Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete amino acid sequence of ribonuclease N1 (RNase N1), a guanine-specific ribonuclease from a fungus, Neurospora crassa, was determined by conventional protein sequencing, using peptide fragments obtained by tryptic digestion of cyanogen bromide-treated RNase N1 and by Staphylococcus aureus V8 protease digestion of heat-denatured RNase N1. The results showed that the protein is composed of a single polypeptide chain of 104 amino acid residues cross-linked by two disulfide bonds and has a molecular weight of 11,174: (sequence; see text) (Disulfide bonds: C2-C10, C6-C103) The amino acid sequence was homologous with those of RNase T1 (65% identity) and related microbial RNases.
J Biochem 1988 Sep
PMID:The amino acid sequence of ribonuclease N1, a guanine-specific ribonuclease from the fungus Neurospora crassa. 297 30

Sodium bisulphite modification of foot-and-mouth disease virus (FMDV) RNA in solution indicates that the majority of the poly(C) tract in the RNA is single-stranded in concordance with previous results with encephalomyocarditis virus RNA. The reaction kinetics are biphasic; 60% of the cytidylic acid in the poly(C) tract reacts like synthetic poly(C), and the remainder with the kinetics of the cytidylic acid in the rest of the RNA. The reactivity of the poly(C) tract with poly(I) indicates that it is looped out and exposed in the RNA. The deamination reaction has also been used to investigate the structure of the replicative form (RF) and replicative intermediate (RI) isolated from infected cells. Analysis by gel electrophoresis of the long RNase A- and T1-resistant oligonucleotides of RI suggests that it has five single-stranded poly(C) tracts to every one which is base-paired. Bisulphite reactivity of the poly(C) tract and gel electrophoresis of the ribonuclease-resistant oligonucleotides of RF indicate that the poly(C) is base-paired to a poly(G) tract in this molecule. The presence of a poly(G) tract in RF and RI provides unequivocal evidence that the poly(C) is replicated via poly(G) in the negative strand.
J Gen Virol 1985 Sep
PMID:Analysis of the secondary structure of the poly(C) tract in foot-and-mouth disease virus RNAs. 299 83

We used in situ hybridization to look for picornavirus ribonucleic acid (RNA) sequences in frozen sections of central nervous system (CNS) tissue of amyotrophic lateral sclerosis (ALS) and control patients. Using reconstruction experiments, we concluded that 30 copies of viral RNA per cell could be detected with the assay. RNA which hybridized to DNAs complementary (cDNAs) to both poliovirus and Theiler's virus was found at several levels in the CNS of 2 patients, 1 ALS patient, and 1 control. In transverse sections of the spinal cord, these sequences predominated in cells of the anterior horns. We assessed the specificity of hybridization by several criteria: no hybridization was observed with heterologous visna virus cDNA probes; hybridization was abolished by pretreatment of the sections with ribonuclease; chemography artifacts were ruled out; and the results were reproduced in three independent experiments. We concluded that RNA molecules, possibly belonging to a picornavirus having sequences in common with poliovirus and Theiler's virus, were present in the CNS of these 2 patients. On the other hand, 14 cases of classic ALS, 2 cases of Guamanian parkinsonian dementia, and 5 controls had negative results. However, the presence of picornavirus sequences in our series could be underestimated because in many cases autolysis times were 10 hours or longer.
Ann Neurol 1985 Sep
PMID:Detection of picornavirus sequences in nervous tissue of amyotrophic lateral sclerosis and control patients. 299 16

The diagnostical relevance of the low-molecular proteins ribonuclease, beta 2-microglobulin and lysozyme in serum and urine to detect a reduced glomerular filtration rate was examined in 52 patients with chronic renal diseases. The radioisotope clearance using 99mTc-DTPA was the base reference; the reference values of the low-molecular proteins were estimated in a control group. Ribonuclease was increased above the upper borderline value, if the glomerular filtration rate was lower than 1.24 ml s-1. Creatinine, beta 2-microglobulin and lysozyme remain yet in part in the normal range. The estimation of the ribonuclease in serum is suitable to detect an impaired glomerular filtration rate if the creatinine value is still not increased. Thereby, the diagnostics in renal diseases may be improved in the creatinine-blind area.
Z Urol Nephrol 1988 Sep
PMID:[The low molecular weight proteins ribonuclease, beta 2 microglobulin and lysozyme in the serum and urine of patients with chronic kidney diseases]. 307 Oct 37

A new method is described for locating the specific sites of attachment of Asn-linked carbohydrates in glycoproteins. The molecular weights of peptides released from the glycoprotein with proteases of known specificity are determined by fast atom bombardment mass spectrometry and fitted to the known or DNA-derived sequence. Oligosaccharides attached to Asn are released either before or after proteolysis with a glycosidase, usually peptide: N-glycosidase F, an enzyme that cleaves the beta-aspartylglycosylamine linkage of all known types of Asn-linked sugars and converts the attachment-site Asn to Asp. New peaks appearing in the mass spectra after treatment with glycosidase correspond to formerly glycosylated sites. Conversely, signals which disappear after glycosidase treatment correspond to glycopeptides. The differences in mass between these sets of signals define the composition of the carbohydrate at the given site in terms of deoxyhexose, hexose, N-acetylhexosamine, and sialic acid content. The extent of glycosylation at a given site can be estimated from the ratio of the peak heights corresponding to the Asn- vs Asp-containing peptides which differ by 1 Da in mass. This rapid and sensitive (low nmol) technique is illustrated here for ribonuclease B and for tissue plasminogen activator, a multiply glycosylated glycoprotein.
Anal Biochem 1986 Sep
PMID:Carbohydrate mapping by mass spectrometry: a novel method for identifying attachment sites of Asn-linked sugars in glycoproteins. 309 66

By drop dialysis with membrane filters of 25 or 50 nm average pore size, salt concentrations are reduced to 15% within 25 min. During this time only 10% of ribonuclease with a Mr 13,500 will diffuse in and through the membrane. However, in the presence of 1 M NaCl about 25% of the enzyme is lost. The difference in the rate of salt removal and enzyme loss is caused by the difference in diffusion constants. Therefore with enzymes of higher molecular weights, less protein will be lost, as is shown with beta-galactose dehydrogenase. This enzyme with Mr 64,000 is lost at a lower rate than ribonuclease. The net charge of a protein apparently does not influence the rate with which it diffuses through the membrane. The time course of salt and protein exchange was studied to provide data for estimating the optimal conditions for the required reduction in salt concentration. To prepare small protein samples for electrophoresis or other analytical methods, which require low salt concentrations or a buffer change, drop dialysis is a fast and effective method with tolerable loss of protein.
Anal Biochem 1988 Sep
PMID:Drop dialysis: time course of salt and protein exchange. 314 1

The muscle wasting which occurs in animals bearing a transplantable tumour is accompanied by a decrease in the level of protein synthesis and a loss in RNA. This paper examines the behaviour of RNA polymerases I and II (EC 2.7.7.6) in nuclei isolated from skeletal muscle of rats bearing a Walker 256 carcinoma. Marked decreases were observed in template-engaged RNA polymerase I and II activities and in free RNA polymerase I activity. Free RNA polymerase II activity was unaltered. When assays were carried out at high (NH4)2SO4 concentration or in the presence of heparin the diminished RNA polymerase I activity was still apparent, but heparin and high ionic strength overcame the inhibition of RNA polymerase II. Loss of RNA polymerase I activity was associated with a decrease in the number of template-engaged enzyme molecules and in the polynucleotide elongation rate. The number of template-engaged RNA polymerase II molecules was unaltered by tumour growth, but the polynucleotide elongation rate was significantly reduced. No evidence was obtained for any alteration in ribonuclease activity in nuclei or whole muscles of tumour-bearing rats. These results demonstrate an effect of the tumor on transcription in skeletal muscle of its host.
Biochim Biophys Acta 1988 Sep 07
PMID:Response of skeletal muscle RNA polymerases I and II to tumour growth. 316 55

Retinoblastoma (RB) is a malignant tumor of developing retina that arises when abnormalities resulting in loss of function affect both alleles of the gene at the retinoblastoma locus (RB1) on chromosome 13q. The majority of RB tumors do not show gross alterations in a 4.7-kb fragment (4.7R), which is a candidate RB1 gene. To search for more subtle mutations, the ribonuclease protection method was used to analyze 4.7R messenger RNA from RB tumors. Five of 11 RB tumors, which exhibit normal 4.7R DNA and normal-sized RNA transcripts, showed abnormal ribonuclease cleavage patterns. Three of the five mutations affected the same region of the messenger RNA, consistent with an effect on splicing involving an as yet unidentified 5' exon. The high frequency of mutations in 4.7R supports the identification of 4.7R as the RB1 gene. However, the unusual nature of some of the abnormalities of 4.7 R alleles indicates that the accepted sequence of genetic events involved in the genesis of RB may require reevaluation.
Science 1988 Sep 30
PMID:Identification of germline and somatic mutations affecting the retinoblastoma gene. 317 21

After infection of the respective target cells with the human immunodeficiency virus (HIV-1) viral progeny is produced only after a short temporary delay of some days, depending on cell type. After this period of time a sudden onset of HIV-1 protein synthesis with a dramatic increase in virus release occurs. (2'-5')Oligoriboadenylates [(2'-5')A], capable to activate a latent ribonuclease (RNase L) degrading both mRNA and rRNA, are known mediators involved in the early response of cells to virus infection. Here we show that the (2'-5')A-synthesizing (2'-5')A synthetase, which is inducible by interferon and activated by double-stranded RNA, as well as a (2'-5')A nuclease (2',3'-exoribonuclease) are associated with the nuclear matrix of uninfected and infected H9 cells, also in the absence of interferon. Infection of H9 cells with HIV-1 was found to cause a strong (7.7-fold) enhancement of (2'-5')A synthetase activity and a smaller (2-fold) increase of 2',3'-exoribonuclease activity. Simultaneously the concentration of synthesized (2'-5')A increased 5 to 10 times in isolated nuclei. After incubation for 2 to 3 days both enzyme activities reached a maximum and then dropped below their initial values. Concomitantly a drastic increase in virus production occurred, as judged by reverse transcriptase activity in the culture fluid. These results suggest that the (nuclear matrix-associated) (2'-5')A system might be important during the initial stage of HIV infection, also by destructing matrix-bound viral messengers.
Biol Chem Hoppe Seyler 1988 Sep
PMID:Alteration of nuclear (2'-5')oligoriboadenylate synthetase and nuclease activities preceding replication of human immunodeficiency virus in H9 cells. 322 94

Isolated pancreatic acini from streptozocin-induced diabetic rats were used to study the role of insulin on the synthesis of specific cellular proteins. When acini were incubated with 0-100 nM insulin for 2 h and then pulsed with [35S]methionine, a dose-dependent increase in [35S]methionine incorporation into total cellular proteins was observed. When acinar cell lysates were subjected to gel electrophoresis, 12 major newly synthesized protein bands were resolved. Insulin (100 nM) increased the incorporation of [35S]methionine into all bands but with significantly different rates, varying from 84 to 216% of control. Next, specific antibodies to amylase, trypsin, ribonuclease, myosin, and lactate dehydrogenase (LDH) were used to evaluate the biosynthesis of known proteins. Insulin stimulated labeled amino acid incorporation into amylase by 148% over control. Insulin stimulated the synthesis of trypsinogen to a similar degree, but ribonuclease synthesis showed a significantly smaller increase of 53% over control. Insulin stimulated myosin and LDH synthesis by 169 and 184%, respectively. A differential pattern of protein synthesis was also observed when acini were treated with two other stimulators of protein synthesis, cholecystokinin and hemin. Both of these stimulators had a reduced effect on ribonuclease synthesis compared with amylase and trypsinogen synthesis but failed to increase myosin synthesis. When the RNAs extracted from control acini and acini treated with 100 nM insulin were translated in vitro, the proteins synthesized were quantitatively similar. This study therefore indicates that insulin has translational effects on acinar protein synthesis, and these effects are nonparallel for various specific acinar cell proteins.
Diabetes 1987 Sep
PMID:Insulin and other stimulants have nonparallel translational effects on protein synthesis. 330 74


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