Krügener Sven, Krings Ulrich, Zorn Holger, Berger Ralf G
Zentrum für Angewandte Chemie der Leibniz Universität Hannover, Institut für Lebensmittelchemie, Wunstorfer Str. 14, D-30453 Hannover, Germany.
Bioresour Technol. 2010 Jan;101(2):457-62. doi: 10.1016/j.biortech.2009.08.087. Epub 2009 Sep 17.
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-octahydro-naphthalen-2(R)-yl-hydroperoxide. Chemical reduction of the biotransformation products yielded a tertiary alcohol identified as 2(R)-Isopropenyl-8(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.
利用可食用蘑菇美味侧耳的冻干物，实现了倍半萜（+）-瓦伦烯向葡萄柚风味化合物（+）-诺卡酮的选择性高效烯丙基氧化。通过鉴定中间体（+）-瓦伦烯衍生的氢过氧化物，阐明了催化反应序列。氢过氧化物的特异性染色使得半制备分离出两种仲（+）-瓦伦烯氢过氧化物，即6（R）-异丙烯基-4（R），4a（S）-二甲基-2,3,4,4a,5,6,7,8-八氢萘-4（S）-基氢过氧化物和6（R）-异丙烯基-4（R），4a（S）-二甲基-2,3,4,4a,5,6,7,8-八氢萘-2（R）-基氢过氧化物。生物转化产物的化学还原得到一种叔醇，鉴定为2（R）-异丙烯基-8（R），8a（S）-二甲基-1,3,4,7,8,8a-六氢-2H-萘-4a（R）-醇。这表明（+）-瓦伦烯通过仲氢过氧化物和叔氢过氧化物进行脂氧合酶型氧化，并证实了先前从氨基酸测序获得的关键酶的同源性数据。
