Stereochemistry in the reduction of the CC bond of verbenone with a reductase from the cultured cells of Nicotiana tabacum

Reduction of the CC bond of verbenone by a reductase from the cultured cells of Nicotiana tabacuminvolves syn-addition of the hydrogen atom to the re-reface of the double bond; the hydrogen atoms participating in the reduction at C-2 and C-3 of verbenone originate from the pro-4Shydrogen of NADPH and the medium, respectively.