Type III enzymes belong to the beta-subfamily of N6 adenine methyltransferases, containing the nine motifs that characterise this family, including motif I, the AdoMet binding pocket (FXGXG), and motif IV, the catalytic region (S/D/N (PP) Y/F).
Os encimas de tipo III pertencen á subfamilia beta de N6 adenina metiltransferases, que conteñen os nove motivos que caracterizan esta familia, incluíndo o motivo I, o peto de unión para a AdoMet (FXGXG), e o motivo IV, a rexión catalítica (S/D/N (PP) Y/F).