A dioxygenase of Pleurotus sapidus transforms (+)-valencene regio-specifically to (+)-nootkatone via a stereo-specific allylic hydroperoxidation

作者：Kruegener Sven; Krings Ulrich; Zorn Holger; Berger Ralf G^*

来源：Bioresource Technology, 2010, 101(2): 457-462.

DOI：10.1016/j.biortech.2009.08.087

• Pleurotus sapidus
• Valencene dioxygenase
• Nootkatone
• (+)-Valencene hydroperoxide

A selective and highly efficient allylic oxidation of the sesquiterpene (+)-valencene to the grapefruit flavour compound (+)-nootkatone was achieved with lyophilisate of the edible mushroom Pleurotus sapidus. The catalytic reaction sequence was elucidated through the identification of intermediate, (+)-valencene derived hydroperoxides. A specific staining of hydroperoxides allowed the semi-preparative isolation of two secondary (+)-valencene hydroperoxides, 6(R)-Isopropenyl-4(R),4a(S)-dimethyl-2,3,4,4a,5,6,7,8-octahydro-naphthalen-4(S)-yl-hydroperoxide and 6(R)-Isopropenyl-4(R),4a(S)-dimethyl-2,3,4,4a,5,6,7,8-8-octahydro-naphthalen-2(R)-yl-hydroperoxide. Chemical reduction of the biotransformation products yielded a tertiary alcohol identified as 2(R)-Isopropenyl-S(R),8a(S)-dimethyl-1,3,4,7,8,8a-hexahydro-2H-naphthalen-4a(R)-ol. This suggested a lipoxygenase-type oxidation of (+)-valencene via secondary and tertiary hydroperoxides and confirmed homology data of the key enzyme obtained previously from amino acid sequencing.

• 出版日期2010-1