AM Biologie Notes

Base Excision Repair System removes incorrect or damaged bases from DNA. The main target of base excision repair is nonbulky damage to bases. A group of enzymes called DNA glycosylases play the main role in this method.

Different alkylating agents like Mastard Gas, Ethylmethane Sulfonate, Methylmethane Sulfonate, Nitrosoguanine etc. add alkyl groups to many positions on all four bases of DNA causing DNA damage or DNA mutation. But such damages can be repaired by different types of DNA Alkyl Transferase enzymes. One such enzyme known as Methyl Guanine Methyl Transferase (MGMT) plays an important role that I have mentioned.