title: Primed and unprimed synthesis of poly (dA-dT) by calf thymus DNA polymerase alpha.
abstract: The primed and unprimed synthesis of poly(dA-dA-dT) by calf thymus DNA polymerase alpha (DNA nucleotidyltransferase; deoxynucleoside triphosphate: DNA deoxynucleotidyltransferase EC 2.7.7.7) has been compared to replication of activated DNA. Synthesis of poly(dA-dT) by alpha-polymerase is both autocatalytic and exponential. The rate of synthesis of poly(dA-dT) is markedly affected by the Mg2+ concentration and has a higher temperature optimum than replication of activated DNA, implicating "slippage" as a necessary part of poly(dA-dT) replication. Calf thymus 24,000-dalton unwinding protein influences poly(dA-dT) synthesis by increasing both the exponential rate constant and the rate of linear synthesis. Single-stranded template poly(dA-dT) is provided alpha-polymerase by both "strand slippage" and melting by unwinding protein.
mesh_terms: D000818:Animals; D002417:Cattle; D004257:DNA Polymerase II / Q000378:metabolism*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D011067:Poly dA-dT / Q000096:biosynthesis*; D011089:Polydeoxyribonucleotides / Q000096:biosynthesis*; D013698:Templates, Genetic; D013950:Thymus Gland / Q000201:enzymology*
chemical_list: D011089:Polydeoxyribonucleotides; D011067:Poly dA-dT; D004257:DNA Polymerase II; D004259:DNA-Directed DNA Polymerase; D008274:Magnesium