Repair of alkylated guanine in DNA by stoichiometrically transferring the alkyl group at the O-6 position to a cysteine residue in the enzyme. This is a suicide reaction: the enzyme is irreversibly inactivated. Can also repair O-4-methylthymine.
The methylated ADA protein acts as a positive regulator of its own synthesis, as well as that of other proteins. The transcription-activating function of the ADA protein resides in its N-terminus. It activates the transcription of alkA, alkB and aidB.
Synonyms: Regulatory protein of adaptative response
Gene name: ada