although both wild-type and adaptation-deficient ( ada ) mutants of e. coli contained low but comparable numbers ( from 13 to 60 ) of the enzyme molecules per cell , adaptation treatment caused a significant increase of the enzyme in the wild type but not in the ada mutants , suggesting that the ada mutation is in a regulatory locus and not in the structural gene for the methyltransferase .
C0007634
cell
C1708726
locus