Epicubenol synthase. Origin of the oxygen atom of a bacterial sesquiterpene alcohol

Incubation of epicubenol synthase with farnesyl pyrophosphate in the presence of 11.1 atom% H218O gave epicubenol (2) in which the hydroxyl oxygen atom was shown to be derived exclusively from water, as established by GC-selected ion monitoring MS of the derived TMS-epicubenol derivative (15). Scheme 1.