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)

Radioactive selenite reacts with purified human and goat immunoglobulins at acidic and neutral pH. The antigenic properties of the immunoglobulins are retained during the selenium labelling as shown by immunoelectrophoresis and autoradiography. Pepsin digests of 75Se-labelled IgG possess 75Se both in the (Fab')2 fraction and in the low molecular weight peptides derived from the Fc domains. Alpha-1-acid glycoprotein, ribonuclease, and lysozyme are also labelled by this procedure. Enhancement of 75Se incorporation by urea, guanidinium chloride, mercaptoethanol, sodium sulfite and carrier selenite is interpreted as an effect of destabilization of IgG disulfide bonds. Up to 1.4 g atoms Se per mol IgG have been incorporated. We assume that selenite is cleaving disulfides by a process akin to sulfitolysis. The lability of the isolated 75Se-labelled IgG to high concentrations of mercaptans and sulfite is consistent with this idea. These 75Se-labelled proteins may be useful in structure studies and radioimmunoassay.
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PMID:Reaction of selenium with immunoglobulin molecules. 1 84

1. The sequence of renal cellular membrane damage induced by gentamicin was studied in the rat by using the release of alkaline phosphatase, acid phosphatase, muramidase and protein from renal cells as indices of renal damage. 2. The protective effect of a combination of vitamin E and selenium against renal damage was also investigated. 3. Gentamicin (60 mg kg-1 body weight) was nephrotoxic within 12 h of the first dose. 4. The plasma membrane of the renal tubules is damaged before the lysosomal membrane is affected. 5. A combination of vitamin E (1 mg g-1 body weight) and selenium (4 x 10(-3) mg g-1 body weight) attenuates the renal damage induced by gentamicin. Results suggest synergism between vitamin E and selenium in attenuating the renal damage. The possible mechanism of attenuation is discussed. 6. Vitamin E and selenium may have anti-diuretic potential.
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PMID:Vitamin E and selenium in gentamicin nephrotoxicity. 226 Dec 41

Lymphoproliferative responses to phytohaemagglutinin and other phytolectins declined following prolonged exposure of lambs to a diet deficient in both selenium and vitamin E, coinciding with the development of nutritional myopathy. Supplementation restored lymphocyte responses within a week and led to a rapid decline in circulating activity of the muscle enzyme creatine kinase in serum. Lymphocyte responses of the dams remained largely unaltered throughout the experiment. There was no evidence of erythrocyte damage in myopathic lambs, concentrations of serum IgG, IgM and lysozyme were similar to those in healthy lambs, and chemiluminescence tests on whole blood samples failed to reveal a phagocytic defect in response to particulate and non-particulate stimuli. However, serum from myopathic lambs did show a reduced opsonic capacity.
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PMID:Immunological malfunctions associated with low selenium-vitamin E diets in lambs. 231

Influence of supplemental Se on humoral immune response was measured in 60 weaned beef calves with marginal blood Se status. Calves were fed a Se-deficient diet consisting of corn silage, corn grain, and soybean meal. Blood Se concentrations, primary and secondary humoral immune responses to hen egg lysozyme inoculation, and weight gain were determined in a 70-day trial. Calves fed 20 mg of Se/kg of mineral mixture ad libitum had lower antibody responses (P less than 0.02), compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, IM, or with calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture. Calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture had higher (P less than 0.001) blood Se concentrations on day 70, compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, IM. Selenium supplementation had no effect on weight gain.
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PMID:Influence of supplemental selenium on humoral immune responses in weaned beef calves. 280 10

The capability of dietary selenium (Se) to augment the immune response was evaluated in 96 crossbred weanling swine. Six groups of 16 pigs were fed diets with Se supplemented as sodium selenite at 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mg/kg. The basal diet contained 0.068 mg of Se/kg. Weight gain, feed consumption, and feed efficiency were similar for all diets. Whole blood concentrations of Se linearly increased as the dietary concentrations of Se increased. The humoral response was monitored by immunoglobulin G titers to lysozyme and ribonuclease, using an enzyme-linked immunosorbent assay. Although no significant difference in immunoglobulin G titers to either antigen was detected among diets, a similar trend in antibody response was noted. The diet with 0.9 mg of added Se/kg produced the highest antibody response to both antigens, whereas the diet with 0.3 mg of added Se/kg produced the lowest titers for both antigens. Cell-mediated immunity was evaluated in the pigs by the dermal response to phytohemagglutinin. Significant difference was not detected in pigs fed the various diets in terms of the mean diameters of their dermal reactions to phytohemagglutinin injections. Although blood concentrations of Se were increased, rate and efficiency of weight gain and humoral and cell-mediated immunity were not significantly improved by adding 0.3 to 1.5 mg of Se/kg to diets.
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PMID:Immunomodulation in weanling swine with dietary selenium. 348

Previous 77Se NMR relaxation time studies established the utility of 77Se NMR spectroscopy in studying low molecular weight (less than 500) selenium-containing molecules. Since the spin rotation and chemical shift anisotrophy mechanisms contributed significantly to the 77Se spin-lattice relaxation in these compounds, it was questionable as to whether the latter mechanism would be efficient enough to enable 77Se resonances to be observed in a reasonable period in high molecular weight selenobiomolecules. Thus, to address this problem, disulfide bonds of ribonuclease-A and lysozyme were reductively cleaved under denaturing conditions, and the resulting 7-8 sulfhydryl groups were treated with a new sulfhydryl group reagent containing selenium, 6,6'-diselenobis(3-nitrobenzoic acid), to give proteins containing covalently attached selenium in the form of selenenyl sulfides. The observation of high resolution 77Se NMR spectra of these proteins under denaturing conditions was accomplished. Five to six 77Se NMR resonances, which fell in a chemical shift range of 14-15 ppm, were observed for each protein and are compared to the chemical shifts of several model selenenyl sulfides derived from cysteine.
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PMID:Demonstration of the feasibility of observing nuclear magnetic resonance signals of 77Se covalently attached to proteins. 627 74

The labilizing effect of gentamicin, an aminoglycoside antibiotic, on isolated rat kidney lysosomes was investigated. The light-scattering behavior of lysosomal suspensions and the release of lysosomal acid hydrolase enzymes (acid phosphatase, beta-glucuronidase and muramidase) from incubated lysosomal suspensions, in the presence of gentamicin, were used as indices of lysosomal membrane labilization. Gentamicin was found to cause a decrease in light absorbance and a release of lysosomal acid hydrolases, which indicate lysosomal membrane swelling. In the presence of selenium, in the form of potassium selenate, the decrease in light absorbance of lysosomal suspensions and the release of lysosomal acid hydrolases from isolated lysosome particles were reduced markedly. This suggests that selenium protects against gentamicin-induced lysosomal membrane labilization. The possible mechanisms of protection by selenium are discussed.
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PMID:Studies on gentamicin-induced labilization of rat kidney lysosomes in vitro. Possible protection by selenium. 662 37

Gentamicin has been shown to induce renal tubular damage in man and laboratory animals and to result in elevated urinary excretion of some enzymes associated with specific cell regions in the kidney. In the present investigation, the possible protective effect of selenium against gentamicin-induced renal damage was tested by measuring the urinary excretion of some enzymes in the presence and absence of selenium. Our results show that a prior subcutaneous injection of selenium to rats for two days followed by a simultaneous S.C. injection of gentamicin and selenium resulted in a marked reduction in the excretion of such biochemical systems as the urine volume, urinary proteins, alkaline and acid phosphatases, beta-glucuronidase, muramidase, and glutamate dehydrogenase. Renal functional studies revealed that selenium-treated rats suffered less adverse effects compared to rats treated with gentamicin alone. Urinary acid phosphatase, beta-glucuronidase and muramidase, the three lysosomal enzymes tested, appeared to respond most readily to protection by selenium.
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PMID:Protection by selenium against gentamicin-induced acute renal damage in the rat. 672 37

1. The synthesis described is of p-azidophenylglyoxal (p-APG) by diazotization of p-aminoacetophenone to an intermediate which when reacted with sodium azide gives p-azidoacetophenone; oxidation of the latter with selenium dioxide gives rise to p-APG (corrected melting point, 103-105 degrees C). The phenylglyoxal moiety was designed to react with arginine residues, whereas the p-azidoaryl function generates a reactive nitrene when activated with UV light; p-APG reacts most selectively with arginine and to a lesser extent with cystine and histidine. 2. p-APG has absorption peaks at 205 and 280 nm which decrease on photolysis. 3. Bovine heart lactic dehydrogenase, egg white lysozyme, horse liver alcohol dehydrogenase, and yeast alcohol dehydrogenase, all enzymes having arginyl residues at their active sites, are inhibited by p-APG in the dark. 4. Gel electrophoresis of oligomeric enzymes having arginyl residues at their active sites and exposed to p-APG and to UV irradiation gave varying proportions of monomers and photocross-linked dimers, trimers, tetramers, and larger molecular weight aggregates.
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PMID:p-Azidophenylglyoxal. A heterobifunctional photoactivable cross-linking reagent selective for arginyl residues. 702 66

Effects of selenium (Se) deficiency and supplementation on production of colostral immunoglobulins by beef cows and transfer of antigen-specific and nonspecific immunoglobulins to their calves were examined. Eight beef cows, with marginal to deficient Se status (blood Se concentration, 50 micrograms/L), were allotted by breed and age to 1 of 4 Se treatment groups (n = 20/group): no supplemental Se; parenteral administration of 0.1 mg of Se and 1 mg of vitamin E/kg of body weight; ad libitum consumption of 120 mg of Se/kg of salt-mineral mix (SMM); and parenteral administration of 0.1 mg of Se and 1 mg of vitamin E/kg plus ad libitum consumption of 120 mg of Se/kg of SMM. All cows were inoculated IM with lysozyme. Cows consumed Se-deficient pastures or hay (21 to 62 micrograms/kg) during the study that began at mid-gestation and ended at postpartum hour 24. Although the concentration of specific lysozyme antibodies was not affected, cows given 120 mg of Se/kg of SMM (treatments 3 and 4) had higher colostral IgG concentration (P < 0.002) than did Se-deficient cows (treatments 1 and 2). Calves from cows in treatments 3 and 4 had higher postsuckle serum concentrations of IgG (P < 0.01) than did calves from cows in treatments 1 and 2. Colostral IgM and calf serum IgM concentrations did not differ among treatments.
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PMID:Effect of selenium supplementation on colostral IgG concentration in cows grazing selenium-deficient pastures and on postsuckle serum IgG concentration in their calves. 778 20


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