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)

Five stains of Bifidobacterium bifidum (ATCC 11863 and 29591, and NCFB 1453, 1454, 1455) were examined for production of bacteriocins in MRS broth with 0.05% cysteine. Only strain NCFB 1454 excreted a bacteriocin into the broth: it was designated bifidocin B. Bifidocin B was sensitive to several proteolytic enzymes (protease IV, pronase E, protease XVII, proteinase K, trypsin, alpha-chymotrypsin, papain, and pepsin), but was resistant to catalase, peroxidase, lipase, lysozyme, cellulase, ribonuclease A, and amylases. It was also resistant to organic solvents such as ethyl alcohol, acetone, hexane, chloroform, methanol, and ether, and to heating at 90 degrees C for 15, 30, and 60 min or at 121 degrees C for 15 min. Bifidocin B remained active after storage at -20 or -7 degrees C for 3 months and retained biological activity after exposure to pH values of 2 to 10. Bifidocin B was active against some food-borne pathogens and food spoilage bacteria such as Listeria, Enterococcus, Bacillus, Lactobacillus, Leuconostoc, and Pediococcus species but was not active against the other gram-positive and gram-negative bacteria tested. Bifidocin B was produced during exponential phase, reaching a maximum activity of 3,200 AU/ml at early stationary phase. Bifidocin B had a molecular mass of about 3.3 kDa as analyzed by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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PMID:Characterization and antimicrobial spectrum of bifidocin B, a bacteriocin produced by Bifidobacterium bifidum NCFB 1454. 970 52

Crystallization trials using three polyoxyethylene surfactants as precipitating agents are described. Of the eight soluble proteins screened, five were successfully crystallized at the first attempt. These included lysozyme, catalase, ferritin, ribonuclease A and ubiquitin. Further work suggested that these surfactants could also be suitable for cryo-crystallographic analysis of crystals. At the concentrations used in the crystallization trials [10-40%(v/v)], they are capable of promoting the formation of non-crystalline glasses at cryogenic temperatures (77K). This would facilitate crystal mounting and allow the minimization of crystal irradiation damage. Results from this study also suggest that proteins remain stable at high concentrations of these surfactants [40%(w/v)] and over long time periods (>1 month). A number of membrane proteins were also screened for crystallization. These included photosystems I and II and light harvesting complexes I and II from spinach and bacteriorhodopsin from Halobacterium halobium++. The trial s were unsuccessful both in the absence and presence of heptane-1,2,3-triol and over a wide range of surfactant concentrations.
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PMID:A novel approach for the crystallization of soluble proteins using non-ionic surfactants. 986 32

A quick and simple method has been developed for the recovery of proteins from water-in-oil microemulsions (w/o-MEs), which is needed to further the use of liquid-liquid extraction in bioseparations. By adding a small portion (0.1 v/v or less) of cosurfactant (e.g., 1-alkanol) to w/o-ME solution, proteins were readily expelled, sometimes as solids, while most or all of the surfactant (Aerosol OT) remained in solution. The release of proteins increased with the further addition of cosurfactant and was greater when the molar ratio of protein to w/o-ME or fractional occupancy (f) was high. However, protein expulsion was also significant when f was small. The addition of cosurfactant released ribonuclease, lysozyme, alpha-chymotrypsin, pepsin, bovine serum albumin (BSA), and catalase from w/o-ME solution, but the expulsion was greater for BSA relative to chymotrypsin and lysozyme. Protein expulsion also increased with cosurfactant chain length for the homologous series of 1-alkanols starting at 1-butanol; however, water was also coexpelled in significant amounts. An exception to the latter rule was 1-butanol, which readily promoted the release of protein, but not encapsulated water. The addition of 1-butanol to a w/o-ME solution containing alpha-chymotrypsin and BSA selectively released the former protein, with chymotryptic activity occurring in the recovered protein. Possible mechanisms for the cosurfactant-mediated release of protein are discussed. Copyright 1998 John Wiley & Sons, Inc.
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PMID:Expulsion of proteins from water-in-oil microemulsions by treatment with cosurfactant 1009 72

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

As part of a study of protein denaturation in foam we have measured the surface tension and the changes in protein structure occurring at the interface for lysozyme, pepsin, BSA, YADH, IgG, and catalase. The apparent CMC values were found to be dependent on the size and rigidity of the molecule. The variability of protein damage at a gas-liquid interface in foam was assessed using these proteins. The foams were produced under controlled conditions in a bubble column and were found to induce conformational changes in the protein molecules, but no fragmentation or disassociation of subunits occurred. Tertiary structural changes were detected in all the proteins studied, with some proteins forming aggregates. For pepsin, the secondary structure was also found to be altered. Enzyme solutions were used to determine the degree of biological activity retained after foaming for proteins with different structural characteristics. The more rigid proteins were found to display a low surface activity and a low degree of damage in foam. Pepsin suffered the highest rate of damage, which is thought to be a result of its inability to refold following denaturation. Copyright 1999 Academic Press.
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PMID:Protein Denaturation in Foam. 1041 68

Enterococcus gallinarum strain 012, isolated from the duodenum of ostrich, produced enterocin 012 which is active against Ent. faecalis, Lactobacillus acidophilus, Lact. sake, Listeria innocua, Propionibacterium acidipropionici, Propionibacterium sp., Clostridium perfringens, Pseudomonas aeruginosa and Salmonella typhimurium. One of the four pathogenic strains of Escherichia coli isolated from the intestinal tract of ostrich was inhibited by enterocin 012. No antimicrobial activity was recorded against Bacillus cereus, Cl. sporogenes, Cl. tyrobutyricum, Leuconostoc cremoris, Pediococcus pentosaceus, Staphylococcus carnosus and Streptococcus thermophilus. Enterocin 012 was resistant to treatment with lysozyme, catalase, lipase and papain, but sensitive to Proteinase K, alpha-chymotrypsin, trypsin and pepsin. Treatment of enterocin 012 with gastric juice from the duodenum resulted in a 50% loss of antibacterial activity. Half of the activity was lost when incubated at 80 degrees C for 30 min, or when kept overnight at a pH of 1.0-5.0 and pH 11.0 and 12.0, respectively. Enterocin 012 production started in mid-logarithmic growth and reached a maximum of 800 AU ml-1, but increased further to 1600 AU ml-1 in the stationary growth phase. The peptide is approximately 3.4 kDa in size, as determined after partial purification with Amberlite XAD-1180 and ammonium sulphate precipitation, followed by tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The mechanism of antimicrobial activity against Lact. sake LMG 13558 is bactericidal and caused cell lysis of active growing cells.
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PMID:Enterocin 012, a bacteriocin produced by Enterococcus gallinarum isolated from the intestinal tract of ostrich. 1073 5

A total of 92 enterococci, isolated from the faeces of minipigs subjected to an in vivo feeding trial, were screened for the production of antimicrobial substances. Bacteriocin production was confirmed for seven strains, of which four were identified as Enterococcus faecalis and three as Enterococcus faecium, on the basis of physiological and biochemical characteristics. The bacteriocins produced by the Ent. faecalis strains showed a narrow spectrum of activity, mainly against other Enterococcus spp., compared with those from the Ent. faecium strains showing a broader spectrum of activity, against indicator strains of Enterococcus spp., Listeria spp., Clostridium spp. and Propionibacterium spp. The bacteriocins of all seven Enterococcus strains were inactivated by alpha-chymotrypsin, proteinase K, trypsin, pronase, pepsin and papain, but not by lipase, lysozyme and catalase. The bacteriocins were heat stable and displayed highest activity at neutral pH. The molecular weight of the bacteriocins, as determined by tricine SDS-PAGE, was approximately 3.4 kDa. Only the strains of Ent. faecalis were found to contain plasmids. PCR detection revealed that the bacteriocins produced by Ent. faecium BFE 1170 and BFE 1228 were similar to enterocin A, whereas those produced by Ent. faecium BFE 1072 displayed homology with enterocin L50A and B.
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PMID:Preliminary characterization of bacteriocins produced by Enterococcus faecium and Enterococcus faecalis isolated from pig faeces. 1074 29

A recombinant strain of Aspergillus niger (B1-D), engineered to produce the marker protein hen egg white lysozyme, was investigated with regard to its susceptibility to "oxidative stress" in submerged culture in bioreactor systems. The culture response to oxidative stress, produced either by addition of exogenous hydrogen peroxide or by high-dissolved oxygen tensions, was examined in terms of the activities of two key defensive enzymes: catalase (CAT) and superoxide dismutase (SOD). Batch cultures in the bioreactor were generally found to have maximum specific activities of CAT and SOD (Umg x protein(-1)) in the stationary/early-decline phase. Continuous addition of H2O2 (16 mmole L(-1) h(-1)), starting in the early exponential phase, induced CAT but did not increase SOD significantly. Gassing an early exponential-phase culture with O2 enriched (25 vol%) air resulted in increased activities of both SOD and CAT relative to control processes gassed continuously with air, while gassing the culture with 25 vol% O2 enriched air throughout the experiment, although inducing a higher base level of enzyme activities, did not increase the maximum SOD activity obtained relative to control processes gassed continuously with air. The profile of the specific activity of SOD (U mg CDW(-1)) appeared to correlate with dissolved oxygen levels in processes where no H2O2 addition occurred. These findings indicate that it is unsound to use the term "oxidative stress" to encompass a stress response produced by addition of a chemical (H2O2) or by elevated dissolved oxygen levels because the response to each might be quite different.
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PMID:"Oxidative stress" response in submerged cultures of a recombinant Aspergillus niger (B1-D). 1106 35

In most cases, the presence of an endogenous photosensitizer is a requirement for visible light modification of biomolecules in animal tissues. Riboflavin (RF) is present in all aerobic cells and is a very efficient photosensitizer, presenting a complex photochemistry with a mixed type I-type II mechanisms. Visible light irradiation in the presence of RF diminished the enzymatic activity of horse radish peroxidase (HRP) only when this glyco-enzyme was deglycosilated. In contrast, the activity of catalase is inactivated via singlet oxygen, and that of lysozyme was efficiently inactivated by a mixed type I-type II mechanisms. The reactive species involved in the RF sensitized photoconversion of lysozyme and the aromatic amino acids tryptophan and tyrosine (both free in solution) is discussed. The role of ascorbate and the effect of RF photosensitized processes in biological complex systems, such as the ocular lens and tumoral cell in culture, is analyzed.
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PMID:Effect of visible light on selected enzymes, vitamins and amino acids. 1168 59

The reversible fluorescence labeling of insulin, catalase and lysozyme has been demonstrated. As a derivatizing reagent, dansylaminomethylmaleic acid (DAM) has been used after investigating the precolumn and precapillary derivatization conditions. This reagent (DAM) reacts with the amino groups of proteins via its anhydride in the presence of a suitable dehydrating reagent, which then could be liberated under mild acidic conditions and the native proteins are regenerated. After the derivatization of insulin, catalase and lysozyme with DAM, no peaks of these native proteins were observed while several peaks of the derivatized proteins due to the multiple labeling were observed. However, after the regeneration, increasing amounts of the native proteins were observed as the regeneration period increased. For the lysozyme, the bacteriolytic activity of the enzyme decreased after the derivatization, and only 0.9% of the activity remained. The activity increases by the regeneration, and 95.6% of the bacteriolytic activity of the native enzyme was observed after a 48-h regeneration at pH 2.5 and 40 degrees C.
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PMID:Reversible fluorescence labeling of amino groups of protein using dansylaminomethylmaleic anhydride. 1193 94


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