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)

It was found that cyanide can partially reverse as well as arrest the transformation of a newly transformed deoxyribonuclease-treated culture for 6 to 8 min after the addition of the enzyme. These findings strongly suggest that deoxyribonucleic acid which attained deoxyribonuclease-insensitivity is not necessarily in the cell, but stored in some region peripheral to the membrane, and that a rate-limiting, energy-dependent step is required to transport this deoxyribonucleic acid into the cell.
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PMID:Early energy-dependent step in the entry of transforming deoxyribonucleic acid. 498 55

Endonuclease V of bacteriophage T4 binds to UV-irradiated deoxyribonucleic acid (DNA) but not to unirradiated DNA. We have developed an assay to detect this binding, based on the retention of enzyme--DNA complexes on nitrocellulose filters. The amount of complex retained, ascertained by using radioactive DNA, is a measure of T4 endonuclease V activity. The assay is simple, rapid, and specific, which makes it useful for detecting T4 endonuclease V activity both in crude lysates and in purified preparations. We have used it to monitor enzyme activity during purification and to study binding of the enzyme to DNA under conditions that minimize the ability of the enzyme to nick DNA. From our data we conclude that (1) T4 endonuclease V binds to UV-irradiated DNA but not to DNA that has been previously incised by the endonuclease, (2) equilibrium between the free and complexed form of the enzyme is attained under our reaction conditions, (3) dissociation of enzyme--DNA complexes is retarded by sodium cyanide, and (4) retention of enzyme--DNA complexes on nitrocellulose filters is enhanced by high concentrations of saline--citrate.
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PMID:Binding of T4 endonuclease V to deoxyribonucleic acid irradiated with ultraviolet light. 624 30

Reductive methylation and site-directed mutagenesis experiments have implicated the N-terminal alpha-amino group of T4 endonuclease V in the glycosylase and abasic lyase activities of the enzyme. NMR studies have confirmed the involvement of the N-terminal alpha-amino group in the inhibition of enzyme activity by reductive methylation. A mechanism accounting for these results predicts that a (imino) covalent enzyme-substrate intermediate is formed between the protein N-terminal alpha-amino group and C1' of the 5'-deoxyribose of the pyrimidine dimer substrate subsequent to (or concomitantly with) the glycosylase step. Experiments to verify the existence of this intermediate indicated that enzyme inhibition by cyanide was substrate-dependent, a result classically interpreted to imply an imino reaction intermediate. In addition, sodium borohydride reduction of the intermediate formed a stable dead-end enzyme-substrate product. This product was formed whether ultraviolet light-irradiated high molecular weight DNA or duplex oligonucleotides containing a defined thymine-thymine cyclobutane dimer were used as substrate. The duplex oligonucleotide substrates demonstrated a well-defined gel shift. This will facilitate high-resolution footprinting of the enzyme on the DNA substrate.
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PMID:Evidence for an imino intermediate in the T4 endonuclease V reaction. 834 26

Some properties of the cell-free and cell-associated hemolysins of Escherichia coli were studied. Several strains of E. coli that were isolated from intestines of pigs with edema disease produce large quantities of cell-free hemolysin when grown in the presence of an extract of meat. The component of meat that stimulates production of cell-free hemolysin is not extracted by lipid solvents and is not dialyzable. The cell-free hemolysin is an acidic substance that occurs in two forms. It is inactivated by trypsin but not by lecithinase, lysozyme, ribonuclease, or deoxyribonuclease, shows optimum activity between pH 7 and 8, and requires calcium ion for activity. It does not appear to be an enzyme. The kinetics of the lytic reaction are most consistent with the hypothesis that one molecule of cell-free hemolysin is sufficient to lyse one erythrocyte and that it is inactivated in the lytic reaction. The cell-free hemolysin does not sufficiently damage the cell during the prelytic period to cause lysis after the hemolysin-calcium-erythrocyte complex has been disrupted. The cell-associated hemolysin was not separated from the cell by autolysis, freezing, sonic treatment, or treatment with trypsin or lysozyme. It appears to be closely associated with the metabolic status of the cell. Organisms that are highly hemolytic under usual conditions of assay immediately lose most of their hemolytic capability in the presence of sodium cyanide, streptomycin, nalidixic acid, and rifampin.
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PMID:Properties of the Hemolytic Activities of Escherichia coli. 1655 36

Some effects of two uncouplers of oxidative phosphorylation on infection of Escherichia coli K12 by bacteriophage lambda deoxyribonucleic acid (DNA) are described. Dinitrophenol did not interfere with the initial interaction of the cells with free DNA, and neither dinitrophenol nor carbonyl cyanide m-chlorophenylhydrazone affected the linear portion of the infection reaction. However, the process by which lambda-DNA bound to the bacterial cell became insensitive to deoxyribonuclease was strongly inhibited by both uncoupling agents. These results support the conclusion that successful infection of E. coli with phage lambda-DNA is coupled to cellular energy metabolism and localize a portion of the infection reaction which is sensitive to the uncoupling of oxidative phosphorylation. Possible energy-requiring steps in the infection process are discussed.
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PMID:Effects of uncouplers of oxidative phosphorylation on the infection of Escherichia coli K12 by phage-lambda DNA. 1861 68