1. DNA Repair Mechanism
Dr. Madhura Mukadam
Associate Professor,
Dept. of Zoology,
Gogate Jogalekar College, Ratnagiri
Dt. 13.01.2018
2.
3. • Directly to revert the damage (Single step repair system)
• To remove the damaged section of DNA and fill it with new
DNA
• Single step repair system include repair mediated by
enzyme ligase, photolyase and methyl transferase etc.
• Ligase- single strand breaks are simply joined.
• Photolyase- recognizes pyrimidine dimer and activates the
enzynme to break the bond between two pyrimidines and
restores them.
• Methyl transferase- suicidal enzyme. This enzyme is
induced when cell is exposed to alkylating agents. These
are refered as multistep repair system and involve
removing damged part of DNA and replacing it with new
undamaged DNA.
