Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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)
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PMID:Design for cell-specific targeting of proteins utilizing sugar-recognition mechanism: effect of molecular weight of proteins on targeting efficiency. 778 35

Photosensitization of lysozyme, liposomes, ghosts and intact red blood cells (RBC) was investigated for aqueous hypericin. The effects of azide ion, 1,4-diazabicyclo(2.2.2)octane, and superoxide dismutase on photosensitized inactivation of lysozyme in 0.5% Triton X-100 indicate that singlet oxygen is the major inactivating intermediate with a contribution from superoxide. The singlet oxygen quantum yield (phi delta) scaled to methylene blue is 0.49 +/- 0.06 at monochromatic wavelengths from 514 to 600 nm. Relative values of phi delta based on lysozyme inactivation for different vehicles are: 0.5% Triton X-100 (1.13), human serum albumin (0.65), Cremophor-EL (0.76), Cremophor-RH40 (0.98), egg phosphatidylcholine (EPC) liposomes (0.04), hydrogenated soy phosphatidylcholine (HSPC) liposomes (< 0.01). Hypericin photosensitized lipid peroxidation of EPC liposomes and RBC ghosts. Extensive cross-linking of ghost membrane proteins occurred during the initial stages of lipid peroxidation. Prompt photohemolysis was used as the assay of RBC membrane damage. The photohemolysis curves are modeled with multihit target theory based on the "hit number" (n) and the target cross section (v). The values of v and the conventional "1/t50" parameter are equivalent determinants of the photohemolysis rate. The photohemolysis curves are in good agreement with n = 15 for incubation in phosphate-buffered saline at different hypericin concentrations and with additives. The measurements for other vehicles led to n = 19 for Cremophor-EL and n = 3 for EPC and HSPC liposomes, indicating that the kinetics of photohemolysis depend on the conditions of incubation.
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PMID:Hypericin photosensitization in aqueous model systems. 812 39

Two types of superoxide dismutase (SOD) have been found in Brucella abortus, a cytosolic Mn-SOD and a Cu/Zn-SOD of unknown location. We sought to determine the subcellular location of Cu/Zn-SOD in B. abortus ST 19. We report a modified spheroplasting procedure for the release of periplasmic contents from B. abortus cells using a dipolar ionic detergent, Zwittergent 316. This detergent, used in place of EDTA, destabilizes the outer membrane sufficiently to allow penetration of lysozyme and the subsequent selective release of periplasmic proteins by osmotic shock. Cytoplasmic cross-contamination of periplasmic fractions was assessed by assaying for malate dehydrogenase activity. Cyanide-sensitive and cyanide-insensitive SOD activity was measured by both the xanthine oxidase-cytochrome c method and a hematoxylin assay. Results suggest that B. abortus Cu/Zn-SOD activity is periplasmic. This zwittergent-lysozyme extraction procedure may be applicable to the separation, isolation and characterization of many other periplasmic proteins of B. abortus and other Gram-negative organisms especially when cytosolic contamination is undesirable.
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PMID:Periplasmic location of Brucella abortus Cu/Zn superoxide dismutase. 816 Mar 46

In the present investigation alterations in the free radical generating and scavenging enzymes in platelets, neutrophils (PMNLs), heart and lung homogenates following rat pulmonary thromboembolism have been studied. Thrombosis was induced by intravenous infusion of collagen and adrenaline. Levels of malonaldehyde (MDA) were elevated in the PMNLs after thrombosis. Activities of superoxide dismutase (SOD) and catalase (CAT) were found to increase in platelets and PMNLs respectively. However, there was no significant alteration in the lactate dehydrogenase (LDH), lysozyme (LYS), ratio of xanthine oxidase to dehydrogenase (XO/XH) and PMNLs O2- generation before and after thrombosis. Migration of PMNLs following thrombosis was indicated by increased activity of myeloperoxidase (MPO) in the heart. In addition, pretreatment with allopurinol, a xanthine oxidase inhibitor and indomethacin, a cyclooxygenase inhibitor offered protection against thromboembolism induced death/paralysis. Results suggest the involvement of free radicals in thrombosis.
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PMID:Free radical scavenging mechanisms during pulmonary thromboembolism in rats. 846 69

Constant pressure and temperature molecular dynamics techniques have been employed to investigate the changes in structure and volumes of two globular proteins, superoxide dismutase and lysozyme, under pressure. Compression (the relative changes in the proteins' volumes), computed with the Voronoi technique, is closely related with the so-called protein intrinsic compressibility, estimated by sound velocity measurements. In particular, compression computed with Voronoi volumes predicts, in agreement with experimental estimates, a negative bound water contribution to the apparent protein compression. While the use of van der Waals and molecular volumes underestimates the intrinsic compressibilities of proteins, Voronoi volumes produce results closer to experimental estimates. Remarkably, for two globular proteins of very different secondary structures, we compute identical (within statistical error) protein intrinsic compressions, as predicted by recent experimental studies. Changes in the protein interatomic distances under compression are also investigated. It is found that, on average, short distances compress less than longer ones. This nonuniform contraction underlines the peculiar nature of the structural changes due to pressure in contrast with temperature effects, which instead produce spatially uniform changes in proteins. The structural effects observed in the simulations at high pressure can explain protein compressibility measurements carried out by fluorimetric and hole burning techniques. Finally, the calculation of the proteins static structure factor shows significant shifts in the peaks at short wavenumber as pressure changes. These effects might provide an alternative way to obtain information concerning compressibilities of selected protein regions.
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PMID:Intrinsic compressibility and volume compression in solvated proteins by molecular dynamics simulation at high pressure. 887 83

Lymphocyte reactivity against hepatitis C virus (HCV) antigens was studied in 20 couples in which 1 member had chronic hepatitis C. This was done to investigate the possibility of HCV transmission between spouses that was not followed by seroconversion. Twenty healthy subjects without any risk factors for HCV transmission served as negative controls. All the patients' spouses and the healthy controls were negative for HCV RNA and for anti-HCV antibody. Lymphocytes were cultured with recombinant HCV core and nonstructural antigens (c22, c33, c100, c200, and NS5) and with control antigens (sperm whale myoglobin, chicken lysozyme, and superoxide dismutase). Lymphocytes from 10 patients and 4 seronegative spouses proliferated in the presence of at least one HCV antigen. No proliferation was shown with nonspecific antigens or in the control group. This study gives evidence for possible in vivo priming with HCV antigens that did not lead to seroconversion in spouses of HCV-positive patients.
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PMID:Lymphocyte reactivity to hepatitis C virus (HCV) antigens shows evidence for exposure to HCV in HCV-seronegative spouses of HCV-infected patients. 923 22

Both PAF (10 microM) and bradykinin (0.1-10 microM) increased lysozyme (from submucosal gland serous cells (+138 and +45% for PAF, 10 microM, and bradykinin, 1 microM, respectively) and albumin (mainly active epithelial transport; +387 and +108%) outputs into the ferret tracheal lumen in vitro and reduced the negativity of the potential difference (PD: -33 and -17%) across the trachea. Since PAF can cause bronchial smooth muscle hyperresponsiveness, we tested whether these effects were interactive, and if PAF would increase the actions of bradykinin. The bradykinin-induced lysozyme and albumin outputs were more than trebled and the PD change was enhanced by PAF, after the immediate secretory effects of the latter had returned to baseline. The secretory and PD responses to PAF were all prevented by the PAF-antagonist WEB 2086 and by a combination of the free-radical scavengers catalase and SOD, indicating that PAF may act on specific receptors to release free-radicals. Nedocromil sodium inhibited the increase in lysozyme and albumin outputs produced by PAF, but had no effect on the PD response. None of the tracheal responses to bradykinin was modified by WEB 2086, catalase and SOD, or nedocromil sodium. The secretory and PD hyperresponsiveness to bradykinin caused by PAF was prevented by WEB 2086 and by catalase and SOD. Nedocromil sodium greatly inhibited the lysozyme and albumin hyperresponsiveness but had no effect on the PD response. Thus PAF may release more than one type of radical which have differential effects on serous cells and albumin transport compared with PD; nedocromil sodium may act only against the radical causing the secretory effects.
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PMID:PAF-induced secretory hyperresponsiveness in the ferret trachea to bradykinin and its pharmacological inhibition. 951 26

Endospores of Bacillus subtilis are enclosed in a proteinaceous coat which can be differentiated into a thick, striated outer layer and a thinner, lamellar inner layer. We found that the N-terminal sequence of a 25-kDa protein present in a preparation of spore coat proteins matched that of the Mn-dependent superoxide dismutase (SOD) encoded by the sod4 locus. sod4 is transcribed throughout the growth and sporulation of a wild-type strain and is responsible for the SOD activity detected in total cell extracts prepared from B. subtilis. Disruption of the sod4 locus produced a mutant that lacked any detectable SOD activity during vegetative growth and sporulation. The sodA mutant was not impaired in the ability to form heat- or lysozyme-resistant spores. However, examination of the coat layers of sodA mutant spores revealed increased extractability of the tyrosine-rich outer coat protein CotG. We showed that this condition was not accompanied by augmented transcription of the cotG gene in sporulating cells of the sodA mutant. We conclude that SodA is required for the assembly of CotG into the insoluble matrix of the spore and suggest that CotG is covalently cross-linked into the insoluble matrix by an oxidative reaction dependent on SodA. Ultrastructural analysis revealed that the inner coat formed by a sodA mutant was incomplete. Moreover, the outer coat lacked the characteristic striated appearance of wild-type spores, a pattern that was accentuated in a cotG mutant. These observations suggest that the SodA-dependent formation of the insoluble matrix containing CotG is largely responsible for the striated appearance of this coat layer.
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PMID:Involvement of superoxide dismutase in spore coat assembly in Bacillus subtilis. 957 76

Electrostatic interactions play a key role in many aspects of protein engineering. Consequently, much effort has been put into the design of software for calculating electrostatic fields around macromolecules. We show that optimization of hydrogen bonding networks can improve both the results of pK(a) calculations and the results of electrostatic calculations performed by commonly used programs such as DelPhi. Further optimization can often be achieved by flipping the side chains of asparagine, histidine and glutamine around their chi2, chi2 and chi3 torsion angles, respectively, when this improves the local hydrogen bonding network. These optimizations are applied to some well characterized proteins: BPTI, hen egg white lysozyme and superoxide dismutase. A search for flipped residues in the PDB revealed that significant improvements in electrostatic calculations in or near the active site of enzymes can be expected for about one quarter of all enzymes in the PDB.
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PMID:Improving macromolecular electrostatics calculations. 1046 26

A recombinant strain of Aspergillus niger (B1-D), engineered to produce the marker protein hen egg white lysozyme, was investigated with regard to its susceptibility to "oxidative stress" in submerged culture in bioreactor systems. The culture response to oxidative stress, produced either by addition of exogenous hydrogen peroxide or by high-dissolved oxygen tensions, was examined in terms of the activities of two key defensive enzymes: catalase (CAT) and superoxide dismutase (SOD). Batch cultures in the bioreactor were generally found to have maximum specific activities of CAT and SOD (Umg x protein(-1)) in the stationary/early-decline phase. Continuous addition of H2O2 (16 mmole L(-1) h(-1)), starting in the early exponential phase, induced CAT but did not increase SOD significantly. Gassing an early exponential-phase culture with O2 enriched (25 vol%) air resulted in increased activities of both SOD and CAT relative to control processes gassed continuously with air, while gassing the culture with 25 vol% O2 enriched air throughout the experiment, although inducing a higher base level of enzyme activities, did not increase the maximum SOD activity obtained relative to control processes gassed continuously with air. The profile of the specific activity of SOD (U mg CDW(-1)) appeared to correlate with dissolved oxygen levels in processes where no H2O2 addition occurred. These findings indicate that it is unsound to use the term "oxidative stress" to encompass a stress response produced by addition of a chemical (H2O2) or by elevated dissolved oxygen levels because the response to each might be quite different.
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PMID:"Oxidative stress" response in submerged cultures of a recombinant Aspergillus niger (B1-D). 1106 35


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