Catalyzes the transmethylation of nonepinephrine (noradrenaline) to form epinephrine (adrenaline), using S-adenosyl-L-methionine as the methyl donor (PubMed:17698731). Other substrates include phenylethanolamine, octopamine and normetanephrine (By similarity). phenylethanolamine + S-adenosyl-L-methionine = H(+) + N-methylphenylethanolamine + S-adenosyl-L-homocysteine (R)-noradrenaline + S-adenosyl-L-methionine = (R)-adrenaline + H(+) + S-adenosyl-L-homocysteine (R)-normetanephrine + S-adenosyl-L-methionine = H(+) + N-methyl-(R)-normetanephrine + S-adenosyl-L-homocysteine (R)-octopamine + S-adenosyl-L-methionine = (R)-synephrine + H(+) + S-adenosyl-L-homocysteine Catecholamine biosynthesis; (R)-adrenaline biosynthesis; (R)-adrenaline from (R)-noradrenaline: step 1/1. Brain (pons and medulla oblongata), adrenal gland, retina and heart. In knockout (KO) mice, resting cardiovascular function, including blood pressure (BP), heart rate and cardiac output is the same as that in wild-type mice (PubMed:17698731). Significant difference, however, is observed in the BP response to exercise (PubMed:17698731). The relative diastolic wall thickness and the ratio of left ventricular posterior wall thickness (LVPW) to left ventricular internal dimension (LVID) are significantly increased in KO mice (PubMed:17698731). Belongs to the class I-like SAM-binding methyltransferase superfamily. NNMT/PNMT/TEMT family.