Fig 2: hPNMT activity. Human recombinant enzyme activity was detected by fluorescence in the presence of a vehicle (DMSO—basal PNMT activity) of LY78335 or FIN. Panel A: PNMT activity in the presence of a high-affinity inhibitor LY78335 (50 µM) or FIN (50 µM). The columns represent the mean ± SEM of duplicate reactions. Panel B: dose–response curve in the presence of a high-affinity inhibitor LY78335 (black rhombus; from 6.4 nM to 50 µM) or FIN (gray triangle; from 6.4 nM to 50 µM). The symbols represent the mean ± SEM of duplicate reactions.

Fig 3: PNMT enzymatic reaction and competitive inhibition hypothesis. The enzymatic reaction (panel A) catalyzed by PNMT is reported along with the 2D formula of FIN (panel B). Norepinephrine and S-adenosyl-l-methionine (panel C—PDB ID: 3HCD) and FIN (panel D—PDB ID: 4MIK) within their corresponding binding sites in the same PNMT region are also shown, as obtained by X-ray diffraction and SPILLO-PBSS calculation, respectively (drawings rendered using VMD31).