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

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Query: EC:3.1.25.1 (deoxyribonuclease)
1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ribonuclease activity has been extracted from adult guinea-pig epidermis by sequential homogenization in dilute sodium acetate and sulfuric acid. The extracts were subjected to ammonium sulfate fractionation and to affinity and ion exchange chromatography. Three ribonucleases (I, II, III) were separated from the sodium acetate extract and 6(A, B1, B2, B3, C, D) were isolated from the sulfuric acid extract. The degree of purification varies from 65-fold to 8,700-fold and the apparent molecular weights of the active forms of 8 of the 9 ribonucleases range from 10,000 to 36,500. No phosphodiesterase activity is present in any of the 9 fractions, but there is alkaline phosphatase activity in one (I) and deoxyribonuclease activity in a second (B3). Two of the ribonucleases have acid pH optima (a1, B3), while the others are most active between PHs 6.8 and 7.8. The activity of 4 of the fractions is sensitive to added EDTA (III, A, B2, B3,), but no stimulatory metal ions were found. Low concentrations of the polyamine spermidine enhanced the activity of 3-fractions (III, C, D). Yeast ribonucleic acid is degraded exonucleolytically by 2 fractions (I, A) and endonucleolytically by the remaining 7. In experiments with homopolyribonucleotide substrates, poly U was generally the preferred substrate. Substantial hydrolysis of poly A occurred with 2 fractions (A, B3) and slight hydrolysis of poly G with 2 other fractions (B2, C).
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PMID:Epidermal nucleases. II. The multiplicity of ribonucleases in guinea-pig epidermis. 1 63

Protease-free bovine pancreatic deoxyribonuclease (DNase) (1.6 X 10(-4) mmol) was thiolated on the NH2 groups with N-acetyl-DL-homocysteine thiolactone (2.4 X 10(-2) mmol) at pH 10.5 with imidazole (2.4 X 10(-2) mmol) as the catalyst in the presence of 4,4'-dithiodipyridine (4.2 X 10(-2) mmol). The product obtained after 16 h at 4 degrees C, 2-acetamido-4-(4'-dithiopyridyl)butyryl-DNase, isolated by gel filtration, contained an average of 0.87 +/- 0.13 mol of mixed disulfide per mol of DNase. Ribonuclease (RNase) was thiolated in a similar manner, but under N2 in the absence of 4,4'-dithiodipyridine. The protein N-acetylhomocysteinyl-RNase contained on the average 0.94 +/- 0.11 mol of sulfhydryl groups per mol of RNase. The coupling of RNase ot DNase was accomplished by thiol-disulfide interchange at pH 6.2 and 25 degrees C for 90 min. The hybrid enzyme (yield 25--33%, based upon the DNase derivative used) was freed from unreacted DNase, RNase, and homodimers by gel filtration, affinity chromatography, and salting-out chromatography. The purified enzyme contained one molecule each of DNase and RNase and hydrolyzed thymus deoxyribonucleic acid (DNA) and yeast or transfer ribonucleic acid (RNA) with 75 and 40% of the efficiencies, respectively, of the parent enzymes. The RNA strand of the hybrid substrate, phage f1 DNA-[3H]RNA, prepared from phage DNA with RNA polymerase, was hydrolyzed rapidly by the hybrid enzyme but was not hydrolyzed by RNase alone. A conjugate of the two enzymes offers the possibility in vivo of delivering two enzymes that differ in size, charge, and biological function to the same site at the same time.
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PMID:Preparation of the bifunctional enzyme ribonuclease-deoxyribonuclease by cross-linkage. 48 31

In this report we describe a specific staining procedure for detection of ribonucleic acid (RNA), based on bromination of uracil and subsequent immunohistochemical visualization of 5-bromouracil in RNA. This method is applicable for both cryostat and glycol methacrylate (GMA)-embedded sections. Cryostat sections must be fixed in formaldehyde, whereas tissue pieces to be embedded in GMA are fixed in cold acetone. Before bromination, sections must be treated with trypsin. Bromination was performed in a solution of bromine in potassium bromide. After bromination, excess bromine was removed with sodium bisulfite. The monoclonal antibody MoBu-1 specifically bound to brominated RNA. Ribonuclease digestion, in contrast to deoxyribonuclease digestion, abolished staining. This method makes possible precise localization of RNA, especially well demonstrated in plastic-embedded sections.
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PMID:Specific demonstration of ribonucleic acid by chemical bromination and immunohistochemistry. 246 88

A component in extracts of Group A streptococci suppresses antibody formation in mice against heterologous erythrocyte and protein antigens. Large doses are not toxic and repeated injection does not change its effectiveness. It is most effective when injected 1 or 2 days before antigen and it is not suppressive when given after antigen. The active factor occurs as a large polydisperse complex and activity can be increased 10- to 25-fold by filtration through Sepharose 2B. Both direct (gammaM) and indirect (gammaG) antibody-forming cells are suppressed in primary and secondary responses. Injection before a primary response does not reduce memory cell development. It increases rather than depresses the "background" antibody-forming cells to sheep erythrocytes, and is equally effective if injected intraperitoneally or intravenously. Ribonuclease increases activity while deoxyribonuclease has no effect. Proteases destroy immunosuppressive action.
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PMID:Biological characterization of an immunosuppressant from group A streptococci. 493 71

The sensitivity of Streptococcus faecalis (ATTC 8043) to S. zymogenes X-14 bacteriocin depends greatly on its physiological age. Sensitivity decreases from the mid-log phase on and is completely lost in the stationary phase. The sensitivity of erythrocytes to the hemolytic capacity of the bacteriocin showed considerable species variation. The order of increasing sensitivity was goose < sheep < dog < horse < human < rabbit. However, when red cell stromata were used as inhibitors of hemolysis in a standard system employing rabbit erythrocytes the order of increasing effectiveness was sheep < rabbit < human < horse < goose. When rabbit cells were used in varying concentrations with a constant hemolysin concentration, there was a lag of about 30 min, which for a given hemolysin preparation was constant for all red cell concentrations. Furthermore, the rate of hemolysis increased with increasing red cell concentration. If red cells are held constant and lysin varied, the time to reach half-maximal lysis varies directly with lysin but is not strictly proportional. Bacterial membranes were one to three orders of magnitude more effective than red cell stromata as inhibitors. The order of increasing effectiveness seems to be Escherichia coli < Bacillus megaterium < S. faecalis < Micrococcus lysodeikticus. In addition to membranes, a d-alanine containing glycerol teichoic acid, trypsin in high concentration, and deoxyribonuclease also inhibited hemolysis. Ribonuclease, d-alanine, l-alanine, dl-alanyl-dl-alanine, N-acetyl-d-alanine, N-acetyl-l-alanine did not inhibit hemolysis.
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PMID:Bacteriocin (hemolysin) of Streptococcus zymogenes. 497 10

Cell-free peptide synthesis by extracts from vegetative cells and spores of Bacillus subtilis was analyzed and compared. The initial rate of phenylalanine incorporation in a polyuridylate-directed system was found to be in a similar range for the two extracts. However, spore extracts frequently incorporated less total phenylalanine as did the vegetative cell system. Optimal conditions for amino acid incorporation by spore extracts were found to be similar to those of vegetative cell extracts. Polyphenylalanine synthesis was stimulated by preincubation of both extracts prior to the addition of polyuridylic acid (poly U) and labeled phenylalanine. Both systems showed a dependence on an energy-generating system and were inhibited by chloramphenicol and puromycin. Ribonuclease, but not deoxyribonuclease, inhibited the reaction significantly. The presence of methionine transfer ribonucleic acid (tRNA(F)) and methionyl-tRNA(F) transformylase was demonstrated in spore extracts. An analysis of several aminoacyl-tRNAs in spores revealed that the relative amounts of these tRNAs were similar to those found in vegetative cells. Only lysine tRNA was found to be present in relatively greater amounts in spores. These results indicate that dormant spores of B. subtilis contain the machinery for the translation of genetic information.
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PMID:Peptide synthesis by extracts from Bacillus subtilis spores. 498 76

Streptococcal DNAse C is more resistant to heat inactivation than the A or B enzyme. DNAses A and C are indifferent to the bacterial ribonucleic acid inhibitor whereas the B enzyme is markedly inhibited. Prolonged digestion with relatively large amounts of DNAse B results in chemical and biological destruction of the inhibitor. Ribonuclease as well as deoxyribonuclease activity is associated with the B enzyme. Both activities require divalent cations and both are inhibited by bacterial ribonucleic acid. The ratios of the two activities are constant in various preparations and after partial heat inactivation. Mutual inhibition of the two activities can be demonstrated in mixed substrate systems. The evidence presented is consistent with the view that the B enzyme is a single nuclease which can attack both deoxyribonucleic and ribonucleic acids.
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PMID:Streptococcal nucleases. I. Further studies on the A, B, and C enzymes. 603 51

To evaluate the specificity and applicability to the study of human tumor cells of the reverse transcription (RT) in situ PCR and RT polymerase chain reaction (PCR) in situ hybridization techniques, we examined five melanoma cell lines and five nonmelanoma lines for tyrosinase mRNA using primers specific for tyrosinase. Each procedural step was optimized and minutely controlled, and results from the in situ techniques and solution-phase RT-PCR were compared. All melanoma lines showed a specific pattern of perinuclear cytoplasmic reaction not seen in nonmelanoma lines. There was exact agreement between the results from the RT in situ PCR and RT-PCR in situ hybridization techniques and those from solution-phase RT-PCR. Ribonuclease digestion abolished cytoplasmic staining, as did omission of the reverse transcriptase step. Nuclear staining was seen in melanoma and nonmelanoma lines, apparently as a result of DNA synthesis from repair-replication and mispriming or nonspecific amplification. Neither high concentrations of deoxyribonuclease nor long incubation periods abolished this effect completely. Demonstration of cytoplasmic mRNA by RT in situ PCR and RT-PCR in situ hybridization specifically identifies cells of melanocytic lineage.
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PMID:Demonstration of cytoplasmic tyrosinase mRNA in tissue-cultured cells by reverse transcription (RT) in situ polymerase chain reaction (PCR) and RT PCR in situ hybridization. 902 34

Immunostaining of the cell cycle-associated Ki-67 antigen was studied, using the Ki-67-specific MIB-1 monoclonal antibody on slides prepared by cytocentrifugation of cultured A375 melanoma cells. Immunomorphological analysis of the Ki-67 immunostaining pattern of both nuclear and nucleolar locations was carried out following pre-treatment of the slides including ribonuclease and deoxyribonuclease pre-digestion of the cells. Immunostaining of nucleolar Ki-67 was reduced by ribonuclease pre-digestion, but was not altered by deoxyribonuclease pre-treatment. Ribonuclease did not reduce the staining intensity of Ki-67 in the nuclear matrix, but the intensity decreased after deoxyribonuclease pre-digestion. We suggest that the Ki-67 molecule may play an important role in ensuring contact between nuclear DNA and nucleolar RNA during transcriptional processes in cell proliferation.
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PMID:Effect of Ribonuclease A and Deoxyribonuclease I on Immunostaining of Ki-67 in Cultured Melanoma Cells. 1117 87

Pollack, J. D. (University of Connecticut, Storrs), Shmuel Razin, and Robert C. Cleverdon. Localization of enzymes in Mycoplasma. J. Bacteriol. 90:617-622. 1965.-Cells of eight parasitic and two saprophytic Mycoplasma strains were lysed by use of osmotic shock, and the membranes were separated from the soluble fraction by use of differential centrifugation. Cell fractions were tested for reduced nicotinamide adenine dinucleotide (NADH(2)) oxidase, reduced nicotinamide adenine dinucleotide phosphate (NADPH(2)) oxidase, glucose-6-phosphate dehydrogenase, adenosine triphosphatase, ribonuclease, and deoxyribonuclease activities. Adenosine triphosphatase was confined to the membrane fraction of all Mycoplasma strains. The NADH(2) oxidase activity was associated with the membranes of the saprophytic M. laidlawii and with the soluble fraction of the parasitic Mycoplasma strains. NADPH(2) oxidase activity was detected only in the soluble fraction of the parasitic strains. Glusose-6-phosphate dehydrogenase was demonstrated only in the soluble fraction of M. laidlawii. Ribonuclease activity was found usually in both membrane and soluble fractions, but was generally higher in the membrane fraction. In the human and bovine Mycoplasma strains, deoxyribonuclease activity could not be demonstrated in the soluble fraction; in the remaining strains, activity was highest in the soluble fraction. Dissolution of M. laidlawii strain B membranes by sodium deoxycholate significantly increased membrane-NADH(2) oxidase and adenosine triphosphatase activities.
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PMID:Localization of Enzymes in Mycoplasma. 1656 57


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