Amines that are neurotransmitters and hormones can be derived from amino acids. Dopamine and serotonin are 2 such neurotransmitters. Which amino acids do they come from?

1 Answer
Jul 16, 2016


They come from tyrosine and tryptophan, respectively.


Both are formed by enzymatically controlled hydroxylation and decarboxylation reactions.


Dopamine is formed by the metabolism of tyrosine.

#"Tyrosine" → "L-DOPA" → "Dopamine"#

The enzyme tyrosine hydroxylase first hydroxylates tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA).

In a second step, the enzyme L-DOPA decarboxylase decarboxylates L-DOPA to form dopamine.


Serotonin is formed by the metabolism of tryptophan.

#"Tryptophan" → "5-hydroxytryptophan" → "serotonin"#

In the first step, the enzyme tryptophan hydroxylase hydroxylates tryptophan to form 5-hydroxy tryptophan (5-HTP).

In a second step, the enzyme aromatic L-amino acid decarboxylase decarboxylates 5-HTP to form serotonin.