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)

From experiments with glycoproteins containing the glycopeptide linkages, arabinose-O-hydroxyproline and galactose-O-serine (plant cell wall glycopeptides), N-acetylgalactosamine-O-serine/threonine (pig submaxillary mucin), and N-acetyl-glucosamine-N-asparagine (fetuin), it is apparent that anhydrous liquid HF, a reagent commonly used by snythetic peptide chemists for the complete removal of protecting groups from synthetic peptides, cleaves the O-glycosidic linkages of neutral sugars in 1 hr at 0 degrees C, and the O-glycosidic linkages of amino sugars in 3 hr at 23 degrees C. The N-glycosidic linkage of N-acetylglucosamine to asparagine is not cleaved under any conditions that have been tested. Sodium dodecyl sulfate gel electrophoresis of bovine serum albumin treated in HF does not show any degradation of peptide bonds. Some relatively stable enzymes (lysozyme and RNase) have been shown by others to retain most of their enzymic activity after short treatment (1 hr at 0 degrees C) in HF. With the specificity of HF at 0 degrees C for neutral sugars it should be possible to generate di- or trisaccharides in high yield from polysaccharides containing both neutral and amino sugars with neutral sugars as the reducing termini.
...
PMID:A new approach to the structural determination of glycoproteins and polysaccharides: anhydrous HF solvolysis. 7 2

Bacteriocin-like substances were commonly produced by slow-growing Rhizobium japonicum and cowpea rhizobia on an L-arabinose medium. Antagonism between strains of R. japonicum was not detected in vitro; however, such strains were often sensitive to some bacteriocins produced by cowpea rhizobia. Inhibitory zones (2 to 8 mm from colony margins), produced by 58 of 66 R. japonicum test strains, were reproducibly detected with Corynebacterium nebraskense as an indicator. Quantitative production was not related to symbiotic properties of effective strains, since nine noninfective strains and one ineffective strain produced bacteriocin. Eight R. japonicum strains that did not produce bacteriocin nevertheless formed effective nodules on soybeans. R. japonicum strains that produced bacteriocin in vitro had no antagonistic effect on nonproducer strains during soybean nodulation. Under controlled conditions, a nonproducer (3I1b135) predominated over a bacteriocin producer (3I1b6) when inoculated at 1:1 and 1:9 ratios. Depending on the particular ratio, up to 38% of the total nodules formed were infected with mixed combinations. The bacteriocin(s) had a restricted host range and antibiotic-like properties which included the ability to be dialyzed and resistance to heat (75 to 80 degrees C, 30 min), Pronase, proteinase K, trypsin, ribonuclease, and deoxyribonuclease. R. japonicum strains representing genetic, serological, cultural, and geographic diversity were differentiated into three groups on the basis of bacteriocin production.
...
PMID:Bacteriocin-like substances produced by Rhizobium japonicum and other slow-growing rhizobia. 57 16

One hundred twenty-seven isolates of Aeromonas comprising the three currently recognizable species (A. hydrophila, A. sobria, and A. caviae) were evaluated for biochemical and exoenzymatic properties. Aeromonas species were generally (greater than 90%) characterized as gram-negative fermentative rods that were oxidase-, catalase-, and beta-galactosidase-positive, produced arginine dihydrolase, and failed to decarboxylate ornithine. More than 95% of all isolates tested failed to grow on 6.5% salt or thiosulfate-citrate bile salts agar and were resistant to the vibriostatic agent 0/129. Most Aeromonas species produced acid from hexoses while failing to ferment alcoholic sugars or trisaccharides. In exoenzymatic studies, Aeromonas species were uniformly found to produce several exoenzymes, including amylase, DNase, RNase, esterase, lipase, gelatinase, protease, fibrinolysin, and chitinase. Within the genus, a number of biochemical and enzymatic properties were found to be associated with one or more of the taxonomically recognizable species. These properties included glycoside utilization, Heiberg grouping based upon fermentation of arabinose, sucrose, and mannose, and the elaboration of several extracellular enzymes (elastase, hemolysin, lecithinase, phosphatase). In addition, phenotypic markers previously associated with enterotoxigenic Aeromonas isolates were almost exclusively found among A. hydrophila and A. sobria species, suggesting that these species are the major enteric pathogens.
...
PMID:Biochemical and exoenzymatic properties of Aeromonas species. 388 8

Mannose-specific binding sites for horseradish peroxidase (HRP) were studied in fixed sections of various tissues by a method reported previously. Liver sinusoidal cells, mast cells of lymph nodes, and alveolar macrophages of the lung and skin fibroblasts were main cell types showing mannose-specific binding of HRP. Macrophages, fibroblasts, and mast cells in the connective tissue of other organs also showed the reaction. However, macrophages of the spleen, and cultured 3T3 cells and L-cells did not give the reaction. The specificities of the binding reaction were studied by determining the approximate concentrations of competing sugars that suppressed the specific binding of HRP. It was found that the endogenous lectins in macrophages, fibroblasts, mast cells, and liver sinusoidal cells showed similar specificities toward various carbohydrates. D-Mannose and L-fucose had the highest affinity toward the lectins (competing ability for the binding of HRP). D-Mannose-6-phosphate, N-acetyl-D-glucosamine, D-glucose, D-ribose, and D-arabinose showed intermediate affinity, whereas D-xylose and D-galactose showed low affinity. Polymerized mannose in mannan and glycoproteins rich in mannose groups (invertase and ribonuclease B) showed much higher affinity to the binding sites than free mannose.
...
PMID:Mannose-specific binding sites for horseradish peroxidase in various cells of the rat. 683 41

Ribonuclease B has become a paradigm as a simple example of an N-linked glycoprotein. We have found that certain affinity-purified preparations of this enzyme demonstrated a pronounced tendency to lose activity if stored as dilute aqueous solutions. Such inactivation is accelerated by the presence of NaCl, but can be counteracted by inclusion of high (1 mol/l) concentrations of xylose. Enzyme activity cannot be restored by addition of xylose after storage of the enzyme. In marked contrast to alpha-methyl-mannoside, xylose does not prevent ribonuclease B from binding to concanavalin A and so may be used to stabilize the enzyme during purification by lectin affinity chromatography.
...
PMID:Stabilization of ribonuclease B activity by concentrated xylose solutions. 785

Glycation and oxidation reactions contribute to protein modification in aging and diabetes. Formation of dicarbonyl sugars during autoxidation of glucose is the hypothetical first step in the autoxidative glycosylation and subsequent browning of proteins by glucose [Wolff, S. P., & Dean, R. T. (1987) Biochem. J. 245, 243-250]. In order to identify the dicarbonyl sugar(s) formed during autoxidation of glucose under physiological conditions, glucose was incubated in phosphate buffer (pH 7.4) at 37 degrees C under air (oxidative conditions) or nitrogen with transition metal chelators (antioxidative conditions). Dicarbonyl compounds were analyzed spectrophotometrically and by HPLC after reaction with Girard-T reagent. Carbohydrates were analyzed by gas chromatography-mass spectrometry. Both dicarbonyl sugar and arabinose concentrations increased with time and glucose concentration in incubations conducted under oxidative conditions; only trace amounts of these products were detected in glucose incubated under antioxidative conditions. HPLC analysis of adducts formed with Girard-T reagent indicated that glyoxal was the only alpha-dicarbonyl sugar formed on autoxidation of glucose. Glyoxal and arabinose accounted for > or = 50% of the glucose lost during a 21 day incubation. Neither glucosone nor its degradation product, ribulose, was detectable. Reaction of glyoxal with RNase yielded the glycoxidation product, N epsilon-(carboxymethyl)lysine, while arabinose is a source of pentosidine. Our results implicate glyoxal and arabinose as intermediates in the browning and crosslinking of proteins by glucose under oxidative conditions. They also provide a mechanism by which antioxidants and dicarbonyl trapping reagents, such as aminoguanidine, limit glycoxidation reactions and support further evaluation of these types of compounds for inhibition of chemical modification and crosslinking of proteins during aging and diabetes.
...
PMID:Mechanism of autoxidative glycosylation: identification of glyoxal and arabinose as intermediates in the autoxidative modification of proteins by glucose. 789 66

A base non-specific and acid RNase was isolated from cellular slime mold (Dictyostelium discoideum) cells in a homogeneous state (about 2.4 kDa) by SDS-polyacrylamide gel electrophoresis. The RNase (RNase DdI) has a pH optimum of 5.0. The amino acid sequence of RNase DdI was determined by a combination of protein chemistry, a search of Data base, Dicty cDB and further sequence analysis of cDNA from the same bank. RNase DdI consists of 198 amino acid residues, and about 13.3, 0.9, 1.2, 3.3, and 1.0 residues of mannose, xylose, glucose, GlcNAc, and GalNAc, respectively. RNase DdI has two characteristic conserved segments of the RNase T2 family, and thus belongs to the RNase T2 family. Considering the fact that most of the RNase activity of D. discoideum is present in the lysosomal fraction [Wiener and Ashworth (1970) Biochem. J. 118, 505-512], it was concluded that the lysosomal RNase in D. discoideum is a member of the RNase T2 family. The amino acid sequence of RNase DdI is highly homologous with that of Physarum polycephalum RNase (RNase Phyb), and its amino acid sequence seems to be similar to those of plant/animal type RNases, rather than fungal RNases. The location of RNase DdI in the phylogenetic tree of the RNase T2 family was estimated.
...
PMID:Characterization and primary structure of a base non-specific and acid ribonuclease from Dictyostelium discoideum. 975 33

In plants, the pollen coat covers the exine wall of the pollen and is the outermost layer that makes the initial contact with the stigma surface during sexual reproduction. Little is known about the constituents of the pollen coat, especially in wind-pollinated species. The pollen coat was extracted with diethyl ether from the pollen of maize (Zea mays L.), and a predominant protein of 35 kDa was identified. On the basis of the N-terminal sequence of this protein, a cDNA clone of the Xyl gene was obtained by reverse transcriptase-polymerase chain reaction. The deduced amino acid sequence of the 35-kDa protein shared similarities with the sequences of many microbial xylanases and a barley aleurone-layer xylanase. The 35-kDa protein in the pollen-coat extract was purified to homogeneity by fast protein liquid chromatography and determined to be an acidic endoxylanase that was most active on oat spelt xylan. Northern and in situ hybridization showed that Xyl was specifically expressed in the tapetum of the anther after the tetrad microspores had become individual microspores. Southern hybridization and gene-copy reconstruction studies showed only one copy of the Xyl gene per haploid genome. Analyses of the genomic DNA sequence of Xyl and RNase protection studies with the transcript revealed many regulatory motifs at the promoter region and an intron at the 5' leader region of the transcript. The Xyl transcript had a 562-nucleotide (nt) 5' leader, a 54-nt sequence encoding a putative signal peptide, a 933-nt coding sequence, and a 420-nt 3'-untranslated sequence. The unusually long 5' leader had an open reading frame encoding a putative 175-residue protein whose sequence was most similar to that of a microbial arabinosidase. The maize xylanase is the first enzyme documented to be present in the pollen coat. Its possible role in the hydrolysis of the maize type II primary cell wall (having xylose, glucose, and arabinose as the major moieties) of the tapetum cells and the stigma surface is discussed.
...
PMID:The predominant protein on the surface of maize pollen is an endoxylanase synthesized by a tapetum mRNA with a long 5' leader. 1042 75

S-RNases encoded by the S-locus of rosaceous and solanaceous plants discriminate between the S-alleles of pollen in gametophytic self-incompatibility reactions, but it is not clear how. We report the structures of N-glycans attached to each of the N-glycosylation sites of seven S-RNases in Pyrus pyrifolia of the Rosaceae. The structures were identified by chromatographic analysis of pyridylaminated sugar chains prepared from S4-RNase and by liquid chromatography/electrospray ionization-mass spectrometric analysis of the protease digests of reduced and S-carboxymethylated S-RNases. S4-RNase carries various types of sugar chains, including plant-specific ones with beta1-->2-linked xylose and alpha1-->3-linked fucose residues. More than 70% of the total N-glycans of S4-RNase are, however, an N-acetylglucosamine or a chitobiose (GlcNAcbeta1-->4GlcNAc), which has not been found naturally. The N-acetylglucosamine and chitobiose are mainly present at the N-glycosylation sites within the putative recognition sites of the S-RNase, suggesting that these sugar chains may interact with pollen S-product(s).
...
PMID:Presence of asparagine-linked N-acetylglucosamine and chitobiose in Pyrus pyrifolia S-RNases associated with gametophytic self-incompatibility. 1046 25

Oligonucleotide analogues comprised of 2'-deoxy-2'-fluoro-beta-D-arabinose units joined via P3'-N5' phosphoramidate linkages (2'F-ANA(5'N)) were prepared for the first time. Among the compounds prepared were a series of 2'OMe-RNA-[GAP]-2'OMe-RNA 'chimeras', whereby the "GAP" consisted of DNA, DNA(5'N), 2'F-ANA or 2'F-ANA(5'N) segments. The chimeras with the 2'F-ANA and DNA gaps exhibited the highest affinity towards a complementary RNA target, followed by the 5'-amino derivatives, i.e., 2'F-ANA > DNA > 2'F-ANA(5'N) > DNA(5'N). Importantly, hybrids between these chimeras and target RNA were all substrates of both human RNase HII and E. coli RNase HI. In terms of efficiency of the chimera in recruiting the bacterial enzyme, the following order was observed: gap DNA > 2'F-ANA > 2'F-ANA(5'N) > DNA(5'N). The corresponding relative rates observed with the human enzyme were: gap DNA > 2'F-ANA(5'N) > 2'F-ANA > DNA(5'N).
...
PMID:Synthesis and properties of oligonucleotide chimeras containing 5'-amino-2'-deoxy-2'-fluoroarabinonucleosides. 1456 12


1 2 Next >>

---