In enzymology, a neoxanthin synthase (EC 5.3.99.9) is an enzyme that catalyzes the chemical reaction: Hence, this enzyme has one substrate, violaxanthin, and one product, neoxanthin.
This enzyme belongs to the family of isomerases, specifically a class of other intramolecular oxidoreductases.
The systematic name of this enzyme class is violaxanthin---neoxanthin isomerase (epoxide-opening).
This enzyme is also called NSY.
This enzyme participates in carotenoid biosynthesis - general.