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 antimicrobial peptides were extracted from the cytoplasmic granules of rabbit neutrophils with 0.01 mol/L citric acid. SDS-PAGE gel densitometric analysis of the citric acid extract showed that they accounted for 34%-42% of the total extract proteins. When subjected to acid urea polyacrylamide gel electrophoresis, five peptides migrated much further to the cathode than lysozyme. Beginning with the most cathodal component, they were in turn referred to as NP1, NP2, NP3, NP4, and NP5. They were purified from the citric acid extract by virtue of preparative polyacrylamide gel electrophoresis. Each of them was of low molecular weight (2,500-6,000) as determined by SDS-PAGE. Three of the peptides were tested in vitro for fungicidal activity. When Candida albicans (10(7)/ml) were incubated with 12.5 micrograms/ml of NP1 or NP2 at 37 degrees C for 2 h, the death rates of the organisms were 96.6% and 93.3% respectively. NP3 was shown to be active against Candida albicans although less potent than NP1 and NP2.
Hua Xi Yi Ke Da Xue Xue Bao 1990 Mar
PMID:[Purification and identification of antimicrobial peptides of rabbit neutrophils]. 219 31

Acid-soluble extract of human bladder mucosal surface was obtained by washing out the bladder of accidentally dead male human with 1% acetic acid in the presence of proteinase inhibitors. Acid urea polyacrylamide gel electrophoresis (AU-PAGE) indicated that the acid-soluble extract had more than 10 main protein bands, but the currently known antibiotic peptides, e. g., Lysozyme and defensins, were not found in this extract. The quantitation assay of lysozyme showed that lysozyme only amounted to 2.2 microgram per milligram protein. When tested for antibacterial activity by using ultrasensitive radial diffusion assay, the acid-soluble extract effectively killed E. coli ML-35P. The antibacterial activity of the acid-soluble extract was further analysed by gel overlay technique and the result showed that one main protein band, which was referred to as human bladder protein (HBP), was potently antibacterial against E. coli ML-35P. The HBP accounted for 4% of the total acid-soluble extract protein. These results suggest that the presence of antibacterial protein in the bladder mucosa may be the molecular base of the bladder antibacterial defence mechanisms.
Hua Xi Yi Ke Da Xue Xue Bao 1994 Jun
PMID:[Study on antibacterial protein from human urinary bladder mucosa]. 780 84

Acid-soluble extract of rabbit bladder mucosa was obtained by washing out the bladder of normal female New Zealand rabbit with 1% acetic acid in the presence of proteinase inhibitors. Acid urea polyacrylamide electrophoresis (AU-PAGE) analysis indicated that the extract had more than 10 main protein bands. The currently-known antibiotic peptides, e. g. lysozyme and defensin-like molecules were not found in this material. When tested for antibacterial activity by using ultrasensitive radial diffusion assay, the acid-soluble extract effectively killed E. coli ML-35P. The gel overlay assay showed that the anti-bacterial activity of the acid-soluble extract was relevant to two protein bands referred to as rabbit bladder protein 1 (Rab BP-1) and rabbit bladder protein 2 (Rab BP-2). The Rab BP-1 and Rab BP-2 accounted for 2.5% and 1.2% of the total acid-soluble extract proteins, respectively. These results suggest that the long recognized ability of the normal rabbit bladder wall to kill adherent E. coli may result from the presence of endogenous antibacterial proteins associated with its mucosa.
Hua Xi Yi Ke Da Xue Xue Bao 1993 Dec
PMID:[Study on antibacterial proteins from rabbit bladder mucosa]. 815 Apr 30

The acid-soluble extract of rat uterus cavity wall was obtained by washing out the normal Sprague-Dawley rat uterus cavity with 1% acetic acid in the presence of protease inhibitors. When tested for antibacterial activity by sensitive agarose diffusion assay, the extract effectively killed E. coli ML-35P. The bactericidal activity of the acid-soluble extract was further analyzed by gel overlay technique. The result showed that three protein bands, which were designated rat uterus protein 1 (rat UP-1), rat uterus protein 2 (rat UP-2), and rat uterus protein 3 (rat UP-3), were potently antibacterial against E. coli ML-35P. The rat UP-1, rat UP-2, and rat UP-3 accounted for 4.5%, 5.7%, and 6.6% of the total proteins of the rat uterus acid-soluble extract respectively. The lysoplate assay for the determination of lysozyme activity showed that extract had some lysozyme activity, but the activity was very low. AU-PAGE analysis of the extract did not show the presence of lysozyme on the gel. This study suggested that the uterus wall might secrete some currently-unknown antibiotic polypeptides which play an important role in the uterus defense against bacterial infections.
Hua Xi Yi Ke Da Xue Xue Bao 1995 Sep
PMID:[Antibacterial components of rat uterus]. 858 88

The effect of guanidinium chloride (GdmCl) on the renaturation of denatured-reduced chicken egg white lysozyme was studied. It was found that the renaturation yield was significantly related to the GdmCl concentration, that is, the GdmCl concentration required to obtain a high renaturation yield increased with the increase of the denatured lysozyme concentration. When denatured lysozyme concentrations were lower than 0.21 g/L, the presence of 0.7 mol/L GdmCl resulted in the complete renaturation of lysozyme, while higher GdmCl concentration, i.e., 1.0--1.5 mol/L, was needed to yield more than 95% renaturation of 0.6--1.05 g/L of the denatured lysozyme. In addition, lysozyme renaturation rate decreased with increasing GdmCl concentration. Therefore, it is considered that optimizing GdmCl concentration is the key step to enhance the renaturation yield of denatured proteins.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 2001
PMID:Effect of Guanidinium Chloride Concentration on the Renaturation of Denatured Lysozyme. 1204 Apr 21

In order to efficiently recover recombinant proteins, a temperature-sensitive lytic system was constructed on the basis of the feature that T4 lysozyme disrupts the bacteria through cutting specific bond in the peptidoglycan layer of cell wall. This system was evaluated by constructing and introducing a low copy plasmid pSC-lys (pSC101 replication origin) into E.coli. The plasmid contained a temperature sensitive T4 lysozyme (LYS(ts)) gene under the control of three tandem tac promoters and the LacI repressor, which is compatible with other plasmids carrying pMB1, ColE1 replication origins, etc. Under the optimum lysis conditions, 2--5 fold condensed cultures resuspended in buffer A, beta-galactosidase, recombinant chaperone GroEL and ZZ-fusion salmon hexamic calcitonin (Cal6) in E.coli were released simply, rapidly, and quantitatively, as co-expressed with LYS(ts). The two tested recombinant proteins maintained their significant productions. Instead of other cumbersome lysising methods, this novel lytic system will be useful in recovery of recombinant proteins for further purification in the field of biotechnology.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 2000
PMID:The Application of a Novel Lytic System to the Recovery of Recombinant Proteins in E.coli. 1207 42

A 1ysozyme from Raphanus sativus leaves was purified by the method of affinity chromatography on a deaminated regenerated crab chitin column. The purified enzyme was crystallized and showed a single band on polyacrylamide gel disc electrophoresis. The functional groups at the active center of the enzyme were studied by the method of pH dynamics and chemical modification. It was found that carboxyl groups(Glu/Asp), tryptophanyl and histidyl residues were probably essential groups for the catalytic activity. The enzymatic activity was not affected when the enzyme was modified by reagents which could specifically react with tyrosyl, cysteinyl, arginyl and seryl/threonyl residues. It was inhibited by histamine and GlcNAc. The difference among Raphanus sativus lysozyme, HEWI and papaya lysozyme was discussed.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 1997
PMID:Preliminary Studies on the Amino-acid Residues at Active Center of the Lysozyme from Raphanus sativus Leaves. 1221 3

The folding transition thermodynamics parameters and activity of hen egg white lysozyme and its mutants, R21E, A31V, I55L, S91A, D101A, SIS, TIT, SVS, TVS by site-directed mutagenesis in urea solutions of various concentration were measured. The values of free energy of stabilization (delta G(T)(H(2)O)) are 16.87-28.67 kJ/mol at 25 degrees, and those at midpoint of urea concentration for folding transition [C](1/2) are 4.89-6.24 M for the mutants, respectively. The possible folding transition mechanism in urea solution, the change of transition thermodynamic stability induced by site-directed mutagenesis, and the contribution of hydrophobic interaction and the volume change of amino acid residues to protein stability were discussed.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 1997
PMID:Thermodynamic Stability of Hen Egg White Lysozyme and Its Mutants by Site-directed Mutagenesis. 1221 14

In a previous study, we explored the mechanism of urea-induced denaturation of proteins by performing molecular dynamics (MD) simulations of hen lysozyme in 8 M urea and supported the "direct interaction mechanism" whereby urea denatures protein via dispersion interaction (Hua, L.; Zhou, R. H.; Thirumalai, D.; Berne, B. J. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 16928). Here we perform large scale MD simulations of five representative protein/peptide systems in aqueous urea to investigate if the above mechanism is common to other proteins. In all cases, accumulations of urea around proteins/peptide are observed, suggesting that urea denatures proteins by directly attacking protein backbones and side chains rather than indirectly disrupting water structure as a "water breaker". Consistent with our previous case study of lysozyme, the current energetic analyses with five protein/peptide systems reveal that urea's preferential binding to proteins mainly comes from urea's stronger dispersion interactions with proteins than with bulk solution, whereas the electrostatic (hydrogen-bonded) interactions only play a relatively minor (even negative) role during this denaturation process. Furthermore, the simulations of the peptide system at different urea concentrations (8 and 4.5 M), and with different force fields (CHARMM and OPLSAA) suggest that the above mechanism is robust, independent of the urea concentration and force field used. Last, we emphasize the importance of periodic boundary conditions in pairwise energetic analyses. This article provides a comprehensive study on the physical mechanism of urea-induced protein denaturation and suggests that the "dispersion-interaction-driven" mechanism should be general.
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PMID:Coherent microscopic picture for urea-induced denaturation of proteins. 2278 Mar 26