A 'polymerase' (EC 2.7.7.6/7/19/48/49) is an
enzyme whose central function is associated with
polymers of
nucleic acids such as
RNA and
DNA.
The primary function of a polymerase is the polymerization of new DNA or RNA against an existing DNA or RNA template in the processes of
replication and
transcription. In association with a cluster of other enzymes and proteins, they take
nucleotides from solution, and catalyse the synthesis of a polynucleotide sequence against a
nucleotide template strand using base-pairing interactions.
It is an accident of history that the enzymes responsible for the catalytic production of other
biopolymers are not also referred to as polymerases.
One particular polymerase, from the
thermophilic bacterium, ''
Thermus aquaticus'' (''Taq'') (
PDB 1BGX, EC 2.7.7.7) is of vital commercial importance due to its use in the
polymerase chain reaction, a widely-used technique of
molecular biology.
Other well-known polymerases include:
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Terminal Deoxynucleotidyl Transferase (TdT), which lends diversity to antibody heavy chains
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Reverse Transcriptase, an enzyme used by
RNA retroviruses like
HIV, which is used to create a complementary strand to the preexisting strand of viral
RNA before it can be integrated into the
DNA of the
host cell. It is also a major target for antiviral drugs.
See also
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DNA polymerase
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DNA polymerase I
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DNA polymerase II
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DNA polymerase III holoenzyme
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DNA Polymerase IV (DinB) –
SOS repair polymerase
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RNA polymerase
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RNA polymerase I
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RNA polymerase II
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RNA polymerase III
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T7 RNA polymerase