DNA replication enzymology

1 DNA polymerases. The growth of a DNA chain is catalyzed by DNA polymerase (DNA nucleotidyltransferase, EC2.7.7.7), which requires template, primer, all four dNTP and Mg +  

Template The nucleotide added is selected according to the sequence of the pre-exishng DNA chain serving as the template to which the primer anneals via basepairing. 

Primer The nucleohde is added to the 3 -OH of the terminal nucleotide of the RNA primer (-20 nucleotides), which is synthesized by primase. 

Deoxyribomcleoside-5 -triphosphate substrates All four dNTPs must be present. Triphosphates provide energy necessary for polymerizahon. 

Polarity The DNA chain grows in the 5 3 direchon, thus the newly synthesized chain is antiparallel to the tanplate. 

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One area of basic biochemical research that has paid unexpected dividends is DNA replication. Enzymological work here has characterized the various DNA polymerases in bacterial and eukaryotic cells. With progress in the biochemical characterization of these enzymes, new applications have been found for them in research... 

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