3,4-dihydroxy-5-methoxyphenethylamine + S-adenosyl-L-methionine <=> N-methyl-3,4-dihydroxy-5-methoxyphenethylamine + S-adenosyl-L-homocysteine + H(+)
3,4-dihydroxy-5-methoxyphenethylamine + s-adenosyl-l-methionine <=> n-methyl-3,4-dihydroxy-5-methoxyphenethylamine + s-adenosyl-l-homocysteine + h(+)