Stereoselectivity of Abscisic Acid-oxygenase in Avocado Fruits

Abstract

The optically resolved (±)-dihydrophaseic acid (DPA) was achieved by using a commercially available chiral HPLC column. PA and DPA, which were isolated after feeding (±)-(RS)-[²H₆]-ABA to avocado fruits, were analyzed by the chiral HPLC method to examine the stereoselectivity of the oxygenase. Small peaks of the unnatural enantiomer could be observed in each case. The results show convincingly that (-)-(R)-ABA was converted to PA and DPA, although the extent of this conversion is very small in comparison with the conversion of (+)-(S)-ABA.