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:3.1.26.9 (ribonuclease)
6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nuclear bodies about 250 nm in diameter, and with a strong affinity for uranium and acriflavine, appear in the nuclei of maturing egg cells of Pteridium. Many enter well-defined evaginations of the nucleus. The nuclear bodies are almost wholly digested by Pronase, but are resistant to ribonuclease and deoxyribonuclease. Radioactive labelling gives no evidence of the presence of nucleic acids, but X-ray microprobe analysis indicates phosphorus. It is concluded that the bodies consist entirely of acidic protein, possibly phosphorylated. This protein may be a structural component of the nucleus, temporarily displaced and aggregated as a consequence of the fine dispersal of the chromatin.
...
PMID:Nuclear bodies in the maturing egg cell of a fern, Pteridium aquilinum. 668 23

High-performance liquid chromatography of carbohydrate materials on graphitized carbon columns (GCC) has some advantages over other types of chromatography. Oligosaccharides and glycopeptides with few amino acids are barely retained on reversed-phase columns even under high salt or low pH conditions, but can be retained effectively on a graphitized carbon column. Moreover, elution of GCC requires concentrations of organic solvents lower than that required for normal-phase columns. The usefulness of graphitized carbon columns is exemplified by the following results: (i) Man9GlcNAc2 with only Asn or Asn-Phe (derived from soybean agglutinin) was not retained by a C18 reversed-phase column, but could be separated on a GCC with a gradient of 10-45% CH3CN in 30 min. (ii) Ribonuclease B glycopeptides obtained by Pronase digestion could be separated on GCC with a gradient of 10-30% CH3CN, but they were not retained on a C18 reversed-phase column even with water as eluent. (iii) Oligosaccharides released from ribonuclease B by endo-beta-N-acetylglucosaminidase were separated from each other and peptides on GCC with a linear gradient of 10 mM NH4OH to 10 mM NH4OH-12.5% CH3CN in 50 min at 70 degrees C. Silica-based columns do not allow such an alkaline eluent. (iv) Chito-oligosaccharides (DP 1-9) are well separated within 40 min on GCC with a gradient (10 mM NH4OH-10 mM NH4OH with 25% CH3CN) at 50 degrees C. Chito-oligosaccharides could not be separated by high-performance anion exchange columns such as Carbopac PA-1.
...
PMID:High-performance liquid chromatography of glycopeptides and oligosaccharides on graphitized carbon columns. 808 79

An approach for the characterization of glycosylation sites and oligosaccharide heterogeneity in glycoproteins based on a combination of nonspecific proteolysis, deglycosylation, and matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FT MS) is described. Glycoproteins were digested with Pronase yielding primarily glycopeptides and amino acids. Nonglycosylated peptide fragments were susceptible to complete Pronase digestion to their constituent amino acids. Steric hindrance prohibited the digestion of the peptide moiety attached to the glycan. Glycopeptides were desalted and concentrated using solid-phase extraction and analyzed by MALDI MS. The oligosaccharides were also analyzed by MALDI MS after releasing the glycans from glycoproteins using PNGase F. The peptide moiety of the glycopeptides was identified by subtracting the masses of the glycans derived from PNGase F treatment from the masses of the glycopeptides. The experimental strategy was validated using glycoproteins with known oligosaccharide structures, ribonuclease B and chicken ovalbumin. This procedure was then used to determine the N-glycosylation sites and site heterogeneity of a glycoprotein whose glycosylation pattern was unknown, namely, the Xenopus laevis egg cortical granule lectin. This procedure is useful for determining protein site heterogeneity and structural heterogeneities of the oligosaccharide moiety of glycoproteins.
...
PMID:Determination of N-glycosylation sites and site heterogeneity in glycoproteins. 1471 Aug 47

A new method for the mass spectrometric characterization of site-specific protein glycosylation is presented. Glycoprotein samples were subjected to unspecific proteolysis by Pronase, resulting in glycopeptides with peptide moieties of mostly two to eight amino acids. Resulting (glyco-)peptide samples were resolved by nanoscale normal-phase liquid chromatography (LC)-online mass spectrometry (MS). Retention depended on the size of the glycan chain and allowed the separation of identical peptide moieties containing different N-glycan structures. Glycopeptides were analyzed in an ion trap instrument performing repetitive ion isolation/fragmentation cycles. While the MS/MS spectra were dominated by fragmentations of glycosidic linkages, MS(3) spectra exhibited cleavages of the peptide backbone and provided information on the peptide sequence and glycan attachment site. When applied to the model glycoproteins ribonuclease B and horseradish peroxidase (HRP), the method provided detailed insights into protein glycosylation and revealed some new features of site-specific glycosylation of HRP. Application of the method to Dolichos biflorus lectin, which has hitherto not been studied with respect to its glycosylation, identified two glycans attached alternatively to its single glycosylation site. Thus, the presented, unique combination of Pronase digestion of glycoproteins, normal-phase nano-LC, and multistage MS provides a method for the facile characterization of site-specific protein glycosylation.
...
PMID:Protein glycosylation analyzed by normal-phase nano-liquid chromatography--mass spectrometry of glycopeptides. 1567 58

Syringacin 4-A, a bacteriocin produced by Pseudomonas syrinagae 4-A, was obtained by induction with ultraviolet irradiation or mitomycin C. Approximately 1,000-fold purification of the bacteriocin was achieved by manganous chloride precipitation, differential centrifugation, and chromatography on hydroxyapatite columns. The purified syngacin was homogeneous on hydroxyapatite columns and sucrose density gradients; it also sedimented as a single entity in the analytical ultracentrifuge. The buoyant density of purified syringacin in cesium chloride was 1.294 g/ml. The sedimentation coefficient was calculated as 120S, and the diffusion coefficient was 6.49 x 10(-8) cm(2)/s. The molecular weight was calculated as 1.6 x 10(7) from physical data and 1.7 x 10(7) from biological data. The syringacin was composed of about 88.4% protein, 8.5% arabinose, 2.2% galacturonic acid, and 0.7% glucosamine. Amino acid analysis indicated a predominance of leucine (12.1%), aspartic acid (12.2%), and glutamic acid (12.7%). The ultraviolet spectrum showed a maximum absorbance peak at 276 nm. The syringacin was heat and alcohol sensitive, but resistant to trypsin, chymotrypsin, carboxypeptidase, Pronase, protease, lysozyme, steapsin, deoxyribonuclease, and ribonuclease. Maximum pH stability was between 5 and 8. Crude bacteriocin was stable at room temperature for at least a year, and purified material was stable for at least 3 months at 4 C.
...
PMID:Purification and characterization of syringacin 4-A, a bacteriocin from pseudomonas syringae 4-A. 1582 74

Protective immunity was elicited by immunization of mice with ribosomal preparations from yeast cells of Histoplasma capsulatum. Ribosomes from disrupted cells were isolated by differential centrifugation using sodium dodecyl sulfate. These preparations contained 55% protein and 45% ribonucleic acid and sedimented as a single peak with a sedimentation coefficient of 77S on sucrose density gradient analysis. Mice immunized subcutaneously with ribosomes, with or without adjuvant, were challenged intravenously with 8 x 10(6) yeast cells of H. capsulatum. Significant protection was induced by ribosomes and was greatly enhanced by adjuvants. Protection measured by 30-day survival compared favorably with the immunoprotection assessed by absence of lung lesions and negative spleen cultures. Treatment of ribosomes with ribonuclease before immunization reduced protection by 85%, whereas trypsin and Pronase reduced the protection by 50 to 55%. These findings indicate that both intact ribosomal ribonucleic acid and protein are necessary for maximal immunogenicity of Histoplasma ribosomes.
...
PMID:Immunogenicity of Ribosomal Preparations from Yeast Cells of Histoplasma capsulatum. 1655 95

A simple and rapid "one-pot" methylation method to esterify sialic acids and construct a permanent charge was developed for N-linked glycan analysis, which combined complete nonspecific proteolytic digestion and methylation. A mixture of Asn-glycans prepared from Pronase E digestion of the glycoprotein was passed through a cation-exchange column to convert carboxylic acids to the Na+ form before being methylated with methyl iodide. Derivatives could be easily purified with a hydrophilic affinity chromatography cartridge. Mass spectrometry analysis was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and MALDI-TOF/TOF. The mass spectrometric data indicated that carboxylic acids were methylated in addition to the formation of a quaternary ammonium in the amino group of asparagine residues. Three model glycoproteins, including ribonuclease B, ovalbumin, and transferrin, were employed to demonstrate the merits of this technique. Results showed that the stabilization of sialic acid was achieved in addition to the formation of a permanent charge. Compared to the analysis of underivatized N-glycans, detection sensitivity improved approximately 10-fold. The new technique was further evaluated with glycan profiling of serum transferrin and proved to be a sensitive method for the characterizing protein glycosylation.
...
PMID:"One-pot" methylation in glycomics application: esterification of sialic acids and permanent charge construction. 1741 Oct 71

The nature of the 5' terminus of tobacco vein mottling virus (TVMV) RNA, a member of the potyvirus group, was investigated. Digestion of viral RNA with ribonuclease led to the appearance of a new polypeptide band of apparent molecular weight 24,000 (24 kDa) after electrophoresis on denaturing polyacrylamide gels. Viral RNA was subjected to radioiodination with the protein-specific Bolton-Hunter reagent. Radioactivity cosedimented on sucrose gradients with intact TVMV RNA. Treatment of the 125I-labeled product with the proteinase Pronase resulted in substantial loss of trichloroacetic acid-precipitable radioactivity. A radioactive species of 24 kDa was released when the(125)I-labeled product was subjected to ribonuclease digestion. To localize the point of attachment, the 125I-labeled TVMV RNA was partially hydrolyzed and used as a hybridization probe against four previously described recombinant plasmids containing TVMV cDNA and a fifth plasmid containing additional 5'-terminal sequences. Hybridization was strongest to plasmids containing the most 5'-terminal sequences. Antisera against the five known proteins encoded by TVMV RNA failed to precipitate significant amounts of the new protein. This genome-linked viral protein (VPg) thus constitutes the sixth polypeptide to be associated with TVMV. It also has the largest apparent molecular weight of any RNA-linked VPg reported to date.
...
PMID:Identification of a protein covalently linked to the 5' terminus of tobacco vein mottling virus RNA. 1863 44

From saline extracts of Phytolacca esculenta (shoriku) roots, two phytomitogenes were isolated by salting out with (NH4),SO4 and chromatography on DEAE-cellulose and Sephadex G-100 columns. Both fractions were homogeneous on disc electrophoresis and on immunoelectrophoresis. One of these (Fraction E-2) was shown to be similar to pokeweed mitogen in respect to mol. wt (32,000) and amino acid composition. The other (Fraction E-3) was a protein of 18,000 mol. wt. Both fractions had similar biological activities to pokeweed mitogen in their ability to stimulate pig blood lymphocytes in vitro to incorporate tritiated thymidine, and to induce blastoid transformation. Both fractions contained an unusually large amount of cystine, i.e., 18 half-cystine residues % for Fraction E-2 and 22 residues % for Fraction E-3. Although these mitogens were resistant to deproteinizing procedures such as perchloric acid treatment and Sevag's procedure, the DNA synthesis-stimulating activity was inactivated by digestion with Pronase E and Nagarse, but resistant to trypsin, chymotrypsin, deoxyribonuclease, ribonuclease, lysozyme and neuraminidase. The activity was stable at acidic and neutral pH (4-7) but unstable at alkaline pH. The activity at pH 7.3 was stabilized by the addition of Ca2+ or Mg2+. On the addition of more than 2 mM of Ca2+, precipitation of mitogen occurred. From the above results the molecular basis of the mitogenic activity of shoriku mitogen is discussed.
...
PMID:Isolation and characterization of pokeweed mitogen-like phytomitogens from Shoriku, Phytolacca esculenta. 1999 19

With Boc-Asn-GlcNAc as a basic structure, four permanently positively charged kinds of new acceptors (GP-Boc-Asn-GlcNAc, GT-Boc-Asn-GlcNAc, HMP-Boc-Asn-GlcNAc, MPDPZ-Boc-Asn-GlcNAc) and five kinds of similar structure acceptors (2-PA-Boc-Asn-GlcNAc, 3-PA-Boc-Asn-GlcNAc, 4-PA-Boc-Asn-GlcNAc, HP-Boc-Asn-GlcNAc, PDPZ-Boc-Asn-GlcNAc) were synthesized as acceptors for the resolution of oligosaccharides in glycopeptides. The synthesized acceptors enzymatically reacted with Disialo-Asn (donor) in the presence of Endo-M. The reaction yields of each transglycosylation product were not obvious, because we do not have all the authentic Disialo-Asn-Boc-acceptors. Therefore, we used the peak area of the transglycosylation product detected by mass spectrometry and evaluated the utility of each acceptor. Among the Boc-Asn-GlcNAc acceptors, the positively charged MPDPZ derivative peak area was the highest, MPDPZ-Boc-Asn-GlcNAc with a positively charged structure showed about a 2.2 times greater sensitivity of the transglycosylation product compared to the conventional fluorescence acceptor DBD-PZ-Boc-Asn-GlcNAc. As a result, the MPDPZ-Boc-Asn-GlcNAc acceptor was suitable for the transglycosylation reaction with Endo-M. The development of a qualitative determination method for the N-linked oligosaccharides in glycoproteins was attempted by combination of the transglycosylation reaction and semi-micro high-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (HPLC/ESI-QTOF-MS/MS). The asparaginyl-oligosaccharides in glycoproteins, liberated by treatment with Pronase E, were separated, purified and labeled with positively charged MPDPZ. The resulting derivatives were separated by a semi-micro HPLC system. The eluted N-linked oligosaccharide derivatives were then introduced into a QTOF-MS instrument and sensitively detected in the ESI(+) mode. Various fragment ions based on the carbohydrate units appeared in the MS/MS spectra. Among the peaks, m/z 782.37 corresponding to MPDPZ-Boc-Asn-GlcNAc is the most important one for identifying the asparaginyl-oligosaccharides. Disialo-Asn-Boc-MPDPZ was easily identified by the selected-ion chromatogram at m/z 782.37 by MS/MS detection. Therefore, the identification of N-linked oligosaccharides in glycoproteins seems to be possible by the proposed semi-micro HPLC separations followed by the QTOF-MS/MS detection. Furthermore, several oligosaccharides in ovalbumin and ribonuclease B were successfully identified by the proposed procedure.
...
PMID:Development of novel active acceptors possessing a positively charged structure for the transglycosylation reaction with Endo-M and their application to oligosaccharide analysis. 2191 70


<< Previous 1 2 3 4 5 Next >>

---