Purification and Properties of Deoxyribonucleic Acid Polymerase from Nuclei of Sea Urchin Embryos

Abstract Deoxyribonucleic acid polymerase has been purified from nuclei of rapidly dividing sea urchin embryos, Strongylocentrotus franciscanus and Strongylocentrotus purpuratus. No gross differences between the enzymes from the two species were observed. The DNA polymerases are heat-labile and are stabilized in the presence of polyglycols. This enhanced stabilization was exploited throughout the purification procedure. The enzymes, purified more than 300-fold, have a molecular weight of approximately 150,000. However, under certain conditions larger aggregates have also been noted. No DNase activity was detected in the most purified fraction. The DNA polymerase activity is totally dependent on the presence of added DNA. For maximum activity the presence of all four deoxynucleoside triphosphates and Mg++ are required. Native double stranded DNA is a more effective primer than single stranded DNA. Native DNA which has been degraded to a limited extent with pancreatic deoxyribonuclease is the most efficient primer.