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)

(1) RNase Ms was inactivated by iodoacetate. The inactivation was most rapid at pH 6.0, and was inhibited in the presence of a denaturant such as 8 m urea or 6 m guanidine-HCL. (2) Competitive inhibitors protected RNase Ms from inactivation by iodoacetate; the effect was in the order 2',(3')-GTP greater than 2',(3')-AMP, 2',(3')-UMP greater than or equal to 2',(3')-CMP. The order is not consistent with that of the binding constants of the 4 nucleotides towards RNase Ms (A is greater than C greater than G greater than U). (3) RNase Ms was inactivated with the concomitant incorporation of one molar equivalent of carboxymethly group. The following evidence indicated that the carboxymethyl group was incorporated into the carboxyl group of an aspartic acid or glutamic acid residue. (i) The carboxymethyl group incorporated into RNase Ms was liberated by treatment with 0.1 n NaOH or 1 m hydroxylamine. (ii) The amino acid composition of carboxymethylated RNase Ms (CM RNase Ms) after acid hydrolysis is similar to that of RNase Ms. (4) 14C-Labeled CM RNase Ms was digested successively with alkaline protease and amino-peptidase M. The radioactive amino acid released was eluted just before aspartate on an amino acid analyzer. After hydrolysis with 6 n HCL, glutamic acid was produced exclusively from the radioactive amino acid. The specific radioactivity of this amino acid calculated from the radioactivity and glutamic acid formed was practctically the same as that of CM RNase Ms. Thus, it was concluded that a carboxymethyl group was incorporated at the carboxyl group of a glutamic acid residue of RNnase Ms. (5) CM RNase Ms bound with 2'-AMP to the same extent as native RNase Ms, but bound to a lesser extent with 2',(3')-GMP. (6) Although the conformation of CM RNase Ms as judged from the CD spectrum was practically the same as that of native RNase Ms, the reactivity of CM RNase Ms towards dinitrofluorobenzene was different from that of native RNase Ms, indicating some difference in the conformation. (7) These results indicate that one glutamic acid residue is involved in the active of RNase Ms.
...
PMID:Carboxymethylation of a minor ribonuclease from Aspergillus saitoi. 47 29

In the presence of Mg(2+) and a specific dinucleotide primer (ApG or GpG), the influenza virion transcriptase synthesizes the eight discrete segments of complementary RNA (cRNA) containing polyadenylic acid (Plotch and Krug, J. Virol. 21:24-34, 1977). Virions were examined for their ability to cap and methylate cRNA containing di- or triphosphorylated 5' termini. By using the primers ppApG, pppApG, or ppGpG, viral cRNA was synthesized in vitro with [alpha-(32)P]-GTP and S-[methyl-(3)H]adenosylmethionine as labeled precursors. DEAE-Sephadex chromatography of the RNase T2 digest of the cRNA product demonstrated no (3)H incorporation at all and the absence of a (32)P-labeled cap structure. The 5' terminus of ppApG-primed cRNA could be capped and methylated by enzymes from vaccinia virus, indicating that the two 5'-terminal phosphates derived from the primer were preserved in the product cRNA. The cap structure formed by the vaccinia enzymes and released by RNase T2 digestion as m(7)GpppA(m)pGp was radioactively labeled at its 3'-terminal phosphate only when [alpha-(32)P]CTP was used as the labeled precursor during transcription. This indicates that the 5'-terminal sequence of the cRNA is ppApGpC and that, therefore, ppApG most probably initiates transcription exactly at the 3' GpCpU(OH) terminus of the virion RNA templates. Virions were also tested for their ability to cap and methylate ppApG in the absence of transcription. No such activities were detected, whereas under the same conditions the vaccinia virus enzymes successfully capped and methylated this compound. Consequently, these experiments, together with those reported earlier, have not detected in influenza virions any capping and methylating enzymes active on the 5'-initiated termini of viral cRNA chains synthesized in vitro, whether these termini possess one, two, or three phosphates. Some mechanism for capping and methylation of viral cRNA must, however, exist, because the viral mRNA (cRNA) synthesized in the infected cell contains 5'-terminal methylated cap structures (Krug et al., J. Virol. 20:45-53, 1976). Possible mechanisms are discussed.
...
PMID:Absence of detectable capping and methylating enzymes in influenza virions. 70 57

DNA-dependent RNA polymerase class C (or III) has been solubilized from either uninfected or adenovirus-2-infected HeLa cells and purified by chromatography on phosphocellulose, DNA-cellulose, CM-Sephadex and DEAE-Sephadex. The last column separated the enzyme into three forms CI, CII and CIII, which were completely free of RNA polymerases class A and B and of DNase and RNase. The total and the relative amount of these different enzyme C forms did not vary whether purified from uninfected or infected cells. Irrespective of the stage of purification, the three enzyme forms transcribed deproteinized adenovirus-2DNA very efficiently. This transcription was highly sensitive to elevated ionic strength (especially in the presence of Mg2+) and was accompanied by continuous reinitiation as shown by adding poly(rI), a potent inhibitor of initiation. In addition heparin-resistant initiation complexes could be formed at elevated temperature. The RNA synthesized in vitro on deproteinized intact adenovirus-2 DNA by the different forms of RNA polymerase class C, has been characterized. Analysis of the transcripts by gel electrophoresis, RNA self-annealing, hybridization to separated adenovirus-2 DNA strands and to restriction endonuclease (BamHI, HindIII), adenovirus-2 DNA fragments have demonstrated that restriction endonuclease (BamHI, HindIII), adenovirus-2 DNA fragments have demonstrated that the various regions of the adenovirus-2 genome were randomly transcribed. In addition, hybridization of RNA transcripts labelled at their 5' end by either [gamma32P]ATP or [gamma-32P]GTP indicated that not only elongation but also initiation occurred randomly through the entire adenovirus-2 genome, irrespective of the form of the enzyme and of the origin of the cells (normal or infected). The results are discussed in terms of the components which are possibly involved in specific transcription.
...
PMID:Transcription in vitro of adenovirus-2 DNA by RNA polymerases class C purified from uninfected and adenovirus-infected HeLa cells. 71 Apr 51

Prior investigation of the protein synthesizing properties of mitochondria involved the whole organelle. In order to better characterize these properties, the present study was concerned more specifically with the activity of the inner mitochondrial membranes (IMM) which recent investigation has implicated as the primary location of mitochondrial ribosomes. To further define mitochondrial protein synthesis simultaneous experimentation was also conducted utilizing cytoplasmic ribosomes thus enabling both qualitative and quantitative comparison between the two systems. Results from this series of investigations reveal a dramatic amino acid incorporating ability by the IMM fraction of the brain mitochondria. This activity, in turn, was shown to be highly independent of exogenous sources of ATP, GTP, pH 5 enzymes, and cytoplasmic ribosomes. Furthermore, the addition of an exogenous source of messenger RNA, polyuridylic acid or (poly (U)) which resulted in an increased incorporation of [14C]phenylalanine into polypeptide in the cytoplasmic system was found to have no effect on the IMM system. Upon comparison of the in vitro protein synthesizing properties of the IMM fraction with those of the cytoplasmic ribosomal system, it became evident that obvious differences existed in the degree of amino acid incorporation and in the sensitivity of this process to the various protein synthesizing inhibitors. Cytoplasmic ribosomes demonstrated a much greater [14C]leucine and [14C]phenylalanine incorporating activity than the IMM fraction. In addition, RNase and cyclohexamide had their greatest effect on the cytoplasmic system while the action of chloramphenicol was most potent on the IMM system. Although puromycin inhibited both protein synthesizing systems, this effect was greatest in the presence of cytoplasmic ribosomes.
...
PMID:In vitro protein synthesis by inner membranes of rat brain mitochondria. 73 21

Nuclei from seminal vesicle epithelium of adult guinea pigs were isolated in hypertonic sucrose solution. The incorporation of [3H]UTP by the isolated nuclei into acid-precipitable products was studied. Incorporation required ATP, GTP, CTP, UTP, and Mg+2. It was inhibited by addition of actinomycin D, deoxyribonuclease, or pyrophosphate to the reaction mixture. Thus, incorporation of [3H]UTP by isolated nuclei had the same characteristics that have been demonstrated for the reactions catalyzed by nuclear RNA polymerases. Using alpha-amanitin as a metabolic tool, we established concentrations of (NH4)2SO4. Mg+2, and nucleotides that give maximum assayable activities of nuclear RNA polymerases I and II. When the activities of polymerases I and II were measured in isolated seminal vesicle nuclei of guinea pigs that had been castrated 4 days earlier, a marked decrease in activities was found relative to control values (nuclei from intact animals). No further decrease was found 8 days after castration. Diminished accessibility to the nuclear DNA template and a decrease in the concentration of RNA polymerase molecules seemed to be responsible for the observed effects of castration on activities of RNA polymerases. An increase in ribonuclease activity did not seem to be responsible for the effects of castration. Activities of the enzymes did not change 2, 3, or 4 hours after intraperitoneal injection (2 mg/kg body weight) of each of five different androgens. Similarly, a single intraperitoneal injection of testosterone did not restore enzyme activity of polymerade I or II at any time during the first 24-hour period after hormone administration.
...
PMID:RNA polymerase activities in isolated nuclei of guinea pig seminal vesicle epithelium: influence of castration and androgen administration. 90 9

The pH 5 supernatant fractions prepared from homogenates of tissues of normal and dystrophic mice were used to study the incorporation of [14C]phenylalanyl-tRNA into peptide. The incorpoation was markedly reduced using the muscle pH 5 supernatant fraction from dystrophic animals but no reduction was seen with brain, liver or heart preparations from dystrophic mice. The lower incorporation with dystrophic muscle pH 5 supernatant was not due to altered activity of ribonuclease, elongation factors, proteolytic enzymes, GTP or sulfhydryl reagents, but was attributable to the presence of activity that was inhibitory to protein synthesis.
...
PMID:Protein synthesis in dystrophic muscle. Activity of the pH 5 supernatant fraction of muscle in dystrophic mice. 95 5

A subcellular system is described which is capable of in vitro synthesis of large nuclear RNA and the formation of both cap I [m7G(5')pppXmpYp] and capII [m7G(5')-pppXmpYmpZp] structures. This system, which consists of partially purified intact nuclei and residual cytoplasmic tags, carries out both guanosine addition, utilizing GTP, and the appropriate methylation reactions, utilizing S-adenosylmethionine as the methyl donor. The general structure of the caps was verified by analyses of methylated derivatives recovered after RNase T2 hydrolysis and after digestion with P1 nuclease, bacterial alkaline phosphatase,and nucleotide pyrophosphatase. Cap formation in large nuclear RNA species was found to be closely associated with transcription, as indicated by alpha-manitin sensitivity and a requirement for the presence of all four nucleoside triphosphates. Recovery of a class of cap II structures, in which only the methyl group at position Y is labeled, as well as capII structures in which all methylated constituents are labeled, indicates the presence of at least two independent methylation events in the in vitro system.
...
PMID:Synthesis methylation, and capping of nuclear RNA by a subcellular system. 99 Feb 62

Optimum conditions for in vitro RNA synthesis by the entomopoxvirus from Amsacta moorei, except for a temperature optimum of 26 degrees, were similar to those reported for vaccinia. Incorporation of 3H-ATP in the presence of CTP, GTP and UTP was significantly inhibited by actinomycin D; incorporation of 3H-ATP alone was not. The products formed by incorporation of 3H-ATP alone or with the three other nucleotides contained polyadenylic acid sequences. The sedimentation coefficient of the 3H-ATP-labeled product formed in the presence of CTP, GTP and UTP was reduced from 8-23S to 3-5S after RNase treatment. The product formed from 3H-ATP alone had an apparent sedimentation value of 3-5S.
...
PMID:RNA polymerase activity of Amsacta moorei entomopox virions. 118 49

DNA-dependent RNA polymerase from Escherchia coli was used to transcribe chromatin from human leukocytes and purified human DNA. RNA was labeled at the 5' terminus with either [gamma-32P]ATP or [gamma-32P]GTP and internally with [3H]UTP. Determination of the average chain length of the RNA molecules by the ratio of moles of 3H-labeled nucleotide incorporated to moles 32P-labeled nucleotide incorporated showed that the size of the transcript of purified DNA was about 2 1/2 times greater than those from chromatin. The percentage of chains initiated with ATP and GTP was observed to vary with the template, the ATP to GTP ratio being greater on chromatin. The kinetics of 3H and 32P hybridization of transcripts of purified DNA showed hybridization primarily to nonrepetitive sequences. Transcripts from the chromatin templates when hybridized to DNA showed a larger proportion of RNase resistance of the 32P-termini at low Cot's.
...
PMID:Template restriction in human chromatin. 126 Aug 58

Cloning of the genes encoding distinct subtypes of human alpha 2-adrenergic receptors (alpha 2-AR) allows the separate recombinant expression of each individual subtype in heterologous systems. We report here the transfection, selection and preliminary pharmacological characterization of two mammalian cell lines, adherent Shionogi S115 mouse mammary tumour cells and human B-lymphoblastoid IBW4 cells growing in suspension, expressing the human alpha 2-AR subtypes alpha 2-C4 and alpha 2-C10 at densities of approx. 2 x 10(5) receptors/cell. Transfection of the subtype genes was verified using a specific RNase protection assay. Pharmacological characterization was carried out with [3H]rauwolscine binding, which was inhibited by oxymetazoline and prazosin in a subtype-selective manner. The sensitivity of (-)-noradrenaline binding to the GTP-analogue 5'-guanylylimidodiphosphate suggested that the receptors are coupled to G-proteins. This was verified in S115 cells by efficient inhibition of forskolin-stimulated cAMP production by the alpha 2-AR agonists, (-)-noradrenaline and clonidine. These cell lines thus appear to be suitable for pharmacological studies on receptor function and ligand binding.
...
PMID:Stable expression of recombinant human alpha 2-adrenoceptor subtypes in two mammalian cell lines: characterization with [3H]rauwolscine binding, inhibition of adenylate cyclase and RNase protection assay. 131 4


<< Previous 1 2 3 4 5 6 7 8 9 Next >>

---