 Hydride is then transferred from the beta-carbon of the substrate to the N(5) of the FAD, yielding the 2e−-reduced form of FAD.Thus, this allows for the decarboxylation of glutaconyl-CoA, an enzyme-bound intermediate, by breaking the Cγ-Cδ bond, resulting in formation of a dienolate anion, a proton, and CO2.The dienolate intermediate is protonated, resulting in crotonyl-CoA and a release of products from the active site.