Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presence of a nuclear DNA polymerase in mouse sperm from adult testes has been confirmed and the properties of this enzyme further investigated. This activity was shown to be greatly enhanced by treating the spermatozoa with methanol or ethanol before incubation in the reaction medium or by their addition in small amounts to this medium. It was protected against degradation by nuclear proteases by adding soybean trypsin inhibitor and was stimulated by ATP. It was found to be Mg2+ dependent (optimum concentration: 7.5 mM), DNA dependent, and all four deoxynucleoside triphosphates were needed for optimal reaction. The radioactive acid-precipitable product of polymerization was not eliminated by organic solvents, nor by pronase, ribonuclease or by nuclease S1; however, it was converted to a large extent to acid-soluble products by pancreatic deoxyribonuclease. Since it was only partially solubilized by Triton X-100, it therefore did not appear to be preferentially associated with the nuclear membranes. The activity recovered after incubation depended also on the pH (optimum at pH 8.3) and did not work well in a medium for DNA polymerase alpha. The temperature for maximum incorporation of nucleotides was found to be 32 degrees C and, under our conditions, the reaction was linear for 30 min. The DNA polymerase activity was inhibited by low and high concentrations of KCl. It was not lowered by N-ethylmaleimide or p-hydroxymercuribenzoate; urea slightly stimulated the reaction and this stimulation was reversed by subsequent treatment with N-ethylmaleimide. Actinomycin D (40 mug/ml), ethidium bromide (25--50 muM), netropsin (5--50 mug/ml), and spermidine (0.5--2.5 mM) lowered the polymerization of DNA precursors. The nuclear enzyme could shift from the endogenous template to activated exogenous calf thymus DNA, the resulting nuclear radioactivity being reduced. The endogenous DNP template ability was not increased by deoxyribonuclease activation according to the method of Aposhian and Kornberg (J. Biol. Chem. (1962) 237, 519--525) suggesting that the amount of DNA polymerase associated with chromatin was probably limiting the reaction. The DNA polymerase activity detected in mouse sperm nuclei has numerous properties of low molecular weight DNA polymerases (DNA polymerase beta) reported in several eukaryotic organisms.
 ...
PMID:Further characterization of a DNA polymerase activity in mouse sperm nuclei. 1 3

Previous studies on the refolding of recombinant bovine carbonic anhydrase B (CAB) indicated that polyethylene glycol (PEG) significantly enhanced the recovery of active protein by reducing aggregation. To further test the ability of PEG to enhance refolding, three recombinant human proteins, deoxyribonuclease (rhDNAse), tissue plasminogen activator (rhtPA), and interferon-gamma (rhIFN-gamma) were refolded in the presence of PEG (3350 MW). rhDNAse produced from CHO cells was denatured in 7.2 M urea and refolded by rapid dilution to 4.0 M urea and 0.20 mg/ml protein. When a final PEG to rhDNAse molar ratio of 5 to 1 (0.1 milligram PEG, 3350 MW) was used in the dilution buffer, refolding was improved by 30% to yield complete recovery of active protein. Impure E. coli derived inclusion body preparations of rhDNAse were solubilized in 8 M urea and refolded by dilution to 4 M urea and 0.10 mg/ml protein. Refolding with a dilution buffer which yielded a final PEG to rhDNAse molar ratio of 10 to 1 (0.1 milligram PEG, 3350 MW) resulted in a three-fold increase in the recovery of active protein. When PEG was used in the dilution buffer, aggregation of rhDNAse did not occur during refolding in either case. rhtPA produced from CHO cells was denatured in 5 M guanidine hydrochloride (GuHCl) and refolded by rapid dilution to 0.10 M GuHCl and 0.20 mg/ml protein.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Polyethylene glycol enhanced protein refolding. 136 98

The location of the phosphodiester bond cleaved by homogeneous Mg2+-dependent apurinic endodeoxyribonuclease (EC 3.1.25.2; APE) of bovine calf thymus has been determined by using a 21-mer oligonucleotide containing a single central apurinic site as a substrate. A single product of cleavage consistent with cleavage of the oligonucleotide 5' to the apurinic site, and leaving a 3' hydroxyl group, was identified. This enzyme is, therefore, a class II apurinic endonuclease. The substrate specificities of this enzyme have been determined by using a variety of natural and synthetic DNAs or oligonucleotides containing base-free sites. Calf thymus APE has an absolute requirement for a double-stranded DNA and requires an abasic site as a substrate. The presence of a base fragment such as a urea residue, an alkoxyamine group attached to the C'-1 position of the abasic site, or reduction of the C'-1 aldehyde abolishes the APE activity of this enzyme. Synthetic abasic sites containing either ethylene glycol, propanediol, or tetrahydrofuran interphosphate linkages are excellent substrates for bovine APE. These results indicate that APE has no absolute requirement for either ring-opened or ring-closed deoxyribose moieties in its recognition of DNA-cleavage substrates. The enzyme may interact with the pocket in duplex DNA that results from the base loss or with the altered conformations of the phosphodiester backbone that result from the abasic site.
 ...
PMID:Mechanism of DNA cleavage and substrate recognition by a bovine apurinic endonuclease. 247 77

Homogenates of Giardia lamblia trophozoites exhibited the following hydrolase activities: acid phosphatase (EC 3.1.3.2), proteinase (EC 3.1.4) with urea-denatured hemoglobin and N-benzoyl-DL-arginine-2-naphthylamide as substrates, deoxyribonuclease (EC 3.1.4.5), and ribonuclease (EC 2.7.7.16). beta-N-Acetylglucosaminidase (EC 3.2.1.30), beta-galactosidase (EC 3.2.1.23), beta-glucuronidase (EC 3.2.1.31), alpha-D-glucosidase (EC 3.2.1.20), beta-D-glucosidase (EC 3.2.1.21), and beta-D-xylosidase (EC 3.2.1.37) activities were below the level of detection. Differential and isopycnic centrifugation of homogenates demonstrated that giardial hydrolases were localized in a single-particle population sedimenting at 7200g for 30 min. The particles had a buoyant density in sucrose of 1.15 and exhibited latency. Latency was completely destroyed by Triton X-100 or 15 cycles of freezing and thawing. After centrifugation of Triton- or freeze-thaw-treated particle fractions, the hydrolase activities, though no longer latent, were still sedimentable suggesting tight binding to the organelle membrane. Latency was destroyed simultaneously for all hydrolases, in direct proportion to the amount of Triton added to a particle preparation or to the number of times a particle preparation was subjected to freezing and thawing. These results support the suggestion that the hydrolases of G. lamblia trophozoites are localized in a single-particle population of lysosome-like organelles.
 ...
PMID:Giardia lamblia: localization of hydrolase activities in lysosome-like organelles of trophozoites. 327 50

Sterile, concentrated culture supernatant from Pasteurella haemolytica (biotype A, serotype 1) strain 630 was subjected to physical, chemical, and immunologic treatments to determine their influence on leukotoxin (cytotoxin) activity contained in the supernatant. Each treated sample contained approximately 8 chemiluminescence inhibitory units of leukotoxin. Treatment effects were evaluated for their ability to inactivate leukotoxin activity. Leukotoxin activity in treated samples was determined by inhibition of the luminol-dependent chemiluminescence response of bovine neutrophils. Optimal leukotoxin synthesis by P haemolytica occurred when the bacteria were at the logarithmic growth phase, whereas stationary phase cultures contained minimal amounts of leukotoxin activity in their culture supernatant. Leukotoxin activity was heat labile; activity was substantially decreased when concentrated culture supernatant samples containing leukotoxin activity were incubated at 37 C for several hours. When concentrated culture supernatant was incubated at progressively decreasing temperatures, there was a progressive increase in the length of time that the leukotoxin retained its biologic activity. Samples stored at -70 C retained activity for at least 2 months. Leukotoxin activity was nondialyzable and was able to withstand considerable extremes in hydrogen ion concentration. Leukotoxin activity could not be pelleted when subjected to forces of 100,000 X g for 1 hour. Chemical and enzymatic studies suggested that P haemolytica leukotoxin contained carbohydrate and protein moieties. Chemical treatment with 0.2% sodium lauryl sulfate, 0.5% sodium deoxycholate, 7.5 mM EDTA and 8M urea with 8 mM 2-mercaptoethanol and enzymatic treatment with lipase, ribonuclease, and deoxyribonuclease had no discernible effect on leukotoxin activity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Pasteurella haemolytica leukotoxin: physicochemical characteristics and susceptibility of leukotoxin to enzymatic treatment. 396 75

Two bacteriocins (boticins) were elaborated without induction by strain S5, a nontoxigenic variant of Clostridium botulinum type E. After separation of the two active entities by gel filtration on Sephadex G-50, a large particle with boticin activity was isolated by density gradient ultracentrifugation, and a small soluble boticin was purified by continuous curtain electrophoresis and chromatography on sulfoethyl-Sephadex. Large and small boticins were purified 200- and 3,000-fold, respectively, with yields of 50% or more. The small boticin, a basic substance with molecular weight under 30,000, was the predominant species; the large boticin, a negatively charged particle with particle weight greater than 40 x 10(6), represented less than 20% of the total activity. Both purified boticins were resistant to heat and were attacked by proteolytic enzymes, but the large boticin was less thermostable and less sensitive to proteolytic enzymes than was the smaller variety. The activity of the large boticin was not reduced by treatment with urea or deoxyribonuclease. Both boticins exhibited sporostatic and bactericidal activities for C. botulinum type E, strain 070. A suspension of type E strain 070 vegetative cells was rendered nonviable within 9 min by the small boticin. The lethal action of this bacteriocin was not reversed by trypsin.
 ...
PMID:Purification and some properties of two boticins. 491 45

Auletta, Angela E. (Catholic University, Washington, D.C.), and E. R. Kennedy. Deoxyribonucleic acid base composition of some members of the Micrococcaceae. J. Bacteriol. 92:28-34. 1966.-Thirty-seven strains from the genera Micrococcus, Staphylococcus, Gaffkya, and Sarcina were examined for deoxyribonucleic acid base composition and biochemical activity. Organisms were tested for production of catalase, coagulase, deoxyribonuclease, oxidase, phosphatase, hydrogen sulfide, indole, and acetoin; nitrate reduction; gelatin, starch, and urea hydrolysis; citrate and ammonium phosphate utilization; NaCl tolerance; growth at 10 and 45 C, and growth in litmus milk. They were tested for production of acid from dextrose and mannitol under anaerobic conditions, and for aerobic production of acid from dextrose, mannitol, lactose, sucrose, raffinose, maltose, xylose, and glycerol. Organisms could be divided into two groups on the basis of guanine-cytosine (GC) content. Group I had an average GC content of 32%, and included all organisms which produced acid from dextrose. Group II had an average GC content of 62%, and included those organisms incapable of producing acid from dextrose under anaerobic conditions. Sarcina ureae had a GC content of 43%.
 ...
PMID:Deoxyribonucleic acid base composition of some members of the Micrococcaceae. 594 Dec 82

Alysiella bovis adheres to surfaces by means of short, ruthenium red-staining, rod-like fimbriae. The fimbriae remain associated with the cell envelope of A. bovis, even when sonicated or exposed sequentially to toluene, Triton X-100, lysozyme, ribonuclease, and deoxyribonuclease. Adhesion of outer membrane-derived cell wall ghosts of A. bovis to glass was inhibited by IO4-, sodium dodecyl sulfate, urea, pronase, and trypsin. Protease treatment digested the fimbriae from the distal end, and exposure to sodium dodecyl sulfate depolymerized the fimbriae. Exposure of ghosts to 1% sodium dodecyl sulfate preferentially solubilized a 16,500-dalton protein which was subsequently purified by gel filtration and demonstrated to be a glycoprotein (ca. 17% carbohydrate). Antibodies raised against the 16,500-dalton glycoprotein agglutinated whole cells and inhibited adhesion of ghosts to glass.
 ...
PMID:Mechanism of adhesion of Alysiella bovis to glass surfaces. 620 60

Purpura was grossly observable in albino mice 6 to 8 h after the intraperitoneal injection of sterile, deoxyribonuclease-treated, cell-free extracts prepared by sodium deoxycholate-induced lysis, sonic disruption, Parr bomb treatment, autolysis without sodium deoxycholate, or alternate freezing and thawing of washed suspensions of Streptococcus pneumoniae type I. Cell-free extracts obtained from sonically disrupted, heat-killed cells (100 degrees C for 20 min) did not contain purpurogenic activity. The reaction was maximal at approximately 24 h postinjection, started to fade slowly after 24 to 48 h, and usually was not grossly observable by 4 to 6 days postinjection. The purpura-producing principle (PPP) in the cell-free extract was purified by sequential ammonium sulfate precipitation, protamine sulfate precipitation, Sepharose 6B gel filtration, wheat germ lectin-Sepharose 6MB affinity chromatography, ribonuclease and trypsin treatment, and a second Sepharose 6B gel filtration step. The final preparation (i) contained glucosamine (5.6%), muramic acid (8.0%), neutral carbohydrate (12.8%), phosphate (8.0%), orcinol-reactive material (6.0%), and Lowry-reactive material (1.6%), and (ii) was free of detectable amounts of deoxyribonucleic acid, capsular polysaccharide, neuraminidase, cytolysin, and hyaluronidase. The isoelectric point and molecular size of the PPP were approximately pI 3.0 and several million daltons, respectively, and the activity remained in the supernatant fluid after centrifugation for 1 day at 105,000 x g. PPP activity was destroyed by incubation with egg white lysozyme and sodium metaperiodate but was resistant to trypsin, pronase, alpha-amylase, deoxyribonuclease, ribonuclease, alkaline phosphatase, pancreatic lipase, 7% trichloroacetic acid, 6 M urea, autoclaving (121 degrees C) for 30 min, and mild acid and alkali exposure. Our observations indicate that the PPP requires intact beta-1,4-glucosidic linkages for activity and support the working hypothesis that activity is associated with pneumococcal peptidoglycan solubilized by the bacterium's autolysin.
 ...
PMID:Characterization of pneumococcal purpura-producing principle. 624 53

Spirosomes, very find spiral particles, were isolated from a protoplastlysate of Lactobacillus brevis ATCC 8287 by differential centrifugation and purified further by potassium tartrate density gradient centrifugation. The purified spirosome preparation showed a maximum peak around 275 nm on the ultraviolet absorption spectrum and it consisted of about 94.5% protein. The buoyant density in CsCl of the spirosomes was 1.320 g/cm3. The spirosomes were composed mainly of a single protein (spirosin with an apparent molecular weight of about 95,000 as determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The protein of the spirosomes was found to be composed predominantly of neutral amino acids accompanied by approximately equal amounts of acidic and basic amino acids. The spirosomes showed one antigenic determinant in the immunodiffusion test. The spirosomes were readily degraded by the action or proteolytic enzymes and lost their antigenicity, but they were not affected by treatment with either deoxyribonuclease or ribonuclease. The spiral structure of the spirosome was also found to be disintegrated by treatment with 1 M guanidine hydrochloride, 4 M urea or 0.1% SDS, but not by the action of deoxycholate, nonionic detergents or mercaptoethanol, as observed in the electron microscope.
 ...
PMID:Purification and characterization of spirosomes in Lactobacillus brevis. 710 79


1 2 Next >>