Three DNA polymerases (A, B and C) have been purified from the soluble cytoplasm of ungerminated embryos. Mainly on the basis of chromatographic, template-specificity and salt-inhibition evidence, we have characterized the three enzymes. Other physico-chemical and enzymic properties are described. From purified mitochondria we have purified a DNA polymerase that behaves like DNA polymerase B on chromatographic and template-specificity criteria. Only highly purified enzyme B from the soluble cytoplasm showed an exonuclease activity able to degrade 3′- or 5′-labelled polydeoxyribonucleotides, as well as a ‘proof-reading’ capacity.
Deoxyribonucleic Acid Polymerases from Yeast. Further Purification and Characterization of DNA-Dependent DNA Polymerases A and B