Divinyl ether synthase from garlic (Allium sativum L.) bulbs: sub-cellular localization and substrate regio-and stereospecificity.

Sub-cellular localization and some properties of 13-hydroperoxide-specific divinyl ether synthase from garlic bulbs were studied. Sub-cellular fractions from garlic bulbs were incubated with [1-(14)C](9Z,11E,13S)-13-hydroperoxy-9,11-octadecadienoic acid (13-HPOD). The predominant part of divinyl ether synthase activity from garlic bulbs was found in the microsomal fraction. The enzyme utilizes 13(S)-HPOD as its preferential substrate. Other hydroperoxides, including 9(S)-HPOD, gave much poorer yields of divinyl ethers. Unreacted hydroperoxide after incubation of 13(R,S)-HPOD with enzyme was composed of up to 94% 13(R)-HPOD. Thus, divinyl ether synthase possesses stereoselectivity, utilizing preferentially the (S)-enantiomer.