R Subfamilies

CYP71D subfamily is also large and currently comprises a total of 22 members from 10 different plant species. At present, the catalytic properties of five CYP71D enzymes have been determined and the enzymes assigned to specific steps in indole alkaloid, sequiterpenoid, cyclic terpenoid, and flavonoid synthesis. Accordingly, enzymes belonging to the CYP71D subfamily do not necessarily share similar functional characteristics. 

The third fimctionally characterized member of the CYP71D subfamily is CYP71D9. This enzyme has been identified in soybean as a flavonoid 6-hydroxylase. It was demonstrated that hydroxylation of carbon atom-6 of the A-ring precedes 1,2-aryl migration to produce isoflavonoids as described in Section 5.4.  

Regiospecific hydroxylation of the monoter-pene (—)-46 -limonene at the C-3 or C-6-allylic positions to yield (—)-menthol (peppermint) or (—)-carvone (spearmint), respectively, is accomplished by the last two functionally characterized CYP71DS, the CYP71D13 and CYP79D18 found in commercial mint species (Mentha sp.) . 

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