title: Endonuclease activity associated with purified PM2 bacteriophages.
abstract: An endonucleolytic activity is associated with purified PM(2) bacteriophages. It converts the double-stranded supercoiled PM(2) DNA mostly into the linear form that sediments as a homogenous peak in alkaline sucrose gradients. The same activity is found in intact or detergent-lysed phages. Optimal activity is observed between pH 6.8 and 7.5 at 28 degrees . Divalent cations, Mg(2+) or Mn(2+), are necessary for activity, and the enzyme is inhibited by RNA. The endonuclease has no appreciable activity on linear DNA molecules, but it attacks single-stranded circular DNA.
mesh_terms: D001435:Bacteriophages / Q000201:enzymology*; D002250:Carbon Radioisotopes; D002499:Centrifugation, Density Gradient; D004270:DNA, Circular / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D011549:Pseudomonas; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D004270:DNA, Circular; D004279:DNA, Viral; D014316:Tritium; D004720:Endonucleases; D013936:Thymidine