Serotonin biosynthesis pathway (null)

The **serotonin biosynthesis pathway**, also known as the tryptophan-serotonin pathway, is a metabolic sequence responsible for producing the neurotransmitter **serotonin (5-hydroxytryptamine; 5-HT)** from the essential amino acid L-tryptophan. The process involves two main enzymatic steps in animals: 1. **Hydroxylation:** L-Tryptophan is converted into **5-hydroxytryptophan**, catalyzed by *tryptophan hydroxylase*—the rate-limiting enzyme. 2. **Decarboxylation:** *Aromatic amino acid decarboxylase* then converts this intermediate into **serotonin.[1][2]** Serotonin can subsequently be metabolized into melatonin via N-acetyltransferases and O-methyltransferases.[2] The availability of tryptophan and activity/expression levels of these enzymes regulate overall production. While individual proteins within this cascade—such as tryptophan hydroxylase and monoamine oxidases—are considered therapeutic targets for various neuropsychiatric conditions and cancer,[6][8] the entire "pathway" itself is not a single molecular target but rather a collection of biochemical reactions involving multiple distinct proteins. Therefore: The term "Serotonin biosynthesis pathway" refers broadly to a series of enzymatic steps rather than one discrete molecule/receptor/protein. It should not be classified as an individual therapeutic target; instead, its constituent enzymes are valid targets. If you need structured information about specific components such as "Tryptophan hydroxylase," please specify that enzyme/protein directly.

Other names

Serotonin synthesis pathway5-HT biosynthesis pathwayTryptophan-serotonin pathway

Drugs act on specific enzymes or transporters in the serotonin system: Inhibition of monoamine oxidase to prevent serotonin breakdown (MAOIs); Inhibition of aromatic amino acid decarboxylase to reduce peripheral conversion of precursors (carbidopa/benserazide); Inhibition of serotonin reuptake transporter to increase synaptic levels of serotonin (SSRIs/TCAs)