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Unformatted text preview: edina Jr. Page 6 of 7 Mutation & DNA Repair Mechanism REPAIR MECHANISMS
*Photoreactivating enzyme which recognizes thymine dimers and monomerizes it upon
absorption of visible light.
*DNA glycosylases recognize altered bases and catalyze its hydrolytic removal from
B. FREE-RADICAL SCAVENGERS / ANTI-OXIDANTS
*Glutathione and Metallothionein
*Enzymes such as superoxide dismutase, catalase, and peroxidases
*Vitamins such as Vitamins C, A and E (conjugated double bonds in their structures react
with free radicals)
C. DARK REPAIR MECHANISM
• Excision repair
-example: thymine dimers in one strand only • Post replication repair
-example: thymine dimers in 2 strands Isidro C. Medina Jr. Page 7 of 7 Mutation & DNA Repair Mechanism...
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