[Isolation and some properties of ATP-dependent DNAse from sea urchin (Strongylocentrotus intermedius) embryo]

Abstract

An ATP-dependent DNAse was isolated from the cells of the sea urchin Strongylocentrotus intermedius embryos by chromatography on DEAE-cellulose and gel chromatography on Sepharose 4B. The enzyme was found homogeneous during polyacrylamide gel electrophoresis. The molecular weight of the enzyme was determined by gel filtration through Sepharose 6B and was equal to approximately 450,000. The sedimentation coefficient as determined by ultracentrifugation was equal to approximately 15S. The pH optimum during native DNA hydrolysis lies within the pH range of 6,5--9,0 and that during hydrolysis of denaturated DNA--within the pH range of 9,0--9,5. The enzyme was activated by ATP and dATP at the optimal concentration of 10(-4) M. Other nucleoside triphosphates did not substitute for ATP in this reaction. The hydrolysis of denaturated DNA occurred via the exonuclease way with a formation of short (di-, tri,- tetra- and penta-) oligonucleotides. The enzyme hydrolyzed native DNA according to the endonuclease type with predominant formation of high molecular weight polynucleotides.