Divinyl ether synthases (DESs) are the enzymes occurring in numerous plant species and catalysing the dehydration of fatty acid hydroperoxides to divinyl ether oxylipins, playing self-defensive and antipathogenic roles in plants. Previously, the DES activities and divinyl ethers were detected in some monocotyledonous plants, including the asparagus (Asparagus officinalis L.). The cloning of the open reading frame of the CYP74H2 gene of asparagus and catalytic properties of the recombinant CYP74H2 protein are described in the present work. The CYP74H2 utilized the 13(S)-hydroperoxide of linoleic acid (13(S)-HPOD) as a preferred substrate and specifically converted it to the divinyl ether, (9Z,11Z)-12-[(1ʹE)-hexenyloxy]-9,11-dodecadienoic acid, (11Z)-etheroleic acid. The second most efficient substrate after the 13(S)-HPOD was the 9(S)-hydroperoxide of α−linolenic acid (9(S)-HPOT), which was converted to the previously undescribed product, (1ʹZ)-colnelenic acid. The 13(S)-hydroperoxide of α−linolenic acid (13(S)-HPOT) and 9(S)-hydroperoxide of linoleic acid (9(S)-HPOD) were less efficient substrates for CYP74H2. Both 13(S)-HPOT and 9(S)-HPOD were transformed to divinyl ethers, (11Z)-etherolenic and (1ʹZ)-colneleic acids, respectively. The CYP74H2 is a second cloned monocotyledonous DES after the garlic CYP74H1 and the first DES biosynthesizing the (1ʹZ)-colneleic and (1ʹZ)-colnelenic acids.

二乙烯基醚合酶 (DESs) 是存在于许多植物物种中的酶，它催化脂肪酸氢过氧化物脱水为二乙烯基醚氧化脂，在植物中发挥自我防御和抗病原作用。以前，在一些单子叶植物，包括芦笋（Asparagus officinalis L.）中检测到 DES 活性和二乙烯基醚。本文介绍了芦笋CYP74H2基因开放阅读框的克隆和重组CYP74H2蛋白的催化特性。CYP74H2 利用亚油酸的 13( S )-过氧化氢 (13( S )-HPOD) 作为优选的底物，并将其专门转化为二乙烯基醚 (9 Z ,11 Z)-12-[( 1ʹE)-己烯氧基]-9,11-十二碳二烯酸，(11 Z ) -醚油酸。继 13( S )-HPOD之后第二个最有效的底物是 α-亚麻酸 (9( S )-HPOT) 的 9( S )-氢过氧化物，它被转化为先前未描述的产物，( 1ʹZ )-colnelenic酸。α-亚麻酸的 13( S )-氢过氧化物 (13( S )-HPOT) 和亚油酸的9( S )-氢过氧化物 (9( S )-HPOD) 对 CYP74H2 的底物效率较低。13( S )-HPOT 和 9( S )-HPOD 均转化为二乙烯基醚，( 11Z)-醚烯酸和 (1ʹ Z )-colneleic 酸。CYP74H2 是继大蒜 CYP74H1 之后第二个克隆的单子叶植物 DES 和第一个生物合成 ( 1ʹ Z )-colneleic 酸和 (1ʹ Z )-colnelenic 酸的 DES。