 It is closest in sequence to glycine-N-methyl transferase (GNMT).It also shares many structural properties like the shape of the folding lip with catechol-O-methyl transferase (COMT), though it shares less sequence identity.Several features of the structure like this folding lip suggest that PNMT is a recent adaptation to the catecholamine synthesizing enzyme family, evolving later than COMT, but before other methyltransferases like GNMT.