Eucaryotic primase

Abstract

Eucaryotic primase, an enzyme that initiates de novo DNA replication, is tightly associated with polymerase α or yeast DNA polymerase I. It is probably a heterodimer of 5.6 ± 0.1 S. The enzyme synthesizes oligoribonucleotides of about eight residues which are always initiated with a purine. In vitro the polymerase–primase complex initiates synthesis and pauses at preferred sites on natural single‐stranded templates. The relative concentrations of ATP and GTP present in the reaction medium modulate the frequency of site recognition. Primase is strongly ATP‐dependent in the presence of single‐stranded DNA and of poly(dT). It also synthesizes oligo(rG) in the presence of poly(dC) very efficiently. Copyright © 1987, Wiley Blackwell. All rights reserved