Redox interconversion of geraniol and nerol in Rosa damascena

Use of ¹⁴C, ³H-labelled precursors revealed that flowerheads of Rosa damascena converted geraniol (3,7-dimethylocta-trans-2,6-dien-1-ol) into nerol (the corresponding cis-isomer) with loss of the pro-(1S) hydrogen, whereas the reverse isomerization involved loss of the pro-(1R) atom. The inference that the interconversion proceeded by redox reactions with the formation of the corresponding aldehydes was supported by the preparation of cell-free extracts from R. damascena and R. dilecta that sustained such processes. These reactions were NADP⁺-NADPH dependent and had pH optima at 7.0 and 9.0, respectively.