In enzymology, an isopiperitenone Delta-isomerase () is an enzyme that catalyzes the chemical reaction
Hence, this enzyme has one substrate, isopiperitenone, and one product, piperitenone.
This enzyme belongs to the family of isomerases, specifically those intramolecular oxidoreductases transposing C=C bonds. The systematic name of this enzyme class is isopiperitenone Delta8-Delta4-isomerase.