1986 Volume 11 Issue 3 Pages 311-316
DNA polymerase α combined with the endoplasmic reticulum (ER) was isolated from unfertilized sea urchin eggs. NaCl treatment of this fraction released DNA polymerase α from the ER. The molecular size (the S value) of the ER-free DNA polymerase α changed with the concentration of NaCl used; being 23 S, 11-15 S and 6-8 S in the presence of 0.05-0.12 M, 0.12-0.24 M and more than 0.24 M NaCl. DNA polymerase α activity decreased concomitantly with the reduction in molecular size. The 6-8 S form of DNA polymerase α did not aggregate by itself nor with other cellular components nonspecifically, when the 23 S form was present. These results are evidence of the presence of 6-8 S DNA polymerase α as a high molecular weight form (23 S-form) in sea ruchin eggs.