FIGURE 1.

Terpene synthase catalyzed biosynthesis of monoterpenols from geranyl diphosphate (GPP; adapted from Degenhardt et al., 2009). Terpene synthases cleave the diphosphate group from the substrate, which results in the formation of a carbocation intermediate that can further rearrange. The reaction can be terminated by proton abstraction, which yields hydrocarbon monoterpenes (here illustrated by myrcene and β-ocimene), or by addition of water, which yields monoterpene alcohols, or monoterpenols. The route leading to monoterpenols is highlighted in green. (E)-8- and (Z)-8-linalool oxidized derivatives are also referred to as 8- and 9-linalool derivatives, respectively. In some older papers, (E)-8-hydroxygeraniol is referred to as 10-hydroxygeraniol. GPP, geranyl diphosphate; LPP, linalyl diphosphate.