In humans, O6-alkylguanine DNA alkyltransferase preferentially removes alkyl groups from O6-alkyl guanine rather than from O6–alkyl thymine.
Nos humanos a O6-alquilguanina ADN alquiltransferase preferencialmente retira os grupos alquilo da O6-alquilguanina en vez de da O6–alquiltimina.