05 Mutations and DNA repair mechanism

Medina jr page 6 of 7 mutation dna repair mechanism

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Unformatted text preview: edina Jr. Page 6 of 7 Mutation & DNA Repair Mechanism REPAIR MECHANISMS A. ENZYMES Examples: *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 deoxyribose. B. FREE-RADICAL SCAVENGERS / ANTI-OXIDANTS Examples: *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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This document was uploaded on 02/27/2014.

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