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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eosinophils were separated from other types of cells in horse blood or rat peritoneal fluid by centrifugation in concentrated albumin solutions. Eosinophils did not appear to be damaged by this separation procedure. A technique was also devised for isolation of cytoplasmic granules from eosinophils, thus allowing studies on enzyme content of the granules. Granules from both horse and rat eosinophils contained a number of hydrolytic enzymes, similar in variety and in concentration to those previously found in granules of rabbit polymorphonuclear leucocytes. Eosinophil granules differed from those of the rabbit granulocyte in their high content of peroxidase and the absence of lysozyme and phagocytin. On disruption of eosinophil granules by repeated freezing and thawing in saline, cathepsin, ribonuclease, arylsulfatase and beta glucuronidase were released into solution, but phosphatases were partially and peroxidase completely bound to the insoluble granule residue. Peroxidase could be extracted from the granule residue with weak acid. Eosinophil granules thus are lysosome-like structures.
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PMID:ISOLATION OF GRANULES FROM EOSINOPHIL LEUCOCYTES AND STUDY OF THEIR ENZYME CONTENT. 1407 91

The sugar chain-binding specificity of tomato lectin (LEA) against glycoproteins was investigated qualitatively using lectin blot analysis. Glycoproteins containing tri- and tetra-antennary complex-type N-glycans were stained with LEA. Unexpectedly, glycoproteins containing high mannose-type N-glycans and a horseradish peroxidase were stained with LEA. LEA blot analysis of the glycoproteins accompanied by treatment with exoglycosidase revealed that the binding site of LEA for the complex-type N-glycans was the N-acetyllactosaminyl side chains, whereas the proximal chitobiose core appeared to be the binding site of LEA for high mannose-type N-glycans. Despite these results, the glycoproteins did not inhibit the hemagglutinating activity of LEA. Among the chitin-binding lectins compared, potato tuber lectin showed specificity similar to LEA on lectin blot analysis, while Datura stramonium lectin and wheat germ agglutinin (WGA) did not interact with glycoproteins containing high mannose-type N-glycans, except that RNase B was stained by WGA. Based on these observations, LEA blot analysis was applied to sugar chain analysis of tomato glycoproteins. The most abundant LEA-reactive glycoprotein was purified from the exocarp of ripe tomato fruits, and was identified as the tomato anionic peroxidase1 (TAP1). These results suggest that LEA interacts with glycoproteins produced by tomatoes, which participate in biological activities in tomato plants.
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PMID:Analysis of sugar chain-binding specificity of tomato lectin using lectin blot: recognition of high mannose-type N-glycans produced by plants and yeast. 1631 90

Salmonella enterica serovar Enteritidis has emerged during the last 20 years as the major causative agent of food-borne gastroenteritis in humans and as the major infectious agent on poultry farms, replacing Salmonella enterica serovar Typhimurium as the dominant pathogenic serovar. Because adhesion to gut tissues and colonization of the alimentary tract, mediated in large part by the FimH adhesins located on type 1 fimbriae, is an important stage in the pathogenesis of both serovars, the binding properties of the FimH adhesins from these two enteropathogens were compared. Salmonella Enteritidis FimH protein and the Salmonella Typhimurium low-adhesive variant of this adhesin were expressed in Escherichia coli and the recombinant proteins were analysed for their ability to bind glycoproteins carrying different oligomannosidic structures and different types of eukaryotic cells. In static binding assays (ELISA and Western blotting) both FimH proteins bound equally well to all three tested glycoproteins (RNase B, horseradish peroxidase and mannan-BSA). In addition, no differences were found in the binding specificity of the FimH proteins and intact cells of Salmonella Enteritidis and Salmonella Typhimurium to human colon carcinoma or bladder cancer cells. The presence of the same amino acid residues at positions 61 (glycine) and 118 (phenylalanine) and the similar binding properties of these two adhesins suggest that the newly described FimH protein of Salmonella Enteritidis represents the low-adhesive variant found in Salmonella Typhimurium. To study the binding specificity of Salmonella Enteritidis FimH protein further, direct kinetic analysis using surface plasmon resonance was performed. With this method it was found that Salmonella Enteritidis FimH adhesin bound with the highest K(d) value to high-mannose type N-glycans carried by RNase B; about 100 times lower K(d) values were obtained in the interactions with mannan-BSA and horseradish peroxidase.
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PMID:Functional characterization of the FimH adhesin from Salmonella enterica serovar Enteritidis. 1662 51

Protector-II (Pr-II) of the Japanese morning glory (Pharbitis nil Choisy) was inactivated by exposure to polyphenol oxidase. An unidentified protector in the same molecular weight range obtained from sunflower was also inactivated by this enzyme. Earlier speculations that protectors might be lipoprotein in nature were negated by the fact that neither lipase nor protease inactivated the protectors. The protectors were also not inactivated by incubating with alpha-amylase, DNase, or RNase. Catechol mimics Pr and is inactivated by polyphenol oxidase. The oxidation of catechol to o-quinone is accompanied by a loss of chromophores that absorb ultraviolet light and the appearance of a reddish brown color. Similarly, when the relatively low molecular weight auxin protectors (Pr-II class) were incubated with polyphenol oxidase, their oxidation was also frequently associated with the formation of brown color, and oxidation with H(2)O(2) caused a loss of ultraviolet-absorbing chromophores. The data indicate that auxin protectors contain o-dihydroxyphenolic groups at their active site.That o-dihydroxyphenols inhibit indoleacetic acid oxidation has been demonstrated by numerous workers. It is suggested that the high molecular weight auxin protectors and the phenolic compounds described by other authors comprise part of a metabolic system concerned with the regulation of peroxidase-catalyzed redox reactions.
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PMID:Studies on Auxin Protectors: IX. Inactivation of Certain Protectors by Polyphenol Oxidase. 1665 85

Vacuoles were isolated from suspension cultures of sugarcane (Saccharum sp.) cells by centrifugation of protoplasts at high g force against a 12% (w/v) Ficoll solution. Distribution of marker enzymes and Concanavalin A binding showed an 11% contamination of the vacuole preparation by cytoplasmic components, mitochondria, and endoplasmic reticulum, and 18% contamination by plasma membrane. Acid phosphatase, carboxypeptidase, protease, peroxidase, and ribonuclease activities were enriched in isolated vacuoles. Carboxypeptidase was tonoplast-bound, whereas the other enzymes were soluble. Sucrose, reducing sugars, and free amino acids were measured in protoplasts and vacuoles during growth of cells in suspension culture. Sucrose and reducing sugar content of vacuoles increased as the culture aged, while free amino acids decreased sharply.
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PMID:Vacuoles from Sugarcane Suspension Cultures : I. ISOLATION AND PARTIAL CHARACTERIZATION. 1666 93

Ethylene enhanced the senescence of cucumber (Cucumis sativus L. cv ;Poinsett 76') cotyledons. The effect of 10 microliters per liter ethylene was inhibited by 1 millimolar silver thiosulfate, an inhibitor of ethylene action. An increase in proteins with molecular weights of 33 to 30 kilodaltons and lower molecular weights (25, 23, 20, 16, 12, and 10 kilodaltons) were observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels after ethylene enhanced senescence. The measurement of DNase and RNase activity in gels indicated that these new proteins were not nucleases. Two proteins from ethylene-treated cotyledons were purified on the basis of their association with a red chromaphore and subsequently were identified as peroxidases. The molecular weights and isoelectric points (pI) of two of these peroxidases were 33 kilodaltons (cationic, pI = 8.9) and 60 kilodaltons (anionic, pI = 4.0). The observation that [(35)S]Na(2)SO(4) was incorporated into these proteins during ethylene-enhanced senescence suggests that these peroxidases represent newly synthesized proteins. Antibodies to the 33-kilodalton peroxidase precipitated two in vitro translation products from RNA isolated from ethylene-treated but not from control cucumber seedlings. This indicates that the increase in 33-kilodalton peroxidase activity represents de novo protein synthesis. Both forms of peroxidase degraded chlorophyll in vitro, which is consistent with the hypothesis that peroxidases have catabolic or scavenging functions in senescent tissues.
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PMID:Induction of 33-kD and 60-kD Peroxidases during Ethylene-Induced Senescence of Cucumber Cotyledons. 1666 94

T cells recognize protein antigens as short peptides processed and displayed by antigen-presenting cells. However, the mechanism of peptide selection is incompletely understood, and, consequently, the differences in the immunogenicity of protein antigens remain largely unpredictable and difficult to manipulate. In this paper we show that the susceptibility of protein antigens to lysosomal proteolysis plays an important role in determining immunogenicity in vivo. We compared the immunogenicity of proteins with the same sequence (same T cell epitopes) and structure (same B cell epitopes) but with different susceptibilities to lysosomal proteolysis. After immunizing mice with each of the proteins adsorbed onto aluminum hydroxide as adjuvant, we measured serum IgG responses as a physiological measure of the antigen's ability to be presented on major histocompatibility complex class II molecules and to prime CD4+ T cells in vivo. For two unrelated model antigens (RNase and horseradish peroxidase), we found that only the less digestible forms were immunogenic, inducing far more efficient T cell priming and antibody responses. These findings suggest that stability to lysosomal proteolysis may be an important factor in determining immunogenicity, with potential implications for vaccine design.
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PMID:Enhancing immunogenicity by limiting susceptibility to lysosomal proteolysis. 1690 25

To elucidate the deleterious effects of excess lead on radish (Raphanus sativus) cv. Jaunpuri plants were grown in refined sand in complete nutrient solution for 30 days. On the 31st day lead nitrate was superimposed at 0.1 and 0.5mM to radish for 65 days. A set of plants in complete nutrient solution was maintained as control for the same period without lead. Excess Pb at 0.5mM showed growth depression with interveinal chlorosis on young leaves at apex. Excess Pb reduced the fresh and dry weight pronouncedly at d 65. Lead accumulation reduced the concentration of chlorophyll, iron, sulphur (in tops), Hill reaction activity and catalase activity whereas increased the concentration of phosphorus, sulphur (in roots) and activity of peroxidase, acid phosphatase and ribonuclease in leaves of radish.
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PMID:Excess lead alters growth, metabolism and translocation of certain nutrients in radish. 1792 49

A novel, simple and fast method based on a quadrupole ion trap (QIT) and a time-of-flight mass spectrograph was developed for the glycosylation site and glycan structure analysis of glycoprotein by in-solution digestion and in-gel digestion which did not need to enrich and label the glycopeptide. Horseradish peroxidase (HRP) and RNase B were utilised to optimize the conditions of sample pre-processing. The effects of the conditions were investigated separately and the optimal conditions were: heat denaturation of RNase B, chemical denaturation of HRP, RNase B digestion with endoproteinase Lys-C, HRP digestion with trypsin, 12 - 16 h of digestion, 50% acetonitrile-5% trifluoroacetic acid of the extraction solution, sandwich spotting method of the sample.
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PMID:[Sample pre-processing for mass spectrometric analysis of glycoprotein structure]. 1816 9

Despite the therapeutic potential of tempol (4-hydroxy-2,2,6,6-tetra-methyl-1-piperidinyloxy) and related nitroxides as antioxidants, their effects on peroxidase-mediated protein tyrosine nitration remain unexplored. This posttranslational protein modification is a biomarker of nitric oxide-derived oxidants, and, relevantly, it parallels tissue injury in animal models of inflammation and is attenuated by tempol treatment. Here, we examine tempol effects on ribonuclease (RNase) nitration mediated by myeloperoxidase (MPO), a mammalian enzyme that plays a central role in various inflammatory processes. Some experiments were also performed with horseradish peroxidase (HRP). We show that tempol efficiently inhibits peroxidase-mediated RNase nitration. For instance, 10 muM tempol was able to inhibit by 90% the yield of 290 muM 3-nitrotyrosine produced from 370 muM RNase. The effect of tempol was not completely catalytic because part of it was consumed by recombination with RNase-tyrosyl radicals. The second-order rate constant of the reaction of tempol with MPO compound I and II were determined by stopped-flow kinetics as 3.3 x 10(6) and 2.6 x 10(4) M(-1) s(-1), respectively (pH 7.4, 25 degrees C); the corresponding HRP constants were orders of magnitude smaller. Time-dependent hydrogen peroxide and nitrite consumption and oxygen production in the incubations were quantified experimentally and modeled by kinetic simulations. The results indicate that tempol inhibits peroxidase-mediated RNase nitration mainly because of its reaction with nitrogen dioxide to produce the oxammonium cation, which, in turn, recycles back to tempol by reacting with hydrogen peroxide and superoxide radical to produce oxygen and regenerate nitrite. The implications for nitroxide antioxidant mechanisms are discussed.
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PMID:Inhibition of myeloperoxidase-mediated protein nitration by tempol: Kinetics, mechanism, and implications. 1849 4


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