Assertion: l tryptophan | /r/CapableOf | serve as precursor
Facets:
value: to serotonin
type: TRANSITIVE-OBJECT
value: in the body
type: LOCATION
Source sentences:
text: L-Tryptophan is an essential amino acid that serves as a precursor to the important neurotransmitter serotonin.
text: In the body it functions as a precursor to serotonin, a neurotransmitter.