DNA polymerase III from Saccharomyces cerevisiae. II. Inhibitor studies and comparison with DNA polymerases I and II.
The newly identified yeast DNA polymerase III was compared to DNA polymerases I and II and the mitochondrial DNA polymerase. Inhibition by aphidicolin (I50) of DNA polymerases I, II, and III was 4, 6, and 0.6 micrograms/ml, respectively. The mitochondrial enzyme was insensitive to the drug. N2-(p-n-butylphenyl)-2'-deoxyguanosine 5'-triphosphate strongly inhibited DNA polymerase I (I50 = 0.3 microM), whereas DNA polymerase III was less sensitive (I50 = 80 microM). Conditions that allowed proteolysis to proceed during the preparation of extracts converted DNA polymerase II from a sensitive form (I50 = 2.4 microM) to a resistant form (I50 = 2 mM). The mitochondrial DNA polymerase is insensitive (I50 greater than 5 mM). With most other inhibitors tested (N-ethylmaleimide, heparin, salt) only small differences were observed between the three nuclear DNA polymerases. Polyclonal antibodies to DNA polymerase III did not inhibit DNA polymerases I and II, nor were those polymerases recognized by Western blotting. Monoclonal antibodies to DNA polymerase I did not crossreact with DNA polymerases II and III. The results show that DNA polymerase III is distinct from DNA polymerase I and II.
D000911:Antibodies, Monoclonal; D016590:Aphidicolin; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors*; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors*; D004258:DNA Polymerase III / Q000037:antagonists & inhibitors*; D003848:Deoxyguanine Nucleotides / Q000494:pharmacology; D004224:Diterpenes / Q000494:pharmacology; D007700:Kinetics; D019384:Nucleic Acid Synthesis Inhibitors; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D000911:Antibodies, Monoclonal; D003848:Deoxyguanine Nucleotides; D004224:Diterpenes; D019384:Nucleic Acid Synthesis Inhibitors; D016590:Aphidicolin; C040364:N(2)-(4-n-butylphenyl)-2'-deoxyguanosine 5'-triphosphate; D004256:DNA Polymerase I; D004257:DNA Polymerase II; D004258:DNA Polymerase III