PNMT-IN-1 (inhibtor 4) is a specific inhibitor of phenylethanolamine N-methyltransferas ( PNMT ) with a K i value of 1.2 nM and a IC 50 value of 81 nM. PNMT-IN-1 also inhibits the vitality of DNMT1 and DNMT3b, with the IC 50 value of 61 μM and 17 μM, respectively, and has an antagonistic effect on epinephrine.PNMT-IN-1 (inhibtor 4 ) is a second generation inhibitor.