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)

Salt treatment of the cytoplasmic estradiol-receptor complex from chick oviduct induces a strong affinity of the complex for DNA-cellulose and phenyl-sepharose. This process is called activation. Binding to heparin- and lysozyme-sepharose is also observed with the untreated complex. But, the salt treatment, additional binding of the complex to these adsorbents is seen. The increased ability of the complex to bind to polyanions and polycations is destroyed by mild trypsination. The binding to the hydrophobic adsorbent is not affected by this treatment. Neither a change of the sedimentation constant nor of the size of the receptor protein is observed after salt treatment in the cold. After binding of the salt-activated estradiol-receptor complex to DNA-cellulose in the cold, an increase of its sedimentation constant and its size, as measured by density-gradient centrifugation and agarose gel chromatography, resp., becomes apparent. A similar phenomenon is observed after binding to DEAE-cellulose and to some extent after binding to heparin-sepharose. The nuclear complex seems to have the same sedimentation constant as the cytoplasmic complex eluted from DNA-cellulose. The sedimentation constant of the nuclear complex is not changed after DNA-cellulose chromatography. The cytoplasmic progesterone-receptor complex from the same tissue, i.e. the oviduct, does not show any change of size. Thus the well-known process of transformation can now be separated into 2 steps. (1) Activation of the estradiol-receptor complex for its binding to various adsorbents in vitro and probably to its acceptor site(s) in vivo. (2) Increase of receptor size. This second step seems to be a special property of the estradiol-receptor complex. Its physiological significance is unclear.
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PMID:Transformation of the estrogen-receptor complex from chick oviduct in 2 steps. 720 34

An esterase activity hydrolyzing palmitoyl-CoA was released into the culture medium from Mycobacterium smegmatis. Although another esterase activity hydrolyzing Tween 20 (polyoxyethylene sorbitan monolaurate) was also found in the culture medium, the bulk of the esterase activity was retained in the cells. However, treatment of early-log phase cells with lysozyme to prepare ghosts released 80% of the Tween 20 hydrolyzing activity, indicating the localization of the esterase in the periplasmic space or the cell envelope fraction. The presence of two different esterases hydrolyzing palmitoyl-CoA and Tween 20, suggested by the above results, was confirmed by the separation of these esterases on phenyl-Sepharose column chromatography. Palmitoyl-CoA hydrolase (thioesterase) was purified 630-fold from lysozyme-treated supernatant fluid to homogeneity, by means of Sephadex G-100 gel filtration, and DEAE-cellulose, phenyl-Sepharose and Blue-Agarose column chromatographies. Its molecular weight was approximately 42,000. Tween hydrolase was partially purified 150-fold by the same purification procedure up to the step of phenyl-Sepharose chromatography and its molecular weight was found to be about 51,000. These activities were stable against heating at 60 degrees C and treatment with non-ionic detergents. Thioesterase hydrolyzed long chain acyl-CoAs (C12-C20), but not Tween 20-80 or beta-naphthyl acetate. On the other hand, Tween hydrolase hydrolyzed Tween 20-80 and beta-naphthyl acetate. On the other hand, Tween hydrolase hydrolyzed Tween 20-80 and beta-naphthyl acetate, but not acyl-CoAs. Both esterases hydrolyzed monoolein, but not diolein, triolein, or phosphatidylcholine.
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PMID:Two esterases released from Mycobacterium smegmatis from the hydrolysis of long chain acyl-CoAs and Tween. 733 1

Precipitation by ammonium sulfate and a subsequent purification of the culture fluid of Actinomyces levoris by gel-filtration through Sephadex G-25, ion-exchange chromatography on DEAE-cellulose and CM-cellulose resulted in an enzyme which activley lyzes the cell walls of a hemolytic streptococcus of group A. The molecular weight (12,500), isoelectric point (pI 10,6) and amino acid composition of the enzyme were determined. The enzyme specificity was assayed using peptidoglycane isolated rom the cell walls of streptococcus of group A used as a substrate. An analysis of the hydrolysis products of peptidoglycane showed that the enzyme under study is an endo-beta-N-acetylmuramidase (EC 3.2.1.17).
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PMID:[Isolation and characterization of endo-N-acetylmuramidase produced by Actinomyces levoris]. 738 73

Two proteinaceous lysozyme inhibitors, hen-egg-white lysozyme inhibitors F-I and F-II, were isolated from the culture broth of a bacterial strain identified as Pseudomonas aeruginosa M-1001. Maximum lysozyme inhibitory activity was obtained when the bacterium was grown aerobically in a medium consisting of 0.25% glucose, 0.25% beef extract, 0.25% polypepton, 1.0% sodium L-glutamate, and 1.0% soluble starch (pH 7.0) at 37 degrees C after 20-24 hrs. F-I and F-II were purified 20 and 7.5-fold, respectively, from the culture supernatant of P. aeruginosa M-1001 by ammonium sulfate fractionation, DEAE-Sepharose CL-6B column chromatography, and Sephacryl S-200 gel chromatography. The molecular weights of F-I and F-II were estimated to be about 57,000 and 33,000, by SDS-PAGE, respectively. F-I was stable in a pH range between 6 and 10 and below 50 degrees C. F-II was stable in a pH range between 6 and 11 and below 40 degrees C. Many Gram-positive bacteria were found to be inhibited by the crude lysozyme inhibitors.
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PMID:Production, purification and characterization of two proteinaceous hen-egg-white lysozyme inhibitors from Pseudomonas aeruginosa M-1001. 748 Mar 63

Histidine, histamine and polymyxin B affinity sorbents were employed for the removal of Escherichia coli-derived endotoxins. Their effectiveness was compared with those of poly-L-lysine-Sepharose and DEAE-Sepharose. All sorbents reduced the concentration of endotoxins from an E. coli culture filtrate to tolerable levels. However, their effectiveness was not higher than that of the anion exchanger, which displayed clearance rates of up to 15,000. Endotoxin removal from protein solutions depended on the net charge of the desired protein. Lysozyme as a model for positively charged proteins enhanced endotoxin removal. In contrast, only low initial contamination levels (< 34 EU/ml) were reduced to tolerable levels from bovine serum albumin (BSA) as the negatively charged protein model owing to competition of BSA and endotoxins for adsorption sites. Hence also a low BSA recovery was observed after the treatment whereas the lysozyme recovery was almost 100%. At pH values below the isoelectric point of BSA, endotoxin removal was also more effective. The best conditions for the decontamination were found at neutral pH and low ionic strength (< or = 20 mM phosphate). Ionic forces between ligands and endotoxins are dominant at this ionic strength; hydrophobic interactions are not very effective. Hence the selectivities of all sorbents towards endotoxins are not exceptionally high. DEAE-anion exchangers are the most suitable sorbents for the removal of endotoxins from solutions accommodating positively charged proteins owing to their low cost and high capacity. Poly-L-lysine-Sepharose was most effective for the removal of small amounts of endotoxins from solutions of negatively charged proteins. The "affinity ligands" histamine, histidine and polymyxin B were effective for the removal of endotoxins from E. coli filtrate; however, their effectiveness decreased dramatically in the presence of BSA and it was lower than for poly-L-lysine- and DEAE-Sepharose in the presence of lysozyme.
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PMID:Removal of endotoxins by affinity sorbents. 749 97

Protein disulfide isomerase (PDI), which catalyses the folding of newly synthesized or denatured proteins through correct disulfide formation, was purified from soybean (Glycine max). The enzyme was purified 12,000-fold over crude extracts to apparent homogeneity in six purification steps: 60-70% ammonium sulfate fractionation, and chromatography on DEAE Toyopearl 650M, Q-Sepharose Fast Flow, Hiload Superdex 200 pg, Phenyl Sepharose HP, and TSK G-3000 SW. The native enzyme had a molecular weight of 120 kDa on gel filtration. Subunit molecular weight was estimated as 63 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, thus indicating the enzyme to be comprised of two identical subunits. The enzyme pH optimum was 8.0 with reactivation of scrambled RNase, and the pI 7.65. The N-terminal amino acid sequence of soybean PDI was homologous to that of mature alfalfa as deduced from the cDNA sequence. Two identical active site sequences, APWCGHCK, were obtained from different proteolytic peptide fragments of soybean PDI. Soybean PDI facilitated reactivation not only of scrambled RNase, but denatured and reduced lysozyme and the Bowman Birk soybean trypsin inhibitor as well. This is the first report to appear on the the purification, characterization and amino acid sequence analysis of the active site of a plant PDI.
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PMID:Purification and characterization of protein disulfide isomerase from soybean. 777 91

Bacterial autolysins are endogenous enzymes that specifically cleave covalent bonds in the cell wall. These enzymes show both substrate and bond specificities. The former is related to their interaction with the insoluble substrate whereas the latter determine their site of action. The bond specificity allows their classification as muramidases (lysozymes), glucosaminidases, amidases, and endopeptidases. To demonstrate that the autolysin (LYC muramidase) of Clostridium acetobutylicum ATCC824 presents a domainal organization, a chimeric gene (clc) containing the regions coding for the catalytic domain of the LYC muramidase and the choline-binding domain of the pneumococcal phage CPL1 muramidase has been constructed by in vitro recombination of the corresponding gene fragments. This chimeric construction codes for a choline-binding protein (CLC) that has been purified using affinity chromatography on DEAE-cellulose. Several biochemical tests demonstrate that this rearrangement of domains has generated an enzyme with a choline-dependent muramidase activity on pneumococcal cell walls. Since the parental LYC muramidase was choline-independent and unable to degrade pneumococcal cell walls, the formation of this active chimeric enzyme by exchanging protein domains between two enzymes that specifically hydrolyse cell walls of bacteria belonging to different genera shows that a switch on substrate specificity has been achieved. The chimeric CLC muramidase behaved as an autolytic enzyme when it was adsorbed onto a live autolysin-defective mutant of Streptococcus pneumoniae. The construction described here provides experimental support for the theory of modular evolution which assumes that novel proteins have evolved by the assembly of preexisting polypeptide units.
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PMID:Interchange of functional domains switches enzyme specificity: construction of a chimeric pneumococcal-clostridial cell wall lytic enzyme. 793 8

We have analysed some operational parameters for two novel adsorbents intended for recovery of proteins from particle-containing feedstocks using expanded bed adsorption. The adsorbents tested were STREAMLINE DEAE and STREAMLINE SP, ion exchangers based on an agarose/crystalline quartz composite. Parameters analysed included bed expansion, adsorption efficiency, washing and elution. Bed expansion was considerably lower for STREAMLINE adsorbents compared to conventional agarose based media, higher flow velocities were thus possible during the expanded bed process. Breakthrough capacity was 63 mg ml-1 for lysozyme on STREAMLINE SP and 36 mg ml-1 for bovine serum albumin on STREAMLINE DEAE at a flow velocity of 300 cm h-1. To achieve high breakthrough capacity, the sedimented bed height should be at least 10 cm. Furthermore, breakthrough capacity increased to some extent when temperature was increased from room temperature to 36 degrees C, a phenomenon which can be useful in some processes. The number of living E. coli cells in the effluent was reduced by a factor of 10(5) after washing with 15 sedimented bed volumes. The optimal flow velocity for elution was 100 cm h-1 considering time for elution and volume of the eluted fraction. Flow direction during elution in packed bed mode had little impact on the elution volume, however, elution in expanded bed mode increased the volume by approx. 40%. The data presented on the performance of STREAMLINE adsorbents show that they are very useful for recovery of proteins from particle-containing feedstocks using expanded bed adsorption.
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PMID:Analysis of some operating parameters of novel adsorbents for recovery of proteins in expanded beds. 854 17

Lysozyme in the urine of a hemodialysis patient was purified in two steps: DEAE Sephadex chromatography followed by Sephacryl chromatography. The Sephacryl S-100 column chromatographed fraction showing lytic activity was proven to give one band on SDS-PAGE and to have a molecular mass of 14500, in agreement with that of lysozyme. The N-terminal amino acid sequence of this purified protein was identical to that of lysozyme. These results indicate that the protein purified was indeed lysozyme. The specific affinity of lysozyme for Sephacryl S-100 may explain the greater purity of the same protein isolated by this method.
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PMID:Effective method for purification of lysozyme from human urine. 893 Jul 49

Surface-modified flat-sheet microfiltration membranes were functionalised with poly-L-lysine, polymyxin B, poly(ethyleneimine), L-histidine, histamine, alpha-amylase and DEAE as well as deoxycholate. Their suitability to remove endotoxin from both buffers and protein solutions was examined using bovine serum albumin, murine IgG1 and lysozyme as model proteins. In protein-free solutions reduction from 6000 EU/ml to <0.1 EU/ml was achieved with all applied ligands; only alpha-amylase as well as L-histidine and histamine, when immobilized via the non-ionic spacer bisoxirane, exhibited low clearance factors at neutral pH. The adsorption of endotoxin is mainly ruled by electrostatic interaction forces. Thus in multi-component systems, such as endotoxin-contaminated protein solutions, competing interactions take place: acidic proteins compete with endotoxin for binding sites at the membrane adsorbers, basic proteins compete with the ligands for endotoxin and act as endotoxin carriers. With properly chosen conditions the membrane adsorbers presented here show exceptional effectiveness also in the presence of proteins. They are generally superior to functionalised Sepharose chromatographic sorbents and allow fast processing. They may contribute to reduce the risks in the application of parenterals and diagnostics.
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PMID:Membrane adsorbers for selective removal of bacterial endotoxin. 920 May 21


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