DNA polymerase

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Specific polymerases

Characteristics

Extension rate

  • How rapidly a particular DNA polymerase enzyme synthesizes a complementary strand.

Processivity

  • A measure of how strongly the polymerase binds to template DNA. Processivity doesn't affect extension rate. However, it has a strong influence on the absolute length of complementary DNA strand that can be made.

Proofreading

  • Proofreading is when the multi-functional enzyme adds a deoxynucleotide and then goes back and rechecks the template to complement interaction to make sure the correct nucleotide was added.
  • Proofreading polymerases are usually multimeric and thus more expense to make.
  • Like all DNA polymerases, proofreading polymerases add an adenine deoxynucleotide to the 3' end of the complementary strand. Proofreading ensures that this nucleotide is removed again leaving blunt-ended DNA.