title: The assay and isolation of DNA rings using an ATP-dependent endonuclease.
abstract: The ATP-dependent endonuclease from Hemophilus influenzae is relatively inactive on closed or open DNA rings, yet rapidly hydrolyzes single- or double-chained linear DNA. This enzyme in combination with an exonuclease (exo VII) has been shown to spare various circular DNA molecules including those having single-chain regions of significant length. However, rings containing single-chained regions are broken at a rate depending on the length of these regions. By admixing a linear DNA of alternate radiolabel, a simple assay for DNA rings has been developed. The application of this procedure to the assay of folded rings from Drosophila DNA is demonstrated.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D004270:DNA, Circular / Q000032:analysis* / Q000302:isolation & purification; D004279:DNA, Viral / Q000032:analysis* / Q000302:isolation & purification; D003851:Deoxyribonucleases / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006193:Haemophilus influenzae / Q000201:enzymology; D007700:Kinetics; D008433:Mathematics; D009690:Nucleic Acid Conformation; D013539:Simian virus 40; D013997:Time Factors
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D000255:Adenosine Triphosphate; D003851:Deoxyribonucleases; D004720:Endonucleases