title: The deoxyribonucleic acid polymerases from the diatom Cylindrotheca fusiformis. Partial purification and characterization of four distinct activities.
abstract: Four extramitochondrial DNA polymerases from the marine photosynthetic diatom Cylindrotheca fusiformis were isolated and purified more than 1200-fold by chromatography on DNA-cellulose and DEAE-Sephadex. The enzymes were equally susceptible to inhibition by the thiol-blocking agents N-ethylmaleimide and p-chloromercuribenzoate, the zinc chelator o-phenathroline, and the nucleic acid interchelators ethidium bromide and acriflavin; they displayed similar pH optima, preferred activated DNA, and had strict dependence on high K+ for maximum activity. They were differentiated on the basis of their kinetic parameters, template-primer utilization and salt requirements. The four activities varied with growth stage of C. fusiformis. Activities of polymerases A and D doubled in exponential-phase cells as compared with those in stationary-phase cells, and the increase in polymerase B and chloroplast activity C was 20-40%. The relationship of the diatom polymerases to the complements in other organisms is discussed.
mesh_terms: D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004259:DNA-Directed DNA Polymerase / Q000302:isolation & purification / Q000378:metabolism*; D003854:Deoxyribonucleotides / Q000494:pharmacology; D056890:Eukaryota / Q000201:enzymology* / Q000254:growth & development; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D019384:Nucleic Acid Synthesis Inhibitors; D011188:Potassium / Q000494:pharmacology; D013698:Templates, Genetic
chemical_list: D003854:Deoxyribonucleotides; D019384:Nucleic Acid Synthesis Inhibitors; D008345:Manganese; D004259:DNA-Directed DNA Polymerase; D011188:Potassium