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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) DNA polymerases were highly purified from infected HeLa BU cells by DEAE cellulose, phosphocellulose and DNA cellulose column chromatography. DNA exonuclease activity but not endonuclease activity was found associated with both types of DNA polymerase. Both DNA polymerase activities could be activated by salt in a similar fashion with the optimal activity in the range of ionic strength between 0.22 and 0.29 alpha. At an ionic strength of 0.14, spermidine and putrescine in the concentration range (0--5 mM) studied could mimic the action of KCI in stimulating DNA polymerase activity. Spermine, in the same concentration range, had a biphasic effect. At an ionic strength of 0.29 all three polyamines were inhibitory. HSV-1 and HSV-2 DNA polymerase are similar in their column chromatographic behavior, sedimentation rate in sucrose gradient centrifugation, and activation energy, but they differ in their heat stability at 45 degrees C with the HSV-2 enzyme more stable than the HSV-1 enzyme. Kinetic behavior of both enzymes is similar, with Km values for deoxyribonucleoside triphosphates in the range of 5 . 10(-7) to 1.8 . 10(-8) M. IdUTP and dUTP served as apparent competitive inhibitors with respect to dTTP, and AraATP acted as an apparent competitive inhibitor with respect to dATP. AraATP could not replace dATP in the DNA polymerization reaction; in contrast, IdUTP could replace TTP. Phosphonoformic acid behaved as an uncompetitive inhibitor with respect to DNA. The ID(50) value estimated was foind to be dependent on the purity of the DNA polymerase used and the ionic strength of the assay condition. Each DNA-polymerase associated DNA exonuclease had the same stability at 45 degrees C as its DNA polymerase. The associated DNAase activity was inhibited by phosphonoformic acid and high ionic strength of the assay condition.
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PMID:Properties of herpes simplex virus type 1 and type 2 DNA polymerase. 625 Jun 18

The influence of polyamines on various enzymes involved in the excision repair pathway of DNA, such as UV endonuclease, DNA polymerase I, DNA ligase and polynucleotide kinase, and two AP-endonucleases, were studied. The polymerizing activities of DNA polymerase I and polynucleotide kinase were found to be markedly affected by polyamines. In the former enzyme the effect can be attributed to the stabilization of the correct bihelical structure at the 3' end and in the latter case polyamines stabilize the polynucleotide kinase protein itself in the correct oligomeric structure. The effect of polyamines on the hydrolysis of apurinic and apyrimidinic sites in DNA and nucleosome particles were also investigated. Spermine and spermidine were found to be the most efficient polyamines in causing such hydrolysis both in the free DNA and in the nucleosome particles.
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PMID:Effect of polyamines on enzymes involved in DNA repair. 627 78

Adenovirus uncouples DNA replication from polyamine biosynthesis and causes chromosome aberrations in rodent cells. Addition of polyamines protected infected cells from this chromosome damage. Spermine was the only individual polyamine which protected. The diamine oxidase inhibitor aminoguanidine also protected. Neither compound detectably reduced synthesis of viral early proteins. The protective effects of spermine and aminoguanidine were not additive. Maximal protection was obtained when the compounds were added 4.5 h before mitosis, but significant protection was observed up to 1.25 h before mitosis. This suggests that the compounds act in G2. In vitro, spermine bound strongly to DNA and protected it from mild endonuclease attack, but aminoguanidine did neither. We propose that viral infection causes a deficiency in spermine during a critical period G2, possibly accompanied by an increase in endonuclease activity. The resulting chromosome damage can be prevented by adding exogenous spermine, or by inhibiting the oxidative degradation of endogenous spermine.
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PMID:Spermine and aminoguanidine protect cells from chromosome aberrations induced by adenovirus during the G2 phase of the cell cycle. 707 55

Poly (dG-dC) . poly(dG-dC) was modified by the reaction with N-acetoxy-N-acetyl-2-aminofluorene. The conformations of poly(dG-dC) . poly(dG-dC) and of poly d(G-C)AAF were studied by circular dichroism under various experimental conditions. In 95% ethanol, the two polynucleotides adopt the A-form. In 3.9 M LiCl, the transition B-form-C-form is observed with poly(dG-dC) . poly (dG-dC) but not with poly d(G-C)AAF. In 1 mM phosphate buffer, poly d(G-C)AAF behaves as a mixture of B- and Z-form, the relative percentages depending upon the amounts of modified bases. The percentage of Z-form is decreased by addition of EDTA and is increased by addition of Mg++. Spermine favors the Z-form in modified and unmodified polynucleotides. No defect in the double helix of poly d(G-C)AAF is detected by SI endonuclease.
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PMID:Conformational changes of poly(dG-dC) . poly(dG-dC) modified by the carcinogen N-acetoxy-N-acetyl-2-aminofluorene. 723 16

The worldwide spread of carbapenemase producing Enterobacteriaceae isolates has become a major threat of public health. This worrisome situation leads the development of new methods for carbapenemase screening, detection, prevention of spread and epidemiological data collection as mandatory. In this study, it was aimed to investigate existence and distribution of carbapenemase-encoding genes (CEGs) among carbapenem-resistant Enterobacteriaceae isolated from various clinical samples in Ankara University Faculty of Medicine, Ibni Sina Hospital, Central Microbiology Laboratory between June 2010-May 2014 and detect their clonal relationship. A total of 112 non-repetitive Enterobacteriaceae isolates which were intermediate or resistant to ertapenem were identified by using Phoenix (BD Diagnostic Systems, Sparks, USA) automated microbiology system. After DNA extraction from the isolates, 11 carbapenemase-encoding genes (CEGs) (bla_IMP, bla_VIM, bla_SPM, bla_KPC, bla_NDM, bla_OXA-48, bla_GIM, bla_SIM, bla_AIM, bla_DIM ve bla_BIC) were detected with PCR. The clonal relationship among the isolates was determined by PFGE method following digestion with Xbal DNA macrorestriction endonuclease. Among 112 isolates Klebsiella pneumoniae was the most frequent (n= 79, 70.5%) bacteria followed by Escherichia coli (n= 15, 13.4%), Enterobacter cloacae (n= 10, 8.9%), Enterobacter aerogenes (n= 4, 3.6%) and Klebsiella oxytoca (n= 4, 3.6%) respectively. bla_OXA-48 was the most frequent gene detected. Among 83 (74.1%) isolates bla_OXA-48 was detected alone and in 7 (6.3%) of the isolates it was identified with bla_VIM gene coexistence. bla_VIM gene was identified as the second most frequent CEG among the isolates. bla_VIM gene was detected positive in 9 (8%) isolates. bla_NDM gene was identified in 2 (1.8%) isolates. Ten of the K.pneumoniae isolates with identical PFGE pattern were named as pulsotype B. These isolates were found to be similar in terms of isolate location, isolation dates, antibiotic resistance patterns and the carbapenemase genes they carry, and are considered to be potential outbreak isolates originated from intensive care units. On the other hand CEGs were found in the clinical samples obtained from five out-patients suggesting that community-acquired infections may also arise due to carbapenemase producing Enterobacteriaceae in our country where blaOXA-48 producers are endemic. According to this study, bla_OXA-48 producing gram negative bacteria were frequent in our hospital. The prevalance of bla_VIM gene among metallo-beta-lactamases and coexistence with bla_OXA-48 gene was remarkable. The frequency of blaNDM producing isolates in our hospital was not detected as high yet. In this study, the identification of carbapenemase producing bacteria as outbreak strains in our hospital indicated that cross-sectional surveillance for carbapenemase-producing bacteria from each patient was valuable in terms of early diagnosis of outbreaks.
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PMID:[Investigation of carbapenemase genes and molecular epidemiology of Enterobacteriaceae strains isolated between 2010-2014 in a university hospitals]. 2964 25

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