Canadian Medical Guide > Chemicals and Drugs > Enzymes and Coenzymes > Enzymes > DNA Repair Enzymes Terms and Definitions

DNA Repair Enzymes

Medical Definition:	Enzymes that are involved in the reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule, which contained damaged regions.
Guide Notes:	GEN; prefer specifics; coord with specific enzyme not treed here
CAS Number:	EC 6.5.1.-
Previously Indexed:	DNA Ligases (1978-2003)

DNA Repair Enzymes Categories.

	Deoxyribodipyrimidine Photo-Lyase - An enzyme that catalyzes the reactivation by light of UV-irradiated DNA. It breaks two carbon-carbon bonds in pyrimidine dimers in DNA. EC 4.1.99.3.
	DNA Glycosylases - A family of DNA repair enzymes that recognize damaged nucleotide bases and remove them by hydrolyzing the N-glycosidic bond that attaches them to the sugar backbone of the DNA molecule. The process called BASE EXCISION REPAIR can be completed by a DNA-(APURINIC OR APYRIMIDINIC SITE) LYASE which excises the remaining RIBOSE sugar from the DNA.
	DNA Ligases - Poly(deoxyribonucleotide):poly(deoxyribonucleotide)ligases. Enzymes that catalyze the joining of preformed deoxyribonucleotides in phosphodiester linkage during genetic processes during repair of a single-stranded break in duplex DNA. The class includes both EC 6.5.1.1 (ATP) and EC 6.5.1.2 (NAD).
	DNA-(Apurinic or Apyrimidinic Site) Lyase - A DNA repair enzyme that catalyses the excision of ribose residues at apurinic and apyrimidinic DNA sites that can result from the action of DNA GLYCOSYLASES. The enzyme catalyzes a beta-elimination reaction in which the C-O-P bond 3' to the apurinic or apyrimidinic site in DNA is broken, leaving a 3'-terminal unsaturated sugar and a product with a terminal 5'-phosphate. This enzyme was previously listed under EC 3.1.25.2.
	Polynucleotide 5'-Hydroxyl-Kinase - An enzyme that catalyzes the transfer of a phosphate group to the 5'-terminal hydroxyl groups of DNA and RNA. EC 2.7.1.78.

DNA Repair Enzymes Medical Definitions and Terms

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