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

---

Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An efficient yeast promoter was isolated using a beta-galactosidase (beta Gal) promoter probe vector. This promoter was then used to express chicken egg white lysozyme in yeast using a complete intron-free lysozyme-coding sequence constructed by in vitro recombination between a cDNA clone lacking the 5' end and the corresponding 5' end from a nuclear DNA clone. The resulting lysozyme is efficiently exported into the growth medium suggesting that the chicken signal sequence is recognized by the yeast secretion process.
...
PMID:Expression of chicken egg white lysozyme by Saccharomyces cerevisiae. 300 28

Structural studies were carried out on two kinds of teichuronic acid-glycopeptide complexes (designated as TU-GP-I and TU-GP-II) isolated from lysozyme digest of N-acetylated cell walls of Bacillus megaterium AHU 1375 by ion-exchange chromatography and gel chromatography. TU-GP-I, accounting for about 25% of the cell walls, contained N-acetylmannosaminuronic acid, N-acetylglucosamine, glucose, galactose, glycerol, and phosphorus in an approximate molar ratio of 1:1:2:1:0.5:0.5, together with small amounts of glycopeptide components. TU-GP-II, accounting for about 9% of the cell walls, contained glucuronic acid, glucose, and fucose in a molar ratio of about 2:1.5:1, together with small amounts of glycopeptide components. The results of analyses involving Smith degradation, chromium oxidation, methylation, acetolysis, and H-NMR measurement led to the conclusion that the polysaccharide chain of TU-GP-I comprised repeating units,----6) Glc(alpha 1----3)-ManNAcUA(beta 1----4)[Gal(alpha 1----3)][Glc(beta 1----6)]GlcNAc(beta 1----. About half of the repeating units were substituted by glycerophosphoryl residues at C-6 of the beta-glucosyl residues linked to the N-acetylglucosamine residues. By means of a similar procedure, the polysaccharide chain of TU-GP-II was shown to comprise repeating units,----4)GlcUA(alpha 1----3)GlcUA(alpha 1----3)Glc(alpha 1----3)Fuc(alpha 1----, of which about half were substituted by alpha-glucosyl residues at C-3 of the 4-substituted glucuronosyl residues.
...
PMID:Structural studies on N-acetylmannosaminuronic acid-containing and glucuronic acid-containing teichuronic acids in the cell wall of Bacillus megaterium AHU 1375. 308 95

The structure of polysaccharide prepared by lysozyme digestion from the cell wall of Propionibacterium acnes strain C7 was examined. The polysaccharide fraction was composed of glucose, galactose, mannose, galactosamine, and diaminomannuronic acid in a molar ratio of 1:1:0.3:1:2. By Smith degradation of the polysaccharide, diaminouronic acid-containing fractions were obtained, and the configuration of diaminouronic acid was identified as 2,3-diacetamido-2,3-dideoxymannuronic acid [Man(NAc)2A] by means of 1H-NMR and 13C-NMR spectroscopic analyses. The results of analyses involving methylation and partial acid hydrolysis led to the conclusion that the polysaccharide has the repeating unit----6)Gal(alpha 1----4)Man(NAc)2A(beta 1----6)Glc(alpha 1----4)Man(NAc)2A (beta 1----3)GalNAc(beta 1--. In addition, a portion of the galactose residues were substituted at C-4 by alpha 1----2 linked mannotriose.
...
PMID:Structure of acidic polysaccharide from cell wall of Propionibacterium acnes strain C7. 403 Jul 44

The action of purified N-acetylmuramoylhydrolase (muramidase, EC 3.2.1.17) of Streptococcus faecium ATCC 9790 on linear, uncross-linked, soluble, peptidoglycan chains produced by the same organism in the presence of benzylpenicillin was characterized as a processive exodisaccharidase. Specific labels, one [( 14C]Gal) added to the nonreducing ends of chains, and the other (3H from [3H]NaBH4) incorporated into the reducing ends of the chains, were used to establish that an enzyme molecule binds at the nonreducing terminus and sequentially hydrolyzes the glycosidic bonds, releasing disaccharide-peptide units. An enzyme molecule remains bond to a chain, and is not released at a detectable rate, until hydrolysis of that chain is complete. Reaction rates increased with the length of the polymer chain to give a maximum of 91 bonds cleaved/min/enzyme molecule for hydrolysis of a continuous polymeric substrate. The relationship between hydrolytic rate and glycan chain length is consistent with hydrolysis of bonds within the chain followed by slow release of enzyme from the distal, reducing terminus. This mechanism was experimentally confirmed by analysis of product formation during hydrolysis with stoichiometric mixtures of enzyme and soluble peptidoglycan chains. Kinetic analyses showed an apparent Km of 0.17 microM for the enzyme, independent of substrate polymer length. The dissociation constant for the initial enzyme-substrate complex was calculated to be 1.5 nM. Kinetic analyses are consistent with one catalytic site per enzyme molecule. The Kcat/Km value of 9 X 10(6) M-1 S-1 is near the limit imposed by diffusion for the initial hydrolytic events when long chains are hydrolyzed. The kinetic and physical properties of this muramidase are highly consistent with its location outside of the cellular permeability barrier and its ability to remain with and hydrolyze appropriate bonds in the cell wall in such an environment.
...
PMID:The mechanism of soluble peptidoglycan hydrolysis by an autolytic muramidase. A processive exodisaccharidase. 648 May 85

The binding of the disaccharides methyl beta-D-lactoside and 2-acetamido-2-deoxy-3-O-(beta-D-galactopyranosyl)-beta-D-galactopyranose [beta-D-Gal-(l leads to 3)-D-GalNAc] to peanut agglutinin was studied by ultraviolet difference spectroscopy. The magnitude of the difference spectra varied with the concentration of the carbohydrates; association constants and thermodynamic parameters were determined from titration experiments at different temperatures. The enthalpy and entropy changes for binding of methyl beta-D-lactoside were found to be delta H degree = -65 +/- 4 kJ mol-1, delta S degree = -156 +/- 14 J mol-1 K-1. For beta-D-Gal-(1 leads to 3)-D-GalNAc the observed thermodynamic parameters were delta H degree = -78 +/- 5 kJ mol-1, delta S degree = -177 +/- 16 J mol-1 K-1. For both disaccharides, the enthalpy change upon binding to the lectin is much larger than found for the binding site on peanut agglutinin. The observed parameters are compared with those found for the binding of monosaccharides and oligosaccharides to other lectins and to lysozyme. Molecular models of the minimum energy conformers of beta-D-Gal(1 leads to 3)-D-GalNAc and methyl beta-D-lactoside are used to interpret the interaction of these, and structurally related ligands, with the peanut agglutinin binding site.
...
PMID:A sphingomyelin transfer protein in rat tumors and fetal liver. 680 33

The binding of the disaccharides methyl beta-D-lactoside and 2-acetamido-2-deoxy-3-O-(beta-D-galactopyranosyl)-beta-D-galactopyranose [beta-D-Gal-(l leads to 3)-D-GalNAc] to peanut agglutinin was studied by ultraviolet difference spectroscopy. The magnitude of the difference spectra varied with the concentration of the carbohydrates; association constants and thermodynamic parameters were determined from titration experiments at different temperatures. The enthalpy and entropy changes for binding of methyl beta-D-lactoside were found to be delta H degree = -65 +/- 4 kJ mol-1, delta S degree = -156 +/- 14 J mol-1 K-1. For beta-D-Gal-(1 leads to 3)-D-GalNAc the observed thermodynamic parameters were delta H degree = -78 +/- 5 kJ mol-1,, delta S degree = -177 +/- 16 J mol-1 K-1. For both disaccharides, the enthalpy change upon binding to the lectin is much larger than found for the binding site on peanut agglutinin. The observed parameters are compared with those found for the binding of monosaccharides and oligosaccharides to other lectins and to lysozyme. Molecular models of the minimum energy conformers of beta-D-Gal(1 leads to 3)-D-GalNAc and methyl beta-D-lactoside are used to interpret the interaction of these, and structurally related ligands, with the peanut agglutinin binding site.
...
PMID:Binding of disaccharides by peanut agglutinin as studied by ultraviolet difference spectroscopy. 707 91

We examined the specificity of glycopeptide-specific CD4 T cells following procedures similar to those previously reported by us. The disaccharide galabiose (Gal alpha 1-4Gal) was attached to the middle of the 52-61 peptide of hen egg lysozyme. This peptide is well known to bind to I-Ak molecules. CBA/J mice were immunized and T cell hybridomas were derived from the popliteal lymph node T cells. For this study, we selected hybridomas that recognized galabiose conjugated to 52-61 at residue Ser 56. We demonstrate here that these hybridomas showed specificity for galabiose and not cellobiose (Glc beta 1-4Glc). Peptides containing galabiose at residue 53 did not stimulate the T cell hybridomas and neither did galabiose conjugated to the 34-45 peptide of HEL. Acetylation of the hydroxyl groups of the disaccharide resulted in loss of T cell reactivity. These results need to be contrasted with those in which the T cells were directed to galabiose, attached to the amino terminus of 52-61 or to Ser at residue 53. With these results, the fine specificity of recognition of the disaccharide was not apparent. Our results indicate two sets of glycopeptide-specific T cells. One is probably induced by a conformational change induced by the disaccharide on the peptide bound to class II MHC molecules. The second set contains elements of specificity for both the disaccharide and the peptide.
...
PMID:Specificity of glycopeptide-specific T cells. 763 81

Hepatic targeting of proteins utilizing the sugar-recognition mechanism was investigated in mice after intravenous injection. Five proteins with different molecular weights, i.e., bovine gamma-globulins (IgG), bovine serum albumin (BSA), recombinant human superoxide dismutase (SOD), soybean trypsin inhibitor (STI), and chicken egg white lysozyme (LZM), were modified with 2-imino-2-methoxyethyl 1-thiogalactoside to obtain galactosylated proteins (Gal-IgG, Gal-BSA, Gal-SOD, Gal-STI, and Gal-LZM). The numbers of galactose residues were 38, 20, 11, 6, and 5 for Gal-IgG, Gal-BSA, Gal-SOD, Gal-STI, and Gal-LZM, respectively. All galactosylated proteins were dose-dependently taken up by the liver and the relative amount accumulated in the liver was decreased with an increase of the administered dose. At low doses (0.05 and 0.1 mg/kg), Gal-IgG, Gal-BSA, and Gal-SOD could be taken up by the liver up to more than 70-80% of dose within 10 min after intravenous injection, but the maximum amounts accumulated in the liver were approximately 40 and 30% of the dose for Gal-STI and Gal-LZM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Design for cell-specific targeting of proteins utilizing sugar-recognition mechanism: effect of molecular weight of proteins on targeting efficiency. 778 35

When attempting to generate mouse monoclonal antibodies to hen's egg ovalbumin, injection of commercially purified ovalbumin resulted in monoclonal antibodies, which when assayed against commercially purified ovalbumin (Gal d I) or ovomucoid (Gal d III), appeared to be specific to both. With the use of high-performance liquid chromatography (HPLC)-repurified ovalbumin and ovomucoid in assay procedures, monoclonal antibodies generated by commercially purified ovalbumin were found to be specific for ovomucoid only. To clarify this phenomenon, mice were serially injected with commercially purified ovalbumin or HPLC-repurified ovalbumin. It was found that most of the antibody response to commercially purified ovalbumin was directed against the minor (< 1%) ovomucoid contaminant and that HPLC-repurified ovalbumin failed to produce antibodies to ovomucoid. Commercially purified ovomucoid resulted in only minimal amounts of antibodies to ovalbumin. Thus when commercially purified ovalbumin is used both for immunization and immunoassay, most of the antibodies produced are actually against the small amount of ovomucoid contaminant, and not ovalbumin. To determine whether ovomucoid is the major antigenic and allergenic egg white protein in human beings, one group of 18 children with egg allergy were skin prick tested with half-log dilutions of egg white extract and diethylaminoethyl cellulose (DEAE)-repurified ovomucoid, ovalbumin, and lysozyme. Ovomucoid mean wheal diameters were significantly greater than wheal diameters in response to ovalbumin, lysozyme, and egg white extract at the three most concentrated of five dilutions tested: 0.01, 0.03, and 0.1 mg/ml (p < 0.01). Serum ovomucoid-specific IgE and IgG antibody concentrations to DEAE-repurified ovomucoid were significantly greater than that to DEAE-repurified ovalbumin (p < 0.05). In a second study, 10 patients with egg allergy and persistent egg hypersensitivity were compared with 11 patients with egg allergy in whom clinical tolerance to egg developed. IgE antibodies to repurified ovomucoid were significantly greater in patients with persistent egg hypersensitivity compared with patients in whom clinical tolerance developed at the time of both initial and follow-up food challenges. In contrast, there were no significant differences in IgE antibody concentrations to repurified ovalbumin in either group at any time. These results suggest that ovomucoid is the immunodominant protein fraction in egg white and that the use of commercially purified ovalbumin has led to an overestimation of the dominance of ovalbumin as a major egg allergen and antigen in human beings.
...
PMID:Allergenicity and antigenicity of chicken egg ovomucoid (Gal d III) compared with ovalbumin (Gal d I) in children with egg allergy and in mice. 800 9

We have developed an efficient positive-selection vector to insert foreign DNA segments fused to the T4 ipIII gene (encoding internal protein IPIII) into the bacteriophage T4 genome. By using partial deletions of the T4 e gene, which encodes phage lysozyme, lysozyme activity required for plaque formation is used to select plasmid integrants which restore the e gene. In this work, we demonstrate that DNA inserts more than 7.0 kb in length can be incorporated into a T4 genome lacking the alt gene. In addition, the recombinant T4 not only contains a fusion gene driven by the T4 ipIII promoters, but also packages the fusion protein into the T4 capsid due to targeting by the IPIII portion. This expression-packaging-processing system shows that active IPIII::beta Gal fusion reporter protein is produced and packaged during phage infection.
...
PMID:An expression-packaging-processing vector which selects and maintains 7-kb DNA inserts in the blue T4 phage genome. 829 2


1 2 3 4 Next >>

---