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

---

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

A quick and simple method has been developed for the recovery of proteins from water-in-oil microemulsions (w/o-MEs), which is needed to further the use of liquid-liquid extraction in bioseparations. By adding a small portion (0.1 v/v or less) of cosurfactant (e.g., 1-alkanol) to w/o-ME solution, proteins were readily expelled, sometimes as solids, while most or all of the surfactant (Aerosol OT) remained in solution. The release of proteins increased with the further addition of cosurfactant and was greater when the molar ratio of protein to w/o-ME or fractional occupancy (f) was high. However, protein expulsion was also significant when f was small. The addition of cosurfactant released ribonuclease, lysozyme, alpha-chymotrypsin, pepsin, bovine serum albumin (BSA), and catalase from w/o-ME solution, but the expulsion was greater for BSA relative to chymotrypsin and lysozyme. Protein expulsion also increased with cosurfactant chain length for the homologous series of 1-alkanols starting at 1-butanol; however, water was also coexpelled in significant amounts. An exception to the latter rule was 1-butanol, which readily promoted the release of protein, but not encapsulated water. The addition of 1-butanol to a w/o-ME solution containing alpha-chymotrypsin and BSA selectively released the former protein, with chymotryptic activity occurring in the recovered protein. Possible mechanisms for the cosurfactant-mediated release of protein are discussed. Copyright 1998 John Wiley & Sons, Inc.
...
PMID:Expulsion of proteins from water-in-oil microemulsions by treatment with cosurfactant 1009 72

Gaseous CO2 was used as an antisolvent to induce the fractional precipitation of alkaline phosphatase, insulin, lysozyme, ribonuclease, trypsin, and their mixtures from dimethylsulfoxide (DMSO). Compressed CO2 was added continuously and isothermally to stationary DMSO solutions (gaseous antisolvent, GAS). Dissolution of CO2 was accompanied by a pronounced, pressure-dependent volumetric expansion of DMSO and a consequent reduction in solvent strength of DMSO towards dissolved proteins. View cell experiments were conducted to determine the pressures at which various proteins precipitate from DMSO. The solubility of each protein in CO2-expanded DMSO was different, illustrating the potential to separate and purify proteins using gaseous antisolvents. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE) was used to quantify the separation of lysozyme from ribonuclease, alkaline phosphatase from insulin, and trypsin from catalase. Lysozyme biological activity assays were also performed to determine the composition of precipitates from DMSO initially containing lysozyme and ribonuclease. SDS-PAGE characterizations suggest that the composition and purity of solid-phase precipitated from a solution containing multiple proteins may be accurately controlled through the antisolvent's pressure. Insulin, lysozyme, ribonuclease, and trypsin precipitates recovered substantial amounts of biological activity upon redissolution in aqueous media. Alkaline phosphatase, however, was irreversibly denaturated. Vapor-phase antisolvents, which are easily separated and recovered from proteins and liquid solvents upon depressurization, appear to be a reliable and effective means of selectively precipitating proteins.
...
PMID:Protein purification with vapor-phase carbon dioxide. 1009 36

Peroxisomes and the activities of their enzymes have been reported to be significantly reduced in various types of tumors including the colon carcinoma. Therefore, the present study was designed to investigate the gene expression of several peroxisomal proteins in human colon carcinoma and additionally those of the peroxisome proliferator activated receptor alpha (PPARalpha) and PEX5, a receptor protein involved in the import of most peroxisomal matrix proteins. Samples from adenocarcinomas and adjacent normal colon were analyzed by immunohistochemistry and western blotting. The mRNA content was assessed by a novel sensitive dot blot RNase protection assay and northern blotting. By immunohistochemistry, peroxisomes were distinctly visualized in normal colonocytes but were not detected in colon carcinoma cells. The protein levels of catalase (CAT), acyl-CoA oxidase as well as the 22 and 70 kDa peroxisomal membrane proteins (PMP22 and PMP70) were all significantly decreased in carcinomas. The corresponding mRNAs for CAT and PMP70, however, were unchanged. In contrast, the mRNA of PEX5 was significantly increased. The expression of PPARalpha was not altered in tumors, neither at protein nor mRNA levels. These observations show that the reduction of peroxisomes and their proteins in colon carcinoma is not due to a generalized reduction of transcription of their genes. It seems more likely that this phenomenon is regulated at a post-transcriptional or translational level. Alternatively, and more likely, an impairment of the biogenesis of the organelle could account for the paucity of peroxisomes in colon carcinoma.
...
PMID:Impairment of peroxisomal biogenesis in human colon carcinoma. 1035 77

We have cloned a 3.6-kb genomic DNA fragment from Pseudomonas aeruginosa harboring the rpoA, rplQ, katA, and bfrA genes. These loci are predicted to encode, respectively, (i) the alpha subunit of RNA polymerase; (ii) the L17 ribosomal protein; (iii) the major catalase, KatA; and (iv) one of two iron storage proteins called bacterioferritin A (BfrA; cytochrome b1 or b557). Our goal was to determine the contributions of KatA and BfrA to the resistance of P. aeruginosa to hydrogen peroxide (H2O2). When provided on a multicopy plasmid, the P. aeruginosa katA gene complemented a catalase-deficient strain of Escherichia coli. The katA gene was found to contain two translational start codons encoding a heteromultimer of approximately 160 to 170 kDa and having an apparent Km for H2O2 of 44.7 mM. Isogenic katA and bfrA mutants were hypersusceptible to H2O2, while a katA bfrA double mutant demonstrated the greatest sensitivity. The katA and katA bfrA mutants possessed no detectable catalase activity. Interestingly, a bfrA mutant expressed only approximately 47% the KatA activity of wild-type organisms, despite possessing wild-type katA transcription and translation. Plasmids harboring bfrA genes encoding BfrA altered at critical amino acids essential for ferroxidase activity could not restore wild-type catalase activity in the bfrA mutant. RNase protection assays revealed that katA and bfrA are on different transcripts, the levels of which are increased by both iron and H2O2. Mass spectrometry analysis of whole cells revealed no significant difference in total cellular iron levels in the bfrA, katA, and katA bfrA mutants relative to wild-type bacteria. Our results suggest that P. aeruginosa BfrA may be required as one source of iron for the heme prosthetic group of KatA and thus for protection against H2O2.
...
PMID:Bacterioferritin A modulates catalase A (KatA) activity and resistance to hydrogen peroxide in Pseudomonas aeruginosa. 1036 48

Mechanical overload may change cardiac structure through angiotensin II-dependent and angiotensin II-independent mechanisms. We investigated the effects of mechanical strain on the gene expression of tenascin-C, a prominent extracellular molecule in actively remodeling tissues, in neonatal rat cardiac myocytes. Mechanical strain induced tenascin-C mRNA (3.9 +/- 0.5-fold, p < 0.01, n = 13) and tenascin-C protein in an amplitude-dependent manner but did not induce secreted protein acidic and rich in cysteine nor fibronectin. RNase protection assay demonstrated that mechanical strain induced all three alternatively spliced isoforms of tenascin-C. An angiotensin II receptor type 1 antagonist inhibited mechanical induction of brain natriuretic peptide but not tenascin-C. Antioxidants such as N-acetyl-L-cysteine, catalase, and 1, 2-dihydroxy-benzene-3,5-disulfonate significantly inhibited induction of tenascin-C. Truncated tenascin-C promoter-reporter assays using dominant negative mutants of IkappaBalpha and IkappaB kinase beta and electrophoretic mobility shift assays indicated that mechanical strain increases tenascin-C gene transcription by activating nuclear factor-kappaB through reactive oxygen species. Our findings demonstrate that mechanical strain induces tenascin-C in cardiac myocytes through a nuclear factor-kappaB-dependent and angiotensin II-independent mechanism. These data also suggest that reactive oxygen species may participate in mechanically induced left ventricular remodeling.
...
PMID:Induction of tenascin-C in cardiac myocytes by mechanical deformation. Role of reactive oxygen species. 1041 1

Our previous studies have shown that exercise caused changes in the tissue activities of the antioxidant enzymes glutathione peroxidase, superoxide dismutase, and catalase in spontaneously hypertensive (SH) and Wistar-Kyoto (WKY) rats. To determine whether the changes observed were due to changes in mRNA levels of the enzymes, levels of tissue mRNA were determined by quantitative RNase protection assay. Comparisons of tissue enzyme activities and mRNA levels in sedentary and exercised animals showed that, in some cases (e.g., glutathione peroxidase in SH and WKY myocardium), parallel changes in enzyme activity and mRNA levels occurred, whereas in other cases (e.g., catalase in SH and WKY liver), nonparallel changes were found. Exercise of hypertensive rats altered antioxidant enzyme mRNA levels to those seen in normotensive animals in some, but not all, cases. The results suggest that transcriptional control over changes in exercise-related antioxidant enzyme activities is operative in some cases, although in other cases posttranscriptional regulatory mechanisms may exist.
...
PMID:Exercise modulates antioxidant enzyme gene expression in rat myocardium and liver. 1079 43

In this study, we have cloned the ankB gene, encoding an ankyrin-like protein in Pseudomonas aeruginosa. The ankB gene is composed of 549 bp encoding a protein of 183 amino acids that possesses four 33-amino-acid ankyrin repeats that are a hallmark of erythrocyte and brain ankyrins. The location of ankB is 57 bp downstream of katB, encoding a hydrogen peroxide-inducible catalase, KatB. Monomeric AnkB is a 19.4-kDa protein with a pI of 5.5 that possesses 22 primarily hydrophobic amino acids at residues 3 to 25, predicting an inner-membrane-spanning motif with the N terminus in the cytoplasm and the C terminus in the periplasm. Such an orientation in the cytoplasmic membrane and, ultimately, periplasmic space was confirmed using AnkB-BlaM and AnkB-PhoA protein fusions. Circular dichroism analysis of recombinant AnkB minus its signal peptide revealed a secondary structure that is approximately 65% alpha-helical. RNase protection and KatB- and AnkB-LacZ translational fusion analyses indicated that katB and ankB are part of a small operon whose transcription is induced dramatically by H(2)O(2), and controlled by the global transactivator OxyR. Interestingly, unlike the spherical nature of ankyrin-deficient erythrocytes, the cellular morphology of an ankB mutant was identical to that of wild-type bacteria, yet the mutant produced more membrane vesicles. The mutant also exhibited a fourfold reduction in KatB activity and increased sensitivity to H(2)O(2), phenotypes that could be complemented in trans by a plasmid constitutively expressing ankB. Our results suggest that AnkB may form an antioxidant scaffolding with KatB in the periplasm at the cytoplasmic membrane, thus providing a protective lattice work for optimal H(2)O(2) detoxification.
...
PMID:AnkB, a periplasmic ankyrin-like protein in Pseudomonas aeruginosa, is required for optimal catalase B (KatB) activity and resistance to hydrogen peroxide. 1091 88

Administration of aflatoxin B1 to rats (2 mg/kg intraperitoneally) caused significant increase in the activities of gamma-glutamyl transpeptidase, 5'-nucleotidase, acid phosphatase, acid ribonuclease as well as content of lipid peroxides in liver after six weeks. However, the activities of succinate dehydrogenase, glucose-6-phosphatase, catalase, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase and glutathione reductase in liver were decreased. The levels of glycogen and reduced glutathione were also decreased. There were significant elevations in the levels of serum transaminases, phosphatases (acid and alkaline), dehydrogenases (sorbitol, lactate and glutamate) and bilirubin following aflatoxin B1 administration. Picroliv (25 mg/kg/day orally for six weeks), an iridoid glycoside isolated from the roots and rhizomes of Picrorhiza kurroa, significantly prevented the biochemical changes induced by aflatoxin B1.
...
PMID:Biochemical changes induced in liver and serum of aflatoxin B1-treated male wistar rats: preventive effect of picroliv. 1116 62

We present liver mRNA levels of the two antioxidant enzymes catalase (CAT) and Mn-superoxide dismutase (SOD2) in four treatment groups of house mice assayed by RNase protection at 20 months of age. These groups were mice from four replicate selection and four replicate control lines from the sixteenth generation of selective breeding for high voluntary wheel running, housed with or without running wheels from age 3 weeks through 20 months. Exercising control females had induced CAT expression; SOD2 exhibited a similar pattern in females from two of the four control lines. Exercising male mice had induced CAT expression, but not SOD2 expression, irrespective of genetic background. We discuss these results with respect to both evolutionary (genetic) and training (exercise-induced) adaptations and explore predictions of these results in relation to the oxidative-damage theory of senescence.
...
PMID:Antioxidant gene expression in active and sedentary house mice (Mus domesticus) selected for high voluntary wheel-running behavior. 1219 16

Chromium (Cr) is fairly abundant in the earth's crust and ranks fourth among the 29 elements of biological importance. Besides natural sources, Cr enters biotic components of the ecosystem in various ways. Of other major industrial sources, tanning and chrome-plating industries are prominent sources. Cr(VI) form of chromium is highly reactive and influences both plants and animals. Due to Mn present in soil, Cr(III) is oxidized to Cr(VI) which remains in soil for a long time and can affect plant growth and development. Since maize is an important food and fodder plant for human beings and cattle, a study was conducted to investigate the effects of Cr on some metabolic activities of maize (Zea mays L. cv. Ganga 5). Chromium caused visible lesions of interveinal chlorosis. Young leaves showed vein clearing. Also, a papery appearance was observed in leaves. Margins of leaves were curled and the leaves appeared pale at greater Cr exposure. Concentrations of both chlorophyll a and b were reduced by exposure to Cr, the activities of ribonuclease and phenyl phosphatase were greater while the activity of iron-porphyrin enzyme catalase was less and the activity of amylase was also much less in plants exposed to Cr. Chromium also caused retardation of soluble protein. Accumulation of Cr in roots was much at all the levels of chromium supply. Exposure to Cr resulted in reduction in grain production and quality.
...
PMID:Phytotoxic lesions of chromium in maize. 1258 57


<< Previous 1 2 3 4 5 Next >>

---