mr>30kDa, and by lipids. The hydrophilic stimuli were protease resistant and precipitable with Alcian blue and they were sensitive to alkaline cleavage, to digestion with lysozyme and neuraminidase as well as to oxidation of sialic acids. They were considered to be glycoproteins with O-glycosidically linked carbohydrate chains and bound sialic acids as signal structures. The lipophilic penetration stimuli were contained exclusively in the fatty acid fractions, and the stimulating characteristics of these fatty acids resembled the stimulating penetrations in other cercarial species. Diplostomum spathaceum cercariae respond to a unique profile of cues in their sequence of host-recognition phases. These cues differ from those used in other fish parasites studied to date and underline the diversity of fish recognition strategies.
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PMID:Diplostomum spathaceum cercariae respond to a unique profile of cues during recognition of their fish host. 1211 97

The launch of molecules from liquid surfaces in a time of flight mass spectrometer has been investigated using different sample preparation techniques, and by exposing the liquid samples to two different laser wavelengths, 337 nm from a N2 ultraviolet laser and 10.6 microm from a CO2 infrared laser. The molecules were detected with cryodetectors measuring the energy of the individual molecules. We present insulin and lysozyme results from samples introduced into the vacuum through a micromachined silicon injector, and from samples consisting of a glycerol droplet deposited directly on the sample holder at the high voltage stage of the ion optics.
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PMID:Detecting single molecules launched from liquid surfaces in a time-of-flight mass spectrometer using ultraviolet and infrared lasers. 1216 3

Aqueous solutions of hen egg lysozyme (3% w/v) were dispersed and precipitated by a homogenous mixture of supercritical carbon dioxide-ethanol using the Solution Enhanced Dispersion by Supercritical fluid (SEDS) process. The effects of different working conditions, such as temperature, pressure and the flow rates of the solution and ethanol, on the particle-formation process were studied. The morphology, particle size and size distribution and biological activity of the protein were determined. The precipitates were examined with high-sensitivity differential scanning calorimetry (HSDSC) and high-performance cation-exchange chromatography. Particle size measurements showed the precipitates to be aggregates with primary particles of size 1-5 microm. The similarity of HSDSC data for unprocessed and processed samples indicated that the different physical forces that stabilise the native form of lysozyme are unchanged after SEDS processing. From FT-Raman spectroscopic studies secondary structural changes were observed in certain SEDS-produced lysozyme, with most processed samples displaying a slightly more disordered secondary structure than the unprocessed sample. However, SEDS samples produced at 200 bar and 40 degrees C exhibited negligible disturbance. Thus the SEDS process utilising aqueous solution was able to bring about size reduction of lysozyme with minimal loss of biological activity.
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PMID:Supercritical fluid processing of proteins: lysozyme precipitation from aqueous solution. 1263 10

The protein lysozyme has been precipitated as amorphous nanoparticles from a DMSO solution using dense carbon dioxide as antisolvent, by applying the so-called gas antisolvent recrystallization technique in a 400-mL precipitator. The objective is to investigate the possibility of tuning the particle properties by changing the key process parameters, namely, antisolvent addition rate, initial solute concentration, and temperature. It is shown that none of these operating parameters has a major effect on the average particle size or the particle size distribution. The former is mostly between 200 and 300 nm and exhibits no evident trend. The latter is always unimodal and rather narrow and exhibits increasing agglomeration at higher temperature and initial solute concentration. Up to 75% of the protein activity measured in the starting crystalline material is retained by the precipitated amorphous nanoparticles. The present experimental results compare well with data about the same system obtained in a different experimental setup, which were previously reported in the literature, thus pointing at the reproducibility and robustness of GAS antisolvent recrystallization. Moreover, these are consistent with the theoretical understanding of gas antisolvent recrystallization as achieved by using a recently developed model of the process.
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PMID:Precipitation of lysozyme nanoparticles from dimethyl sulfoxide using carbon dioxide as antisolvent. 1267


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