Which enzyme type is involved in repairing damaged DNA caused by oxidative stress?

• A. Kinase
• B. Ligase
• C. Ogg1
• D. Transferase

Answer: (C)

The enzyme involved in repairing damaged DNA caused by oxidative stress is Ogg1, which stands for 8-oxoguanine DNA glycosylase 1. This enzyme specifically recognizes and removes oxidatively damaged guanine bases that can form as a result of oxidative stress. The presence of 8-oxoguanine in DNA can lead to mutations if not repaired, as it can pair incorrectly during DNA replication, potentially resulting in misincorporation of adenine opposite it.

Ogg1 functions through a process called base excision repair (BER), where it cleaves the glycosidic bond between the damaged base and the DNA backbone, allowing for the subsequent removal and replacement of the damaged nucleotide. This process is crucial for maintaining the integrity of the genetic material in cells exposed to oxidative agents.

Other enzyme types mentioned, such as kinases, ligases, and transferases, play different roles in cellular processes. Kinases are primarily involved in adding phosphate groups to substrates, ligases join two large molecules by forming new chemical bonds, and transferases transfer functional groups from one molecule to another. However, none of these categories play a direct role in the specific repair of oxidative DNA damage, making Ogg1 essential for this repair