N-acetylserotonin + S-adenosyl-L-methionine = melatonin + S-adenosyl-L-homocysteine + H(+)
n-acetylserotonin + s-adenosyl-l-methionine = melatonin + s-adenosyl-l-homocysteine + h(+)
"acetylserotonin O-methyltransferase"
"acetylserotonin o-methyltransferase"