Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bleomycin (BLM) exclusively affects thymidine-containing compounds such as DNA and polydeoxyribonucleotides by releasing free thymine and leaving aldehyde functions. Molecular morphology and base sequence of the DNA strongly influence BLM activity. High BLM concentrations, besides modifying DNA into oligothyminic or athyminic nucleic acids, cause strand scissions. Enzymatic DNA and RNA synthesis is strongly influenced by BLM. The inhibition in DNA-dependent DNA polymerase and DNA-dependent RNA polymerase assays is of the non-competitive type. Protein biosynthesis in in vitro systems is not affected by BLM even at high concentrations. BLM turns out to be a strong inhibitor of DNase I and of DNase II; the inhibition is of the competitive type. The enzymatic activities of nucleases using RNA as substrate (RNase A, RNase B, Rnase T1, venom phosphodiesterase I and spleen phosphodiesterase II) are not influenced by this antibiotic. The antibiotic reduces cell proliferation (L5178y mouse lymphoma cells) in vitro in low concentrations by cytostasis and at higher concentrations by cytotoxicity. In BLM-treated L5178y cells, DNA synthesis is strongly reduced, while RNA and protein synthesis are not affected. In vivo, using growing quail oviducts, cell proliferation and cytodifferentiation are markedly inhibited after BLM treatment. This is attributed to the observed inhibition of DNA synthesis. RNA and protein synthesis as well as gene expression are not influenced by BLM under the conditions used. The selective inhibition of DNA synthesis in vivo may be caused by the following mechanisms: (1) competition of BLM with RNA; (2) blocking of the accessibility of DNA in chromatin to BLM, and (3) dependence from the repair processes. BLM inhibits growth of sarcomas, induced by oncogenic RNA viruses in vivo; well-developed tumours show regression after BLM treatment. Transformation of chick embryo fibroblasts by oncogenic RNA viruses in vitro and growth of these viruses is blocked by BLM; the most sensitive period for BLM inhibition is the time during the first period (integration of viral genome into cellular genome?) after infection.
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PMID:Effect of bleomycin on DNA, RNA, protein, chromatin and on cell transformation by oncogenic RNA viruses. 6 69

Chromatin from trout testis at an early stage of development was digested with DNase II (deoxyribonucleate 3'-oligonucleotidohydrolase; EC 3.1.4.6), and the solubilized products were fractionated into Mg2+-soluble and -insoluble components. An examination of the histones from these fractions by one- and two-dimensional polyacrylamide gels showed that the highly acetylated species of histone H4 (di-, tri-, and tetra-acetylated) were associated mainly with the Mg2+-soluble material. Digestion of this chromatin fraction with pancreatic ribonuclease converted more than half of it to an insoluble state, and the acetylated H4 remained associated with the precipitated fraction. No changes in the other histones were noted, but two other basic proteins were also found to be associated with the Mg2+-soluble fraction. Since this fraction is enriched in transcribing gene sequences, it is concluded that the histone H4 of active genes is present in a highly acetylated state.
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PMID:Acetylated histone H4 is preferentially associated with template-active chromatin. 27 72

Human pancreatic DNase I was purified extensively from duodenal juice of healthy subjects by a procedure including ammonium sulfate fractionation, ethanol fractionation, phosphocellulose fractionation, isoelectric focusing, and gel filtration. The final preparation was free of DNase II, pancreatic RNase, alkaline phosphatase, and protease. The enzyme had a molecular weight of approximately 30,000, as determined by gel filtration on Sephadex G-100, and showed maximum activity at pH 7.2-7.6. It required divalent cations for activity, and caused single-strand breaks by endonucleolytic attack on double- as well as single-stranded DNA molecules. The enzyme was inhibited by actin and bovine pancreatic DNase I antibody.
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PMID:Purification and properties of human pancreatic deoxyribonuclease I. 41 31

Author followed up the activity of the three enzymes involved in the catabolism of nucleic acids--acid deoxyribonulease (DNase II), alkaline ribonuclease (RNase I), and acid ribonuclease (RNase II)--in the denervated gastrocnemius and soleus muscles of rats for 28 postoperative days. The activity of both acid nucleases increased in both types of denervated muscles, compared with the respective controls. Up to the 14th postoperative day, the activity excess of both acid nucleases was more significant in the m. gastrocnemius than in the m. soleus. The RNase I ran below the control activity during the whole period in the m. soleus and up to the 14th day in the m. gastrocnemius. The role of nucleases and nuclease inhibitors in the changes of nucleic acid catabolism in neurogenic muscular atrophies is discussed.
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PMID:Effect of neurectomy on nuclease activity in skeletal muscles of rats. 61 95

The effects of spermine, putrescine, and spermindiol on different nucleases were investigated. A highly active spermine analog, spermindiol, was synthesized, which markedly enhanced DNA hydrolysis by staphylococcal nuclease and spleen DNase II [EC 3.1.4.6] and RNA degradation by staphylococcal nuclease and pancreatic RNase A [EC 3.1.4.22]. Spermindiol also increased the melting temperature of calf thymus DNA.
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PMID:A potent polyamine analog, spermindiol. 101 Aug 53

To clarify the relationship between changes in serum pancreatic enzymes and pathological changes in pancreatic parenchyma, this study was performed by using rat models with acute pancreatitis. The models were rats with edematous and necrotizing pancreatitis. Amylase, lipase, ribonuclease (RNase), and deoxyribonuclease (DNase I, II) in the serum were determined for 48 h after the development of pancreatitis. Amylase and lipase levels rose directly in both pancreatitis groups. These enzymes in the necrotizing pancreatitis group were higher than those in the edematous pancreatitis group, but there was no significant difference. RNase levels also rose markedly, but there was no obvious difference between either of the pancreatitis groups. On the other hand, DNase levels were high in the necrotizing pancreatitis group but low in the edematous pancreatitis group, with significant differences between the two groups, especially in the DNase II levels over a 36-h period (p less than 0.05-0.01). Therefore, these results suggest that serum DNase levels reveal the necrotizing changes in pancreatic parenchyma.
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PMID:Relationship between pancreatic enzymes and pathological changes in the pancreas in acute pancreatitis. The significance of determination of serum deoxyribonuclease. 247 54

Phosphodiesterase I [EC 3.1.4.1] was purified from normal human urine in a highly purified state free from phosphodiesterase II, RNase, DNase I, DNase II, and phosphatase by column chromatographies of DEAE-Toyopearl, butyl-Toyopearl, Affi-Gel blue, and Sephadex G-150. The molecular weight of the enzyme was 1.9 x 10(5) and the pH optimum around 9.0 with p-nitrophenyl deoxythymidine 5'-phosphate as the substrate. The enzyme hydrolyzed the 3'-5' linkage of various dinucleoside monophosphates at approximately the same rate and the phosphodiester bonds of cyclic 3',5'-mononucleotides to produce mononucleoside 5'-phosphate. The enzyme also hydrolyzed ADP to 5'-AMP and Pi, ATP to 5'-AMP and PPi, and NAD+ to 5'-AMP and NMN. The enzyme activity was abolished by removal of metal ions with EDTA, and the metal-free enzyme was reactivated on the addition of Zn2+. The enzyme activity was also abolished by some reducing agents and the inhibition was reversed by Zn2+. The metal-free enzyme was less stable than the native enzyme, and Zn2+ and Co2+ restored the stability of the metal-free enzyme to the level of the native enzyme. The enzyme degraded oligonucleotides and high molecular nucleotides stepwise from the 3'-termini to give 5'-mononucleotides. The enzyme hydrolyzed single-stranded DNA more preferentially than double-stranded DNA. The enzyme also nicked superhelical covalently closed circular phi X174 DNA to yield first open circular DNA and then linear DNA.
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PMID:Phosphodiesterase I in human urine: purification and characterization of the enzyme. 282 85

A trypsin inhibitor was isolated from mouse lymphocytic leukemia L 1210 cells by ammonium sulphate precipitation and preparative isoelectric focusing. A 39-fold purification was attained. The inhibitor is a protein since its activity is destroyed by pronase and it binds to insolubilized trypsin. Two main forms of the inhibitor were found of pH 4.8 and 5.3. The inhibitor is copurified with DNA, although neither DNase II nor RNase A change its activity.
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PMID:Serine proteinase inhibitor from lymphocytic leukemia cells. Properties and copurification with DNA. 325 33

A macromolecule binding 3H-methylcholanthrene (3H-MCA) and 3H-benzo(a)pyrene (3H-BaP) and sedimenting in the 4-5 S region of sucrose gradient (4.5 S) was identified in rat liver cytosol. The binding was displaced by 100-fold molar excess unlabeled ligands whereas 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) was ineffective. The dissociation constant for both polycyclic aromatic hydrocarbons (PAHs) was of the order of 10(-8) M or lower. Both 3H-MCA and 3H-BaP bound to 4.5 S in a non covalent manner, since 92% of the bound radioactivity was extractable with ethyl ether. Furthermore the binding was strongly reduced by urea 8 M and by guanidine. HCl 4 M (99 and 70% respectively). Thin layer chromatography of the ethyl ether-solubilized radioactivity showed a peak comigrating with PAHs used as standards. When chromatographed on Sephadex G-200, 4.5 S was eluted as a sharp peak with an apparent molecular weight of 50-60,000 daltons. Enzyme treatment of liver cytosol showed that the 4.5 S binding sites were destroyed by micrococcal nuclease (92% of inhibition). Papain and phosphodiesterase I and II reduced the binding to 50%, whereas DNase I, DNase II, RNase, phospholipase A2 and C and trypsin were ineffective. These data suggest that the PAHs binding macromolecule of rat liver cytosol is a protein associated with a polynucleotide. The binding of both PAHs was enhanced by increasing the incubation temperature, the maximum being reached after 20-30 min at 37 degrees C. After 2.5 min at 65 degrees C, binding sites were completely destroyed. The same temperature-induced "activation" was obtained also by prewarming the cytosol at 37 degrees C in the absence of ligands.
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PMID:Polycyclic aromatic hydrocarbon binding macromolecules. Identification, characterization and temperature activation of a 4.5 S binding nucleoprotein. 406 Feb 44

The acid deoxyribonucleases [DNase II; EC 3.1.4.6] in human urine were purified approximately 400- to 500-fold by phosphocellulose chromatography, gel filtration on Sephadex G-75 and isoelectric focusing, with a total recovery of 22%. The enzymes were present in a least three forms with different isoelectric points, pHs 6.4, 6.6, and 6.8. However, other properties were essentially similar. The enzymes did not require divalent cations for activity, and the optimal pHs were at 5.1 to 5.3 in 33 mM acetate buffer. They had a molecular weight of around 36,000, as estimated by gel filtration on Sephadex G-75. The enzymes were endonucleases which hydrolyzed native, double-stranded DNA about 5 to 15 times faster than thermally denatured DNA. The products formed from native DNA were 3'-phosphoryl- and 5'-hydroxy-terminated oligonucleotides. The average chain length of the limit digests with these enzymes was approximately 11 to 15, and the major fragments were longer than pentanucleotides. The final preparations were free of nonspecific acid and alkaline phosphatases and phosphodiesterase, but contained contaminating ribonuclease activity.
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PMID:Purification and properties of deoxyribonuclease II from human urine. 624 3


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