What is DNA polymerase in prokaryotes

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Area of ‚Äč‚ÄčExpertise - Biochemistry, genetic engineering

The enzyme DNA polymerase catalyzes the synthesis of DNA polynucleotides by attaching nucleoside phosphates to a strand of DNA. The substrates are the four different 2'-deoxyribonucleotides dATP, dGTP, dCTP and dTTP, with each extension step forming a new phosphodiester bond and releasing pyrophosphate. The synthesis always proceeds in the direction from 5 'to 3', i.e. the newly added nucleotide building block is attached to the free 3'-hydroxyl group of the growing DNA polymer. DNA polymerases cannot de novo- Carry out synthesis of DNA, but basically require a so-called primer made of DNA or RNA, with which the first new nucleotide can be linked.

Three types of DNA polymerase, referred to as Pol I, Pol II, and Pol III, have been identified in bacteria. Pol III is the main polymerase used to replicate genomic DNA before cell division. It has 3 '-> 5' exonuclease activity, which is a proof-readingFunction enables. Pol I is involved in DNA repair processes and has both 5 '-> 3' and 3 '-> 5' exonuclease activity. Pol II appears to play a role in the replication of damaged DNA. Different types of DNA polymerases also exist in eukaryotic cells, but the number of variants is greater.

See also: Taq polymerase

Learning units in which the term is dealt with

Genetic engineering tools45 min.

biochemistryWorking methodsGenetic engineering

Presentation of the most important enzymes and their use in genetic engineering