Compared to other alleles, Cyp6a2Canton-S-2 substitutes a 'TGCG' quadrinucleotide with 'AG' in the 5' core promoter region. This region forms part of a canonical binding site for the Nrf2/Maf heterodimer.
Cyp6a2Canton-S-1 and Cyp6a2Canton-S-1 are two different Cyp6a2 alleles found in the wild type Canton-S strain.