Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Preparations of human leukocyte interferon obtained by multi-stage purification procedure exhibited ribonuclease activity with the optimum at pH 7.0--7.5. The enzyme possessed the endonuclease action mechanism. Most substances studied for their effect on the RNA-ase activity in human interferon preparations showed many of them to act on the enzyme in the same way as on other ribonucleases. However, dithioerythritie, a reducing agent for disulfide bounds, activated the ribonuclease in the interferon preparation, as distinct from the pancreatic ribonuclease, which was inhibited by this preparation. Patterns of protein and RNA-ase distribution were obtained by electrophoresis in polyacrylamide gel.
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PMID:[Ribonuclease activity in preparations of human leukocyte interferon]. 0 77

Escherichia coli, strain AB 1157, cells are capable of translating human, mouse, and chicken messenter RNA for interferon with production of interferon of the corresponding specifity. This translation occurs in the presence of serum. The activity of the resulting interferon decreased in parallel to dilution of the original mRNA preparation, upon multiple ulitization of the mRNA solution, as well as upon reduction of the interferon- producing activity of cells-donors of mRNA due to prolonged storage of the cells. Unlike animal cells, the bacteria do not require pre-treatment with actinomycin D. The interferon translated by bacteria is inactivated by trypsin and resistant to ribonuclease.
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PMID:Translation by bacterial cells of messenger RNA for interferon of animal origin. 2 28

Although poly(I) is generally considered to be inactive as an interferon inducer, we have found several authentic poly(I) preparations to be effective inducers. Their interferon inducing ability varied considerably from one cell system to another. In human diploid fibroblasts, primed with interferon and superinduced by cycloheximide and actinomycin D, all active poly(I) samples proved nearly as effective in inducing interferon as poly(I).poly(C). In primary rabbit kidney cell cultures, the active poly(I) samples were either as active, or 3 to 30 times less active than poly(I).poly(C). In intact rabbits they were 100 times less active than poly(I).poly(C). Except for one particular sample, all active poly(I) preparations were inferior to poly(I).poly(C) when assayed for interferon induction in interferon-treated mouse L cells; in DEAE-dextran-treated L cells, they induced little, if any, interferon. The poly(I) inducers of interferon were considerably more susceptible to degradation by TI ribonuclease, pancreatic ribonuclease and human serum nuclease(s) than was poly(I).poly(C) when assayed under the same conditions. Due to their limited half-life time in biological fluids, poly(I) analogues such as those described here may offer a greater safety margin in clinical use than poly(I).poly(C).
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PMID:Interferon inducing activity of polyinosinic acid. 9 86

Incubation of the mouse L-cell-free system with a concentration of pppA2'p5'A2'p5'A [(2'-5')An] just sufficient to inhibit protein synthesis results in formation of a high-molecular-weight, heatlabile inhibitor and enhanced ribonuclease activity and in the rapid breakdown of (2'-5')An to ATP. The (2'-5')An-enhanced ribonuclease activity is also unstable and in the absence of a (2'-5')-An-regenerating system inhibiton of protein synthesis is transient. Although interferon treatment enhances the synthesis of (2'-5')An, the rates of degradation of (2'-5')An and levels of activatible nuclease are similar in extracts prepared from control or interferon-treated cells. Interestingly, the sensitivity of different cell-free systems to (2'-5')An, varies with the source of the cell-free systems and with the methods used in their preparation. There is, however, no obvious correlation between the sensitivities of the system and the rate of breakdown of (2'-5')An. The significance of these results is discussed in relation to a possible control function for the (2'-5')An system in both interferon-treated and control cells.
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PMID:Synthesis and breakdown of pppA2'p5'A2'p5'A and transient inhibiton of protein synthesis in extracts from interferon-treated and control cells. 21 47

Interferon produced by rainbow trout gonadal cells (RTG-2) was partially purified. The physical, chemical, and biological properties of this in vitro produced fish cell interferon were studied. Purification was achieved by ultracentrifugation, molecular sieve gel chromatography, ion exchange chromatography, and polyacrylamide gel electrophoresis. The isoelectric point of RTG-2 interferon, as determined by CM-Sephadex (C-50) chromatography, was 7.1. Filtration through Sephadex G-150 showed that RTG-2 interferon had a molecular weight of 94,000. The partially purified material was not sedimented at 105,000 times g for 2 h at 4 C. The fish cell interferon was non-dialyzable and exhibited heat and pH stability. The partially purified material was inactivated by treatment with trypsin or 2-mercaptoethanol, but was resistant to treatment with deoxyribonuclease or ribonuclease. RTG-2 interferon which was induced by infectious pancreatic necrosis virus exhibited antiviral activity against challenge with infectious hematopoietic necrosis virus or infectious pancreatic necrosis virus. Partially purified RTG-2 interferon exhibited greater species specificity than the crude material.
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PMID:Partial purification and characterization of RTG-2 fish cell interferon. 23 93

Extracts of interferon-treated HeLa cells adsorbed to poly(I) . poly(C)-agarose have been used to synthesize 2'5'oligo(A). This oligonucleotide has been characterized by enzymatic digestion with alkaline phosphatase, snake venom phosphodiesterase, T2 ribonuclease and chromatography on DEAE, and PEI-cellulose. The oligonucleotide inhibits protein synthesis in vitro and activates an endonuclease present in extracts of control and interferon-treated cells. The metabolic stability of 2'5'oligo(A) has been investigated in these cell extracts. The oligonucleotide undergoes rapid degradation, particularly in the absence of ATP and of an energy regenerating system. Furthermore, the 2'5'oligo(A)-activated endonuclease reverts to an inactive state under these conditions, but can be reactivated upon further addition of 2'5'oligo(A). A possible role for the degradation of 2'5'oligo(A) in the mechanism of interferon action is discussed.
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PMID:Metabolic stability of 2' 5'oligo (A) and activity of 2' 5'oligo (A)-dependent endonuclease in extracts of interferon-treated and control HeLa cells. 42 14

The activity of 2',5'-oligoadenylate synthetase, an enzyme recently discovered in interferon-treated cells, was found in lymphocytes from normal mouse spleen that had received neither exogenous interferon nor its inducers. The oligoadenylate synthesized by lymphocyte cell extracts inhibited protein synthesis in rabbit reticulocyte lysates. The oligomers were composed mainly of trimer and were resistant to digestion by T2 ribonuclease. The level of the enzyme in lymphocytes was about 20 to 30% of that in L929 cells treated with interferon. The activity of the enzyme was further enhanced in lymphocytes in vitro by addition of interferon. The 2',5'-oligoadenylate synthetase was distributed among several lymphoid tissues, but was not detected in cell extracts from brain or liver. The enzyme may play an important role in the regulation of the immune system.
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PMID:2',5'-Oligoadenylate synthetase activity in lymphocytes from normal mouse. 50 Jun 92

Crude human lymphoblastoid interferon has less ribonuclease activity than equivalent primary leukocyte interferon and ribonuclease was eliminated when it was purified. The methods used differed from those that had failed to eliminate similar activity from leukocyte interferon. This result makes it unlikely that exogenous ribonuclease plays a major role in the antiviral action of interferon preparations.
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PMID:Ribonuclease activity of preparations of human lymphoblastoid interferon. 50 37

In sensitive cells interferon (IFN) induces many genes leading to an increased production of several different proteins. One of these gene products is the enzyme oligoadenylatesynthetase (OAS). The main effect of this IFN induced enzyme activation is the production of oligonucleotides (2-5A) from cellular ATP. The 2-5A activates an endogeneous ribonuclease (RNase), which cleaves rRNA and mRNA. The sum of these effects is degradation of cellular and viral RNA, resulting in reduced protein synthesis. Taken together, IFN, OAS and 2-5A exist as a part of immune defence system primarily directed against virus infections. Furthermore, it is possible that this system under normal, physiological conditions regulates the growth of somatic cells. The virus inhibiting effect of IFN has been useful in the treatment of viral infections and certain types of cancer. Probably, the IFN dependent enzyme systems will achieve a greater therapeutic significance in the future.
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PMID:[Interferon, oligoadenylate synthetase and oligoadenine nucleotide--a cell biological triad]. 169 81

Primary chick embryo cells which were "aged" in vitro and exposed to poly(rI).poly(rC) developed a disproportionately high degree of resistance to virus challenge in relation to the amount of conventional acid-stable interferon (IFN) produced. Cells were often highly resistant after exposure to a few nanograms of poly(rI).poly(rC) which gave rise to little or no acid-stable IFN. Study of the mechanism(s) responsible showed that this antiviral state was not due to the double-stranded ribonuclease induced in parallel, nor to residual poly(rI).poly(rC) (which this ribonuclease destroyed), but to the production of a hitherto undescribed acid-labile chicken IFN.
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PMID:Interferon induction by viruses. XX. Acid-labile interferon accounts for the antiviral effect induced by poly(rI).poly(rC) in primary chick embryo cells. 170 94


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