Controls the night/day rhythm of melatonin production in the pineal gland. Catalyzes the N-acetylation of serotonin into N-acetylserotonin, the penultimate step in the synthesis of melatonin.
Subcellular locations: Cytoplasm
Highly expressed in pineal gland and at lower levels in the retina. Weak expression in several brain regions and in the pituitary gland.