A Deoxyribonuclease Which Requires Nucleoside Triphosphate from Micrococcus lysodeikticus I. PURIFICATION AND CHARACTERIZATION OF THE DEOXYRIBONUCLEASE ACTIVITY

摘要: Abstract A novel deoxyribonuclease, which requires the presence of nucleotide for reaction, has been purified approximately 2300-fold from cell-free extracts Micrococcus lysodeikticus. This enzyme degrades native, double-stranded DNA at about 40-fold greater rate than thermally denatured DNA. Evidence complete dependence on ATP as well Mg++ ion found. The optimum pH is around 9.4. behaves an endonuclease, yielding primarily oligonucleotides consisted di-, tri-, tetra-, and pentanucleotides along with some larger fragments terminated by 5'-phosphoryl group. average chain length a limit digest 5.5. decrease in viscosity substrate relative to appearance acid-soluble form not so rapid this that observed pancreatic DNase. kinetic analysis means sedimentation sucrose density gradient indicates clearly initial added disappears progressively during reaction enzyme, being replaced much more slowly sedimenting material, products intermediate size between these two components are detectable. These results suggest mechanism digestion appears be one-by-one type.