Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In enzymology, a vinylacetyl-CoA Delta-isomerase (EC 5.3.3.3) is an enzyme that catalyzes the chemical reaction (vinylacetyl-CoA rightleftharpoons crotonyl-CoA). Hence, this enzyme has one substrate, vinylacetyl-CoA, and one product, crotonyl-CoA. This enzyme belongs to the family of isomerases, specifically those intramolecular oxidoreductases transposing C=C bonds. The systematic name of this enzyme class is vinylacetyl-CoA Delta3-Delta2-isomerase. Other names in common use include vinylacetyl coenzyme A Delta-isomerase, vinylacetyl coenzyme A isomerase, and Delta3-cis-Delta2-trans-enoyl-CoA isomerase. This enzyme participates in butanoate metabolism.