Geraniol dehydrogenase

In the classical procedures W, the 5-T or D-labeled mevalonate is converted enzymatically to farnesol, which is then oxidized to famesal by liver alcohol dehydrogenase. This enzyme transfers the pro-R hydrogen of C—1 of ethanol or geraniol (or farnesol) to the 4 pro R position of the nicotinamide ring of NAD. 

Working with orange juice vesicles. Potty and Bruemmer have isolated an enzyme, geraniol dehydrogenase, that maintains the equilibrium between aldehyde and alcohol. The presence of a second enzyme that saturates one of the double bonds in this system to citronellal and citronellol is inferred. The same authors have also demonstrated the presence of enzymes which convert mevalonate to linalyl pyrophosphate, suggesting that citrus fruits synthesise terpenoids from mevalonate by this route. 

Alcohol dehydrogenases catalyse the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively. Typical primary alcohols acting as substrate are ethanol, benzylic alcohol, phenylethanol, geraniol and retinol. Methanol is a poor substrate and is only slowly oxidized at high concentrations. Secondary alcohols are more difficult to oxidize, while tertiary alcohols are resistant towards dehydrogenation. This explains in part the greater... 

The potential applications of oxidoreductases in industry are numerous. Alcohol dehydrogenases are useful in stereospecific synthesis and production of high-cost compounds such as cyclic ethers (see below), and have also been used in the production of flavour aldehydes e.g. geraniol [94]. With mesophilic enzymes, however, limitations due to narrow specificity, instability to heat and organic solvents and loss of activity on immobilization have been incurred. The use of these enzymes from thermophilic sources in inunobilized and continuous reactor systems (including biosensors) has also been proposed for the regeneration of... 

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