Requires iron(II) and ascorbate. The product spontaneously undergoes trans-cis isomerization and lactonization to form scopoletin, liberating CoA in the process. The enzymes from the plants Ruta graveolens and Ipomoea batatas also act on trans-4-coumaroyl-CoA. cf. EC 220.127.116.11, trans-4-coumaroyl-CoA 2-hydroxylase.
Molecular cloning and functional analysis of the ortho-hydroxylases of p-coumaroyl coenzyme A/feruloyl coenzyme A involved in formation of umbelliferone and scopoletin in sweet potato, Ipomoea batatas (L.) Lam.