Motifs in the C-terminal region of the Penicillium chrysogenum ACV synthetase are essential for valine epimerization and processivity of tripeptide formation

► The EGHGRE motif in the epimerization domain of ACVS is essential for activity. ► None of the free thioesterases of P. chrysogenum can complement the ACVS activity. ► Expression of the ACVS thioesterase domain as a stand-alone unit restored activity.