Two types of alcohol dehydrogenase from Perilla can form citral and perillaldehyde

Two types of alcohol dehydrogenase that participate in the biosynthesis of oil components of Perilla were isolated. Both of these enzymes were expressed in all strains regardless of oil type. •Two types of alcohol dehydrogenase, AKR and GeDH, were cloned from Perilla.•AKR and GeDH converted primary alcohols into aldehydes by using NADP+.•AKR and GeDH reduced primary aldehydes to alcohols by using NADPH.•Sequential enzymatic reactions from GDP to citral via geraniol were performed in vitro.•Both AKR and GeDH were found in Perilla regardless of oil type. Studies on the biosynthesis of oil compounds in Perilla will help in understanding regulatory systems of secondary metabolites and in elucidating reaction mechanisms for natural product synthesis. In this study, two types of alcohol dehydrogenases, an aldo–keto reductase (AKR) and a geraniol dehydrogenase (GeDH), which are thought to participate in the biosynthesis of perilla essential oil components, such as citral and perillaldehyde, were isolated from three pure lines of perilla. These enzymes shared high amino acid sequence identity within the genus Perilla, and were expressed regardless of oil type. The overall reaction from geranyl diphosphate to citral was performed in vitro using geraniol synthase and GeDH to form a large proportion of citral and relatively little geraniol as reaction products. The biosynthetic pathway from geranyl diphosphate to citral, the main compound of citral-type perilla essential oil, was established in this study.