title: DNA polymerases from Chlamydomonas reinhardii. Further characterization, action of inhibitors and associated nuclease activities.
abstract: The properties of three DNA polymerase species A, B and C, purified from Chlamydomonas reinhardii were compared. DNA polymerases A and B have Km values with respect to deoxyribonucleoside triphosphates of 19 micron and 3 micron respectively. DNA polymerase A is most active with activated DNA, but will also use native DNA and synthetic RNA and DNA templates with DNA primers. DNA polymerase B is also most active with activated DNA, but will use denatured DNA and synthetic DNA templates. It is inactive with RNA templates. DNA polymerase B is completely inactive in the presence of 100 micron-heparin, which has no effect on DNA polymerase A activity. Heparin dissociates DNA polymerase B into subunits that are still catalytically active, but which heparin inhibited. DNA polymerase B possesses deoxyribonuclease activity that is inhibited by 5 micron-heparin, suggesting that the deoxyribonuclease is an integral part of the DNA polymerase moiety. DNA polymerase A is devoid of nuclease activity. DNA polymerase C is similar to DNA polymerase B in all these properties, though it is more active with RNA primers and has greater heat-sensitivity.
mesh_terms: D002696:Chlamydomonas / Q000201:enzymology*; D004247:DNA / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D007525:Isoelectric Focusing; D019384:Nucleic Acid Synthesis Inhibitors; D011189:Potassium Chloride / Q000494:pharmacology; D012313:RNA / Q000378:metabolism; D013696:Temperature; D013698:Templates, Genetic
chemical_list: D019384:Nucleic Acid Synthesis Inhibitors; D012313:RNA; D011189:Potassium Chloride; D006493:Heparin; D004247:DNA; D004259:DNA-Directed DNA Polymerase; D003851:Deoxyribonucleases