The primary chemical reaction that is catalyzed by aralkylamine N-acetyltransferase uses two substrates, acetyl-CoA and serotonin.
AANAT catalyzes the transfer of the acetyl group of Acetyl-CoA to the primary amine of serotonin, thereby producing CoA and N-acetylserotonin.
In humans, other endogenous substrates of the enzyme include specific trace amine neuromodulators, namely phenethylamine, tyramine, and tryptamine, in turn forming N-acetylphenethylamine, N-acetyltyramine, and N-acetyltryptamine.

In the biosynthesis of melatonin, N-acetylserotonin is further methylated by another enzyme, N-acetylserotonin O-methyltransferase (ASMT) to generate melatonin.
The N-acetyltransferase reaction has been suggested to be the rate-determining step, and thus Serotonin N-acetyltransferase has emerged as a target for inhibitor design (see below).

AANAT obeys an ordered ternary-complex mechanism.
The substrates bind sequentially (ordered) with acetyl-CoA binding to the free enzyme followed by the binding of serotonin to form the ternary complex.
After the transfer of the acetyl group has occurred, the products are orderly released with N-acetyl-serotonin first and CoA last.
The primary chemical reaction that is catalyzed by aralkylamine N-acetyltransferase uses two substrates, acetyl-CoA and serotonin. AANAT catalyzes the transfer of the acetyl group of Acetyl-CoA to the primary amine of serotonin, thereby producing CoA and N-acetylserotonin. In humans, other endogenous substrates of the enzyme include specific trace amine neuromodulators, namely phenethylamine, tyramine, and tryptamine, in turn forming N-acetylphenethylamine, N-acetyltyramine, and N-acetyltryptamine.
In the biosynthesis of melatonin, N-acetylserotonin is further methylated by another enzyme, N-acetylserotonin O-methyltransferase (ASMT) to generate melatonin. The N-acetyltransferase reaction has been suggested to be the rate-determining step, and thus Serotonin N-acetyltransferase has emerged as a target for inhibitor design (see below).
AANAT obeys an ordered ternary-complex mechanism. The substrates bind sequentially (ordered) with acetyl-CoA binding to the free enzyme followed by the binding of serotonin to form the ternary complex. After the transfer of the acetyl group has occurred, the products are orderly released with N-acetyl-serotonin first and CoA last.
Aralkylamine N-acetyltransferase