A model system was defined consisting of the ribose-nicotinamide portion of NADP(H), and the thioester fraction of the crotonyl-CoA substrate. A preliminary transition struc-ture was sought using the autodE software at the PBE0/def2-SVP level of theory. This transition structure (TS) was optimized in vacuo at the M06-2X/def2-TZVP level using the software Gaussian 16. The presence of an imaginary frequency corresponding to the hydride transfer was verified. The reaction coordinate was followed in vacuo at the same level of theory, leading to configurations of the reactant (reduced nicotinamide configuration) and product (enolate-type configuration). The geometries of these endpoints plus the TS were extracted, and their energy evaluated using different methods and basis sets. For the density functionals, calculations with the D3 dispersion correction were also included.