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)

Spores of Bacillus cereus T treated with trichloroacetic acid (6.1--61.2 mM) were compared with untreated spores, and as the concentration of the chemical increased, the following alterations in spore properties were found: (1) the extent of germination decreased irrespective of the germination medium used; (2) the spores became sensitive to sodium hydroxide (1 N) and hydrochloric acid (0.27 N), but not to lysozyme (200 micrograms/ml); (3) loss of dipicolinate increased on subsequent heating; and (4) the spores became more sensitive to heat. However, trichloroacetic acid-treated spores were still viable and there was no significant change in spore components. The mechanism of action of trichloroacetic acid is discussed.
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PMID:Effect of trichloroacetic acid treatment on certain properties of spores of Bacillus cereus T. 4 Nov 62

A new method has been developed which permits the rapid screening of E. coli colonies for mutants with defective enzymes of phospholipid metabolism. In this procedure, a disc of filter paper is pressed down on an agar plate containing several hundred colonies of mutagen-treated cells, after which the paper is lifted off. In the process the colonies are transferred to the paper, giving rise to a replica print of the master plate. The few cells from each colony left on the master keep growing in the original pattern. The pattern of colonies is also retained on the filter paper, even after the cells are rendered permeable with lysozyme and EDTA. Colonies treated in this manner remain absorbed to the paper, where they can convert sn-(U-14-C)glycero-3-P to phosphatidyl(U-14-C)glycerophosphate, dependent on added CDP-diglyceride. Unrelated reactions of sn-(U-14-C)glycero-3-P that may obscure the synthesis of phosphatidyl-glycerophosphate are inhibited by the addition of reagents poisoning energy generation. The radioactive phospholipid that forms around each colony on the paper is precipitated in situ with trichloroacetic acid, and unreacted sn-(U-14-C)glycero-3-P is washed away. After autoradiography, the colonies on the filter paper are stained with Coomassie blue. When the autoradiogram is superimposed on the strained paper, mutants are identified as blue colonies lacking a black halo. With this method, 20,000 colonies were screened in several days. Four mutants were identified with low levels of CDP-diglyceride:snglycero-3-P phosphatidyl transferase (EC 2.7.8.5, GLYCEROL-PHOSPHATE PHOSPHATIDYLTRANSFERASE, PHOSPHATIDYLGLYCEROPHOSPHATE SYNTHETASE) IN EXTRACTS. With a similar assay, 10,000 additional colonies were screened for mutants with altered CDP-diglyceride:L-serine O-phosphatidyltransferase (EC 2.7.8.8, phosphatidylserine synthetase), and four strains were found in which the enzyme is thermolabile. The screening technique described here is termed replica printing and should be applicable not only to studies of phospholipid metabolism but also to nucleic acid and protein synthesis.
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PMID:Isolation of Escherichia coli mutants defective in enzymes of membrane lipid synthesis. 4 56

Stable and metabolically active protoplasts were prepared from the unicellular cyanophyte, Anacystis nidulans, by enzymatic digestion of the cell wall with 0.1% lysozyme. The yield of protoplasts from intact algal cells was approx. 50%. Incorporation of L-[U-14C]leucine into cold trichloroacetic acid-insoluble material from protoplasts preparations was linear for 1.5 h and continued for an additional 2.5 h. Incorporation of radiolabeled leucine into hot trichloroacetic acid-insoluble material from protoplast preparations demonstrated protein synthesis in protoplasts in vitro. Phycocyanin is the principal phycobiliprotein and allophycocyanin is a minor phycobiliprotein in A. nidulans cells. The light-absorbing chromophore of both of these phycobiliproteins is the linear tetrapyrrole (bile pigment), phycocyanobilin. Radiolabeled phycocyanin and allophycocyanin were isolated from protoplast preparations which had been incubated with L-[U-14]leucine or delta-amino[4-14C] levulinic acid (a precursor of phycocyanobilin). The radio-labeled phycobiliproteins were purified by ammonium sulfate fractionation and ion-exchange chromatography on brushite columns. The specific radioactivity of phycocyanin and allophycocyanin in brushite column eluates (protoplasts incubated with radiolabeled leucine) was 106 000 and 82 000 dpm/mg, respectively. The specific radioactivity of phycocyanin and allophycocyanin in brushite column eluates (protoplasts incubated with radiolabeled delta-aminolevulinic acid) was 33 000 and 38 000 dpm/mg, respectively. Phycobiliproteins from protoplasts incubated with radiolabeled leucine were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 25% of the incorporated radioactivity in protoplast lysates and approx. 60% of the incorporated radioactivity in protoplast lysates and approx. 60% of the incorporated ratioactivity in phycocyanin and allophycocyanin (in brushite column eluates) comigrated with the subunits of these phycobiliproteins on sodium dodecyl sulfate-polyacrylamide gels. Chromic acid degradation of phycobiliproteins from protoplast preparations incubated with delta-amino[4-14C] levulinic acid yielded radiolabeled imides which were derived from the phycocyanobilin chromophore. Imides from radiolabeled phycobiliproteins isolated from protoplast preparations incubated with L-[U-14C]leucine did not contain radioactivity. These results show that both the apoprotein and tetrapyrrolic moieties of phycocyanin and allophycocyanin were synthesized in A. nidulans protoplasts in vitro.
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PMID:Phycobiliprotein synthesis in protoplasts of the unicellular cyanophyte, Anacystis nidulans. 9 57

Peptidoglycan is responsible for the endotoxin-like properties of the streptococcus cell wall. The pyrogenic response of rabbit to group A streptococcus peptidoglycan prepared by hot formamide or TCA is dose-dependent and is increased if the material is ultrasonically solubilized. The pyrogenicity can be eliminated by the antiserum to the peptidoglycan or by the degradation of the material by lysozyme. Peptidoglycans prepared from cell walls of group B and L streptococci, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumoniae produce fever effects comparable to the response after group A streptococcus peptidoglycan. Spirillum serpens and Escherichia coli contain in addition to endotoxin the peptidoglycan which is also pyrogenic. Repeated injections of bacterial peptidoglycan to rabbit result in tolerance to the fever effect. Cross-tolerance was recorded only exceptionally. Rabbits tolerant to endotoxin respond with a lower fever to S. aureus and group A streptococcus peptidoglycans. Intravenous administration of peptidoglycan to rabbit causes extensive alterations in the heart characterized by various stages of the degenerative and necrotic process. Local Shwartzman reaction can be elicited in rabbit by peptidoglycan used either as a preparative or as a provocative dose in combination with endotoxin, or it can be used for both doses. The results obtained with peptidoglycans prepared from various bacteria are fully comparable. Non-specific resistance of mice to infection induced by streptococcus cell walls was found to be dependent on the peptidoglycan activity; cell wall proteins and polysaccharide are inactive. These properties of peptidoglycan resemble those known from endotoxin studies. The data presented suggest the role of peptidoglycan in pathological reactions resulting from host-parasite interaction.
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PMID:Endotoxin-like properties of the peptidoglycan. 12 56

Minicells produced by Bacillus subtilis CU403 (divIVB1) are capable of mucopeptide biosynthesis as shown by the incorporation of L-alanine, D-alanine, and N-acetylglucosamine into trichloroacetic acid-precipitable material, which can be degraded to trichloroacetic acid-soluble material by lysozyme digestion. Incorporation of the precursors is sensitive to vancomycin and D-cycloserine and insensitive to chloramphenicol. Penicillin inhibits the incorporation of D- and L-alanine N-acetylglucosamine at concentrations in excess of 10 mug of penicillin per ml; however, minicells are insensitive to penicillin-induced lysis. The material synthesized in minicells from N-acetylglucosamine is not subject to turnover during a subsequent 6-h incubation period. [2-3H]glycerol is converted to a cold trichloroacetic acid-precipitable form by minicells. This synthesis is not inhibited by vancomycin, penicillin, D-cycloserine, or chloramphenicol. Fractionation of the material synthesized from glycerol into hot trichloroacetic acid-soluble material and chloroform/methanol-extractable material indicates that minicells convert glycerol into teichoic acid and lipid.
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PMID:Synthesis of cell envelope components by anucleate cells (minicells) of Bacillus subtilis. 40 71

An extracellular protein-polysaccharide-lipide (PPL) complex from exponentially growing cultures of Myxococcus virescens was purified by phosphate precipitation and gel chromatography. The high molecular weight slime polymer appeared homogenous upon isoelectric focusing. The PPL complex exhibited proteolytic activity against gelatin and the activity was only partly reduced by heat treatment. The function of the slime polymer as protein denatured was studied. The complex formed micelles similar to anionic detergents and it inhibited the precipitation and coagulation of proteins by trichloroacetic acid. Lysozyme was totally inactivated when treated with the PPL complex. By gel chromatography binding studies, the PPL complex was found to bind lysozyme in the ratio of 1 to 5.8 (w/w). After separation of added protein from the complex the anticoagulation effect on the protein remained. The biological function of the PPL complex was demonstrated with hemoglobin. When all susceptible peptide bonds in PPL-treated hemoglobin were hydrolyzed by trypsin only 20% in the urea-denatured protein were attacked. The combined role of slime and proteolytic activity is discussed.
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PMID:Myxobacterial slime and proteolytic activity. 41 87

Anionic sites on the surface of Brucella canis were visualized in the electron microscope by staining with positively charged ferric oxide hydrosols in acetic acid (AI-reagent), or propanoic acid (PI-reagent), and with a polycationic ferritin derivative. With the AI-reagent, single or small aggregates of ferric oxide particles were bound to the cell surface of Br. canis, whereas, with the lipophilic PI-reagent, the microorganisms were heavily stained with focal aggregates of iron granules. The polycationic ferritin label was uniformly distributed over the entire cell surface of Br. canis. The ferritin label was not bound on the surface of the organisms after prior treatment with trichloroacetic acid or methanolic hydrochloric acid. Treatment with aqueous acetone, chloroform/methanol, diethyl ether, sodium deoxycholate, pronase, lysozyme, hyaluronidase, and sodium periodate neither influenced the morphology of the Brucella nor diminished their ionic binding sites. Our results indicate that the anionic sites on the cell surface of Br. canis may be carboxyl and phosphate groups of lipopolysaccharides.
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PMID:[Ultrastructural investigations on anionic surface sites of Brucella canis (author's transl)]. 60 17

1. Mucins were isolated from sputum from a patient with chronic bronchitis and subjected to two different preparation procedures. 2. In the first procedure, CsBr density-gradient centrifugation gave rise to two well-separated fractions. Mucins recovered in the high-density fraction still contained mucus proteinase inhibitor (MPI) and lysozyme (LSZ). 3. Mucins were purified after a second step of CsBr density-gradient centrifugation or after gel-filtration chromatography with a buffer of high ionic strength, containing 0.5 M NaCl. 4. In the second procedure, trichloroacetic acid treatment of whole sputum followed by cation-exchange chromatography allowed the obtention of a non-retained fraction composed of mucins. 5. Gel-filtration in buffer containing 0.5 M NaCl, allowed the release of MPI and LSZ from mucins, thus confirming that interactions still occurred between those components. 6. The chemical compositions of the mucins isolated by the two above procedures were quite similar. 7. These data support the hypothesis of the existence of ionic interactions between basic amino acid residues of MPI and LSZ and acid residues of the carbohydrate chains of mucins in the secretions of the large airways. 8. These interactions could play a role in the protection of mucins against proteolysis and consequently in the maintenance of rheological properties of the mucus gel in disease.
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PMID:Strong ionic interactions between mucins and two basic proteins, mucus proteinase inhibitor and lysozyme, in human bronchial secretions. 173 97

The effect of a bacteriolytic enzyme, the endo-beta-N-acetylglucosaminidase excreted by Staphylococcus aureus (SaG) on the response of human lymphocytes to mitogens and on the immune response in mice has been studied. SaG inhibited incorporation of [3H]thymidine into TCA-precipitable material by human peripheral lymphocytes stimulated either by phytohemagglutinin or by concanavalin A, as well as formation of cytoplasmic immunoglobulin-containing cells by B lymphocytes treated with pokeweed mitogen. In all cases the level of inhibition first increased with the SaG concentrations reaching values of over 80% at an enzyme concentration of 100 micrograms/ml, and then decreased. Heat-inactivated SaG as well as SaG treated with both polyclonal and monoclonal specific antibodies or enzyme inhibitors such as chitotriose or hydrolyzed peptidoglycan had no effect on lymphocyte response to mitogens. In mice, SaG at a dose of 300 micrograms per mouse was found to cause a fourfold decrease in the anti-BSA antibody titer and an approximately 70-75% reduction in the immunoglobulin-containing cells in the spleens of mice injected with sheep red blood cells. SaG also completely abolished the enhancing effect of adjuvants such as muramyldipeptide, Freund's complete adjuvant, and Escherichia coli lipopolysaccharide. When SaG was injected into mice together with S. aureus peptidoglycan hydrolyzed either by SaG or by human lysozyme, the inhibitory effect on both production of anti-BSA circulating antibodies and appearance of Igc cells in the spleens of mice injected with sheep red blood cells was enhanced. As we know that (a) human tissues contain endo-beta-N-acetylglucosaminidases; (b) other human hexosaminidases (lysozymes) have previously been shown to interfere with the functions of immunocompetent cells; and (c) products of hexosaminidase hydrolysis of peptidoglycan (muropeptides) known to modulate immune response are ordinarily found in the urine of healthy persons, the possibility that hexosaminidases play a major role in the regulation of the immune response is raised and discussed.
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PMID:Staphylococcal endo-beta-N-acetylglucosaminidase inhibits response of human lymphocytes to mitogens and interferes with production of antibodies in mice. 190 69

The kidney plays a major role in the handling of circulating insulin in the blood, primarily via reuptake of filtered insulin at the luminal brush border membrane. 125I-insulin associated with rat renal brush border membrane vesicles (BBV) in a time- and temperature-dependent manner accompanied by degradation of the hormone to trichloroacetic acid (TCA)-soluble fragments. Both association and degradation of 125I-insulin were linearly proportional to membrane protein concentration with virtually all of the degradative activity being membrane associated. Insulin, proinsulin and desoctapeptide insulin all inhibited the association and degradation of 125I-insulin by BBV, but these processes were not appreciably affected by the insulin-like growth factors IGF-I and IGF-II or by cytochrome c and lysozyme, low molecular weight, filterable, proteins, which are known to be reabsorbed in the renal tubules by luminal endocytosis. When the interaction of 125I-insulin with BBV was studied at various medium osmolarities (300-1100 mosM) to alter intravesicular space, association of the ligand with the vesicles was unaffected, but degradation of the ligand by the vesicles decreased progressively with increasing medium osmolarity. Therefore, association of 125I-insulin to BBV represented binding of the ligand to the membrane surface and not uptake of the hormone or its degradation products into the vesicles. Attempts to crosslink 125I-insulin to a high-affinity insulin receptor using the bifunctional reagent disuccinimidyl suberate revealed only trace amounts of an 125I-insulin-receptor complex in brush border membrane vesicles in contrast to intact renal tubules where this complex was readily observed. Both binding and degradation of 125I-insulin by brush border membranes did not reach saturation even at concentrations of insulin approaching 10(-5) M. These results indicate the presence of low-affinity, high-capacity binding sites for 125I-insulin on renal brush border membranes which can clearly distinguish insulin from the insulin-like growth factors and other low molecular weight proteins and polypeptides, but which do not differentiate insulin from its analogues as do the biological receptors for the hormone. The properties and location of these binding sites make them attractive candidates for the sites at which insulin is reabsorbed in the renal tubule.
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PMID:Binding and degradation of 125I-insulin by isolated rat renal brush border membranes: evidence for low affinity, high capacity insulin recognition sites. 306 19


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