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)

Thin sections of the cell wall of Sporosarcina ureae revealed two structurally distinct layers: a continuous amorphous zone, approximately 15 nm thick, which was adjacent to the plasma membrane, and an overlying periodic zone, approximately 16 nm thick. Sequential Triton X-100 and lysozyme treatment of isolated walls produced small fragments of the outer regular structure which allowed high-resolution, negatively stained images suitable for optical diffractometric analysis. These data suggested a tetragonal array of complex polygonal units of C-C spacing = 12 nm, with each unit joined to another by two delicate linkers. The array was entirely proteinaceous, consisting of a 150,000-dalton polypeptide which had a high affinity for Mg2+. It proved to be sensitive to chelating agents, 5 mM concentrations of Ca2+, Sr2+, or Ba2+, proteases, heat greater than or equal to 45 degrees C, sodium dodecyl sulfate, and pH greater than or equal to 5.8, but magnesium offered protection against the chelating agents and the deleterious salts.
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PMID:Surface arrays on the wall of Sporosarcina ureae. 47 3

Though DNase does not contain any cysteine residues, incubation of the enzyme with 2-nitro-5-thiocyanobenzoic acid in the presence of Ca2+ at pH values above 7.5 results in an irreversible inactivation of the enzyme. The inactivation also occurs when Ca2+ is replaced by Mg2+, but not in their absence. Amino acid analyses after acid hydrolyses of the completely inactivated ant the native enzymes show no significant differences in composition, including tryptophan and half-cystine residues. However, sodium dodecyl sulfate gel electrophoresis indicates enzyme cleavage by the treatment with 2-nitro-5-thiocyanobenzoic acid. This reagent does not inactivate chymotrypsin and lysozyme, and under conditions where bovine DNase is inactivated, does not inactivate other nucleases such as ribonuclease, snake venom phosphodiesterase, and spleen acid DNase. However, it inactivates malt DNase and can, therefore, be considered a specific inhibitor of DNase I. The inactivation kinetics is pseudo-first order, resembling Michaelis-Menten, with an affinity constant of 16.7 mM. It is the cyano group, not the thionitrobenzoic acid of 2-nitro-5-thiocyanobenzoic acid that reacts to form cyano-DNase.
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PMID:Inactivation of bovine pancreatic DNase by 2-nitro-5-thiocyanobenzoic acid. I. A novel inhibitor for DNase I. 48 54

Triclinic crystals of hen egg-white lysozyme cross-linked with glutaraldehyde have been treated with various denaturants and found to be susceptible to x-ray structure analysis even after major conformational changes in the protein. Cross-linked crystals were isomorphous with the native form, and electron density difference maps indicated the locations of intermolecular corss-links, but showed no appreciable differences in the protein conformation. Soaking of the cross-linked crystals in danaturant solutions of increasing concentrations caused corresponding increases in crystal volume and decreases in minimum observable x-ray spacings. These changes proved partly reversible on diluting the solutions, and measurements of crystal volume and minimums x-ray spacing were used to follow denaturation and renaturation as a function of concentration for several denaturants. Some of these, including bromoethanol and sodium dodecyl sulfate, had little effect on the crystals below critical concentrations at which there was a sharp volume increase and loss of x-ray pattern, which could, however, be regenerated to about 3.2-A resolution. Others, including KCNS and urea, caused more gradual changes, but with a smaller degree of recovery. It is suggested that at least two different denaturation mechanisms are involved with detergent-like reagents disrupting the hydrophobic interactions joining the two wings of the lysozyme molecule and hydrophilic denaturants interacting primarily with polar groups on the molecular surface.
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PMID:Crystallographic studies of protein denaturation and renaturation. 1. Effects of denaturants on volume and X-ray pattern of cross-linked triclinic lysozyme crystals. 55 40

Bovine and human tendon tissue do not induce calcification in vitro. However, extraction of those tissues with 3% Na2HPO4 converts them to calcifiable matrices. The supernatant fraction derived from the extraction contains a nondialyzable, perchloric acid soluble component that inhibits calcification of the extracted matrix. This inhibitory substance is characterized by a molecular weight in the range of 85,000-100,000. Exposure to pronase or hyaluronidase did not alter the inhibitory potency but did render the inhibitor dialyzable. Commercial sources of hyaluronic acid, chondrotitin-6-sulfate, chrondroitin-4-sulfate, dermatan sulfate, heparin and lysozyme did not inhibit calcification of the extracted matrix. Phosvitin, a phosphoglycoprotein is a potent inhibitor. Although phosvitin and the tendon extract also inhibit calcification of previously calcified matrix, they have no detectable effect on the rate of decalcification. We conclude that the mechanism of inhibition is characterized by a degree of specificity and that phosvitin and a macromolecular component of tendon tissue blocks conversion of an intermediate matrix-bound CaP complex to crystalline apatite. It seems reasonable that the tendon inhibitor could function in situ and possibly in vivo to control calcification of tendon tissue.
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PMID:A macromolecular inhibitor of in vitro calcification of tendon matrix. 66 63

For the isolation of human lysozyme from the urine of leukemia patients, a simple method has been established which involves precipitation of urinary proteins by 60% saturation with ammonium sulfate, fractionation of crude lysozyme on Sephadex G-50 and purification by CM-Sepharose chromatography. By this method approximately 60% of the lysozyme in the urine was isolated in a pure state in ten days.
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PMID:Isolation of human urinary lysozyme. 71 8

Pig epiphyseal cartilage (proximal ulna epiphysis) previously incubated into vitro in the presence of sodium [35S]sulfate or [3H]thymidine was either analyzed by autoradiography or separated into 9 morphologically defined consecutive layers and investigated for 35S-incorporation into the guanidinium chloride-extractable proteoglycans and for lysozyme activity. The lowest 35S incorporation and lysozyme activity were determined in the zone of resting cells, but there is a consecutive increase in the rate of proteoglycan synthesis and lysozyme activity toward the diaphyseal cartilage-bone junction, with the maximum at the lower columnar cell zone and a sharp reduction of both parameters at the hypertrophic zone. The maxima of 35S incorporation and [3H]thymidine incorporation do not coincide. The guanidinium chloride-soluble proteoglycans exhibit macromolecular polydispersity. Fractions excluded from as well as retarded by Sepharose 2B gel could be separated and were detected in all zones. The results indicate a correlation of proteoglycan biosynthesis and lysozyme activity in epiphyseal cartilage.
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PMID:Correlation of lysozyme activity with proteoglycan biosynthesis in epiphyseal cartilage. 73 63

Very fast-sedimenting DNA was isolated from cells after infection with gene 49 defective phage T4. This DNA appeared membrane bound throughout the time after infection and could be isolated either in the membrane-bound form (M-DNA) or free of membrane (released DNA) depending on the lysis procedure. Released DNA formed complexes of marked stability with sedimentation velocities between 1,400S and 2,100S. These complexes did not seem to contain material other than DNA. This was concluded from the results of RNA, protein, and membrane labeling experiments and density analysis. In addition, these complexes were resistant against treatment with n-butanol, phenol. chloroform-methanol, sodium dodecyl sulfate, Sarkosyl, Pronase, RNase, or lysozyme. The observation that more then 90% of the purified very fast-sedimenting DNA is retrapped by magnesium-Sarkosyl crystals (M-band) suggests that the M-band technique may not be sufficient as a test for DNA-membrane attachment.
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PMID:Function of gene 49 of bacteriophage T4. I. Isolation and biochemical characterization of very fast-sedimenting DNA. 77 32

Hydrolysis of the cell wall of Bacillus subtilis 168 by autolysins or lysozyme resulted in the exposure of glucosylated teichoic acid molecules as evidenced by increased precipitation of [14C] concanavalin A. The number of concanavalin A-reactive sites increased significantly after only limited enzymatic digestion of the walls. Quantitative analyses of [14C] concanavalin A-treated wall or wall hydrolysate complexes indicate that approximately one-half of the teichoic acid molecules are surface-exposed, whereas the remainder are probably embedded within the peptidoglycan matrix. Treatment of the cell walls with sodium dodecyl sulfate or Triton X-100 did not result in new concanavalin A-reactive sites. Partial autolysis diminished the ability of the cell walls to adsorb bacteriophage phi25. Fluorescein-labeled concanavalin A bound intensely over the entire surface of growing B. subtilis 168 cells, suggesting that teichoic acid molecules are located on the total solvent-exposed surface area of the bacteria.
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PMID:Distribution of teichoic acid in the cell wall of Bacillus subtilis. 80 66

The protoplasts of a mutant of Bacillus subtilis 168 (B. subtilis CMK33) are osmotically fragile when compared to protoplasts of the parent organism and contain an active, membrane-associated phospholipase A1. A protein found in the parent organism specifically inhibits the phospholipase A1 (Kent, C., and Lennarz, W.J. (1972) Proc. Nat. Acad. Sci. U.S.A. 69, 2793-2797). The inhibitor exists in both a soluble and particulate form. The soluble inhibitor is not found in the cytoplasm, but rather in a "periplasmic" fraction released from the cell during incubation with lysozyme. The soluble inhibitor has been purified to homogeneity by diethylaminoethyl-cellulose and hydroxylapatite chromatography. Its molecular weight is 28,000 to 32,000 as determined by gel filtration chromatography and 36,000 to 37,000 as determined by sodium dodecyl sulfate-urea gel electrophoresis. The inhibitor appears to inactivate the membrane bound phospholipase A1 by an enzymatic process that is dependent on time and protein concentration. Binding of the inhbitor to the membrane-associated phospholipase cannot be detected. When purified inhibitor is added to cells of B. subtilis CMK33 during treatment with lysozyme, the osmotic stability of the resultant protoplasts is similar to that of protoplasts of the wild type of organism.
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PMID:Purification and characterization of an inhibitor of phospholipase A1 in Bacillus subtilis. 80 82

The cell envelope of Neisseria gonorrhoeae, colony type 4, was studied. Outer membrane was isolated by lysozyme and ethylenediaminetetraacetic acid treatment of plasmolyzed cells according to Wolf-Watz et al. (1973). The degree of purity of the membrane preparations was checked by electron microscopy. The membrane fraction obtained had a density of 1.25 g/cm(3), was rich in phospholipase A and lysophospholipase, and contained only 10% of the total membrane activity of succinate dehydrogenase and d-lactate dehydrogenase. The outer membrane protein profile after sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed at least six major proteins. The predominating protein showed a molecular weight of 35,000. The lipopolysaccharide component was characterized by gas chromatography. The carbohydrates found were galactose, glucose, and glucosamine. d-Glycero-l-manno-heptose was present in very low amounts. Lipid A contained lauric acid, stearic acid, and beta-hydroxy-myristic acid. About 20% of the fatty acids in the outer membrane was derived from lipid A. The phospholipids were characterized as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. There was no evidence for a lipoprotein anchored to the peptidoglycan. The peptidoglycan of N. gonorrhoeae was of the chemotype I. The cell envelope of N. gonorrhoeae was found to be highly permeable to gentian violet. Cell envelopes of one penicillin-resistant and two penicillin-sensitive strains were compared. Only moderate differences in fatty acid composition were found.
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PMID:Cell envelope of Neisseria gonorrhoeae: outer membrane and peptidoglycan composition of penicillin-sensitive and-resistant strains. 80 26


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