Polymerase

From Wikipedia, the free encyclopedia

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 most well-known function of a polymerase is the catalysis of production of new DNA or RNA from 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 hydrogen-bond them to complementary nucleotides that are on the template, or sense strand.

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, pronounced "tack") (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] External links

• Flash animation at McGraw-Hill genetics-Dna%20Replication

[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