Polymerase

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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:

• Terminal Deoxynucleotidyl Transferase (TDT), which lends diversity to antibody heavy chains

• 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.

[edit] See also

• DNA polymerase
  • DNA polymerase I
  • DNA polymerase II
  • DNA polymerase III holoenzyme
  • DNA Polymerase IV (DinB) – SOS repair polymerase

• RNA polymerase
  • RNA polymerase I
  • RNA polymerase II
  • RNA polymerase III
  • T7 RNA polymerase

v • d • e Transferases: Phosphotransferases/kinases (EC 2.7) 2.7.1 - OH acceptor Hexo- - Gluco- - Fructo- (Hepatic fructo-) - Galacto- - Phosphofructo- (1, 2) - Riboflavin - Shikimate - Thymidine - NAD+ - Glycerol - Pantothenate - Mevalonate - Pyruvate - Deoxycytidine - PFP - Diacylglycerol - Bruton's tyrosine - Phosphoinositide 3 (Class I PI 3, Class II PI 3) - Sphingosine 2.7.2 - COOH acceptor Phosphoglycerate - Aspartate 2.7.3 - N acceptor Creatine 2.7.4 - PO4 acceptor Phosphomevalonate - Adenylate - Nucleoside-diphosphate 2.7.6 - P2O7 Ribose-phosphate diphosphokinase - Thiamine pyrophosphokinase 2.7.7 - nucleotidyl- Integrase - PNPase - Polymerase - RNase PH - UDP-glucose pyrophosphorylase - Galactose-1-phosphate uridylyltransferase -Terminal deoxynucleotidyl transferase - RNA replicase - Reverse transcriptase (Telomerase) - Transposase 2.7.8 - other phos. N-acetylglucosamine-1-phosphate transferase 2.7.10-11 - protein Tyrosine - Serine/threonine-specific

v • d • e Transferase: polymerases (EC 2.7.7) DNA polymerase DNA polymerase I - DNA polymerase II - DNA polymerase III holoenzyme - DNA nucleotidylexotransferase RNA polymerase RNA polymerase I - RNA polymerase II - RNA polymerase III - primase

v • d • e DNA replication Origin of replication/Ori/Replicon - DNA clamp - Okazaki fragment - Replication fork (Lagging and leading strands) - Single-strand binding protein - Primer - Processivity - Klenow fragment Pre-replication complex: Helicase (dnaA, dnaB, T7) - Primase (dnaG) - DNA polymerase III holoenzyme (dnaQ) DNA ligase - Telomerase - Topoisomerase