serotonin + S-adenosyl-L-methionine <=> 5-methoxytryptamine + S-adenosyl-L-homocysteine + H(+)
serotonin + s-adenosyl-l-methionine <=> 5-methoxytryptamine + s-adenosyl-l-homocysteine + h(+)
serotonin + S-adenosyl-L-methionine <=> 5-methoxytryptamine + S-adenosyl-L-homocysteine + H(+)
serotonin + s-adenosyl-l-methionine <=> 5-methoxytryptamine + s-adenosyl-l-homocysteine + h(+)