DNA polymerase-beta from the nuclear fraction of sea urchin embryos: characterization of the purified enzyme.
Approximately 2,500-fold purifications of DNA polymerase-beta from the nuclear fraction of blastulae of the sea urchin, Hemicentrotus pulcherrimus, was performed. The enzyme preparation, which was devoid of DNase and terminal deoxynucleotidyl transferase as contaminants, showed a sedimentation constant of 3.0 S in a sucrose density gradient, a molecular weight of 50,000 by gel filtration, and an isoelectric point of pH 8.1. The enzyme activity was resistant to sulfhydryl group inhibitors. Its optimal pH was 9.0-9.5 in Tris-maleate buffer and 10.0 in glycine buffer. The optimal NaCl concentration for the activity was 30-60 mM and about half of the activity remained at 0.4 M NaCl. As a template-primer, the enzyme preferred synthetic homopolymers to activated DNA. The order of this preference was as follows; poly (dA)-oligo (dT)12-18 greater than poly (rA)-oligo (dT)12-18 greater than activated DNA. The above results indicate that the enzyme corresponds to DNA polymerase-beta from vertebrate cells.
D000818:Animals; D002413:Cations, Divalent; D002467:Cell Nucleus / Q000201:enzymology*; D004257:DNA Polymerase II / Q000302:isolation & purification / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D007700:Kinetics; D012617:Sea Urchins / Q000201:enzymology*; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D002413:Cations, Divalent; D013439:Sulfhydryl Reagents; D004257:DNA Polymerase II; D004259:DNA-Directed DNA Polymerase