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 action of certain substances known to induce cellular alterations, or encounted in the oral cavity, on the accumulation of 18F by Streptococcus mutans GS-5 has been investigated. A 62-67% inhibition in the number of 18F atoms bound per mg dry weight of cells could be induced by a 15 min pretreatment with 2.7 X 10(-4) M cetyltrimethylammoniumbromide, 1 X 10(-1) M acetic anhydride, or 7 X 10(-2) M HCl. Plate counts indicated that alteration of the cellular composition rather than viability was responsible for this diminution in 18F accumulation. Prior exposure for 15 min of this organism to 1 M HCHO or 0.1 M NaOH did not alter 18F accumulation. Of the common salts encountered in the oral cavity, CaCl2 enhanced 18F binding. Pretreatment of the assay cells for 15-160 min with 0.1-10 mg/ml of trypsin, pronase, protease, alpha-glucosidase, dextranase, or lactoferrin had no significant effect on the accumulation of 18F. However, pre-exposure of cells for 60 min to 1-10 mg/ml of either amylase or lipase induced a 40-67% inhibition in the binding of 18F, while lysozyme enhanced the binding of 18F by the cells. It would appear then that the binding of 18F by S. mutans may be altered by certain substances encountered in the oral cavity.
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PMID:The action of selected agents on the accumulation of 18F by Streptococcus mutans. 618 42

A very simple, inexpensive procedure for preparing pure plasmid DNA from bacteria is described. In this method, lysozyme-induced spheroplasts are made in presence of 833 micrograms/ml of ethidium bromide which are then lysed by a mixture of Brij 58 and sodium deoxycholate, and the lysate is centrifuged at 48,000 g for 25 min whereby about 99.9% of total chromosomal DNA is pelleted. From the supernatant containing plasmid DNA, the proteins are removed by phenol extraction and the major part of RNA by CaCl2 precipitation, and finally the small amount of residual RNA is removed by RNase treatment. The average yield of pBR322 DNA from 1 liter of amplified culture by this procedure is 2 to 2.5 mg and the preparation is highly pure, containing only about 0.005% of total yield as chromosomal DNA contaminant. Moreover, the substrate activity and the transforming ability of the plasmid DNA prepared by this method remain unaffected.
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PMID:A simple procedure for large-scale preparation of pure plasmid DNA free from chromosomal DNA from bacteria. 635 82

Sorption of three 125I-labeled human proteins (albumin, immunoglobulin G, and lysozyme) to enamel and cementum was investigated. All three proteins sorped most when suspended in 0.0005 M solution of phosphate or calcium chloride where the least competition between solute ions and label occurred. The addition of human serum to labeled proteins caused a decrease in their sorption which could be partially reversed by increasing the concentration of label. Kinetic experiments demonstrated that sorption was dependent on protein concentration and incubation time and that most of the sorption occurred within the first minute of the reaction. In conclusion, the binding of the three labeled proteins was affected by the charge of the solute ions and was dependent on ion concentration and reaction time. Sorption correlated for the most part with the pK values of the proteins and thus lysozyme, the most basic protein, sorped more than immunoglobulin G, which sorped more than albumin. In all cases, cementum bound more basic protein than did enamel. Increased levels of albumin sorption to enamel occurred when the protein was suspended in the CaCl2 solution rather than in phosphate. In addition, based on Scatchard analysis, approximately twice as many potential protein binding sites were found for cementum versus enamel.
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PMID:In vitro sorption of albumin, immunoglobulin G, and lysozyme to enamel and cementum from human teeth. 671 37

The experimental conditions for plasmid transfer and genetic recombination in Staphylococcus aureus and some coagulase-negative staphylococci by protoplast fusion are described. Protoplasts were prepared by treatment with lysostaphin and lysozyme in a buffered medium with 0.7 to 0.8 M sucrose. Regeneration of cell walls was accomplished on a hypertonic agar medium containing succinate and bovine serum albumin. Transfer of plasmids occurred after treatment of the protoplast mixtures with polyethylene glycol (molecular weight, 6,000) not only between strains of the same species but also between parents of different species, although at approximately 100 times lower frequency in the latter case. Recombination of the chromosomal genes in fused protoplasts required simultaneous treatment of the mixed protoplasts with polyethylene glycol and CaCl2. A method was developed for isolation of recombinants after fusion between mutants of S. areus carrying unselectable markers. Antibiotic resistance plasmids were introduced into the parental strains and used as primary markers to detect protoplast fusion. Chromosomal recombinants were found among the clones with both parental plasmids at a high frequency. The method appears to have simple applications in the construction of strains with multiple mutant characters.
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PMID:Plasmid transfer and genetic recombination by protoplast fusion in staphylococci. 700 33

Genetic transfer mediated by spheroplast formation and fusion in Escherichia coli was studied. Recombination did not occur from spheroplasts prepared by the combined glycine and lysozyme-EDTA treatment described by Coetzee et al. (1979). In contrast, when bacteria were exposed to a sub-inhibitory concentration of polymyxin B (0.5 microgram/ml) during the spheroplast generation phase, recombinants arose at frequencies of 1 x 10(-8) to 2.6 x 10(-8). The incidence of genetic transfer was further increased by adding 0.01 M CaCl2 to the polyethylene glycol fusion mixture (from 9 x 10(-7) to 9 x 10(-8). Finally, when the effects of both polymyxin B and calcium chloride were combined recombinants arose at frequencies of 3.4 x 10(-6) to 7.3 x 10(-7). These findings suggest that the detergent-like action of polymyxin B in removing a large part of the outer membrane enhances plasma membrane availability where fusion can take place.
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PMID:Genetic recombination by spheroplast fusion in Escherichia coli K12. 829 82

High molecular weight (HMW) and low molecular weight (LMW) heparins affected superoxide ion production and degranulation by polymorphonuclear leukocytes (PMNL) isolated from either chronic hemodialyzed patients or healthy controls. Low concentrations in HMW-heparin, below 1.76 aXa IU/ml for patients and 1.34 aXa IU/ml for controls, increased O2- production started by phorbol myristate acetate. High concentrations above these values decreased it. Increasing LMW-heparin concentrations constantly decreased O2- production using the same stimulus. Myeloperoxidase (MPO) released by PMNL was found to be significantly HMW- and LMW-heparins dose-dependent. The addition of calcium chloride significantly increased MPO release. Lactoferrin release was not dose-dependent of HMW- or LMW-heparins. However, an increase of the percentage of positive responses for lactoferrin release was observed in the simultaneous presence of HMW-heparin and CaCl2 compared to HMW-heparin alone. Lysozyme release was also not dose-dependent of HMW- or LMW-heparins. An increase of the percentage of positive responses for lysozyme release was observed in the presence of CaCl2 alone compared to HMW-heparin.
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PMID:The effects of high molecular weight- and low molecular weight-heparins on superoxide ion production and degranulation by human polymorphonuclear leukocytes. 838 63

Cellular localization of cytochrome (cyt) c550, a low potential, c-type monoheme cytochrome, in a thermophilic cyanobacterium Synechococcus vulcanus was investigated by systematic fractionation of the cells followed by its enzymatic and immunological detection. While cyt c-553, a soluble cyt that donates an electron to P700, was detected in the supernatant of osmotic disruption of lysozyme-treated cells, cyt c550 was detected only in the thylakoid membrane fraction, being tightly bound to thylakoids, and its removal required sonication in the presence of 1 M CaCl2. Upon further fractionation of the thylakoids into photosystem (PS) I and PSII by lauryl dimethylamine N-oxide solubilization, cyt c550 was exclusively concentrated in the crude PSII fraction together with cyt f, with no significant amount being detected in any of the soluble and PSI fractions. Upon further fractionation of the crude PSII by n-dodecyl beta-D-maltoside solubilization followed by column chromatography, cyt c550 was detected exclusively in the purified PSII core complex fraction but not in any other fractions. A 12-kDa protein, one of the extrinsic components of cyanobacterial PSII, exhibited completely the same behavior as that of cyt c550 during these fractionation procedures. These results, coupled with our previous results that cyt c550 binds stoichiometrically to the cyanobacterial PSII core complex and enhances O2 evolution (Shen, J.-R., and Inoue, Y. (1993) Biochemistry 32, 1825-1832), indicate that there is only one species of cyt c550 in cyanobacterial cells and that this cyt is exclusively associated with PSII as a functional component for O2 evolution.
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PMID:Cellular localization of cytochrome c550. Its specific association with cyanobacterial photosystem II. 839 5

Purified recombinant poly(hydroxyalkanoic acid) (PHA) synthase from Chromatium vinosum (PhaECCv) was used to examine in vitro the specific synthase activity, turnover of R-(-)-3-hydroxybutyryl coenzyme A (3HB-CoA) and poly(3-hydroxybutyric acid) formation under various conditions. The 3HB-CoA consumption was terminated by a reaction-dependent inactivation of the PHA synthase. Salts (MgCl2, CaCl2, NaCl), proteins (bovine serum albumin, lysozyme, phasine) or detergent (Tween 20) increased the 3HB-CoA turnover to 2.5-fold. Specific PHA synthase activity was only partially affected by the added components. In general, a higher concentration of salt often inhibited the activity of PhaECCv without affecting the yield according to 3HB-CoA turnover. NAD+ and NADP+ (2 mM) inhibited PhaECCv completely, whereas NADH and NADPH did not. Macroscopic poly(3HB) granules were formed in vitro if PhaECCv was incubated in the presence of sufficient amounts of 3HB-CoA and if MgCl2 was present. The form and size of the granules synthesized in vitro were affected by the concentration of the PHA synthase protein as well as by bovine serum albumin and the GA24 protein, a poly(3HB)-granule-associated protein of Alcaligenes eutrophus. Scanning electron micrographs from the synthesized granules were obtained. The granules consisted of poly(3HB) that had a molar mass in the range (1-2) x 10(6) g/mol.
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PMID:In vitro biosynthesis of poly(3-hydroxybutyric acid) by using purified poly(hydroxyalkanoic acid) synthase of Chromatium vinosum. 958 Dec 89

During the process of evolution, ancestral lysozymes evolved into calcium-binding lysozymes by acquiring three critical aspartate residues at positions 86, 91 and 92. To investigate the process of the acquisition of calcium-binding ability, two of the aspartates were partially introduced into human lysozyme at positions 86, 91 and 92. These mutants (HLQ86D, HLA92D and HLQ86D/D91Q/A92D), having two critical aspartates in calcium-binding sites, were expressed in Escherichia coli as non-active inclusion bodies. For the preparation of lysozyme samples, a refolding system using thioredoxin was established. This system allowed for effective refolding of wild-type and mutant lysozymes, and 100% of activity was recovered within 4 days. The calcium ion dependence of the melting temperature (Tm) of wild-type and mutant lysozymes was investigated by differential scanning calorimetry at pH 4.5. The Tm values of wild-type, HLQ86D and HLA92D mutants were not dependent on calcium ion concentration. However, the Tm of HLQ86D/D91Q/A92D was 4 degrees higher in the presence of 50 mM CaCl2 than in its absence, and the calcium-binding constant of this mutant was estimated to be 2.25(+/-0.25)x10(2) M(-1) at pH 4.5. Moreover, the calcium-binding ability of this mutant was confirmed by the result using Sephadex G-25 gel chromatography. These results indicate that it is indispensable to have at least two aspartates at positions 86 and 92 for acquisition of calcium-binding ability. The process of the acquisition of calcium-binding site during evolution of calcium-binding lysozyme is discussed.
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PMID:Calorimetric study of mutant human lysozymes with partially introduced Ca2+ binding sites and its efficient refolding system from inclusion bodies. 974 21

Compounds capable of inhibiting protein aggregation may find pharmacological applications in the treatment of a number of diseases called protein condensation diseases [Benedek (1997)], which include cataract, biliary and urinary lithiasis and certain rheumatic diseases. We examined the effect of selected compounds on heat-induced aggregation human serum albumin (HSA), IgG and lysozyme. HSA (0.2% w/v in 0.066 M sodium phosphate pH 5.3 at 22 degrees C), IgG (0.5% w/v in 0.066 M Tris pH 8.0 at 22 degrees C), and L (0.2 % w/v in 0.066 M CAPS pH 11.0 at 22 degrees C) were heated for 30 min at 70 degrees C in the presence or absence of different concentrations of the substance under examination and heat-induced aggregation of 100 microl aliquots was evaluated by measuring the absorbance at 595 nm using an automatic microplate reader. In these conditions, inhibition of aggregation could be due to an anti-denaturant effect or to interferences with the aggregation of denatured molecules, as previously described [Saso, Casini et al. (1998)]. However, this distinction may not be pharmacologically relevant when the target of the therapy is the prevention of abnormal phenomena of protein aggregation. Inorganic salts like NaCl and CaCl2 were active on the three proteins (IgG > HSA > L) but many ligands of HSA such as tryptophan, N-acetyl-tryptophan, caprylic acid, capric acid, cholic acid, deoxycholic acid, chenodeoxycholic acid, lithocholic acid and bendazac were active on their carrier but not on IgG and L, indicating that the latter proteins are more difficult to protect and that specific anti-denaturant and/or anti-aggregant compounds should be developed.
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PMID:Effect of selected substances on heat-induced aggregation of albumin, IgG and lysozyme. 992 Mar 43


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