The biosynthetic pathway from linoleic acid to 1-octen-3-ol in has long been established, in which linoleic acid is converted to 10-hydroperoxide (10-HPOD) by deoxygenation, and 10-HPOD is subsequently cleaved to yield 1-octene-3-ol and 10-oxodecanoic acid. However, the corresponding enzymes have not been identified and cloned. In the present study, four putative genes involved in oxylipid biosynthesis, including one lipoxygenase gene named , two linoleate diol synthase genes named 1 and 2, and one hydroperoxide lyase gene named were retrieved from the genome by a homology search and cloned and expressed prokaryotically. LOX, LDS1, and LDS2 all exhibited fatty acid dioxygenase activity, catalyzing the conver... More
The biosynthetic pathway from linoleic acid to 1-octen-3-ol in has long been established, in which linoleic acid is converted to 10-hydroperoxide (10-HPOD) by deoxygenation, and 10-HPOD is subsequently cleaved to yield 1-octene-3-ol and 10-oxodecanoic acid. However, the corresponding enzymes have not been identified and cloned. In the present study, four putative genes involved in oxylipid biosynthesis, including one lipoxygenase gene named , two linoleate diol synthase genes named 1 and 2, and one hydroperoxide lyase gene named were retrieved from the genome by a homology search and cloned and expressed prokaryotically. LOX, LDS1, and LDS2 all exhibited fatty acid dioxygenase activity, catalyzing the conversion of linoleic acid to generate hydroperoxide, and HPL showed a cleaving hydroperoxide activity, as was determined by the KI-starch method. LOX and HPL catalyzed linoleic acid to 1-octen-3-ol with an optimum temperature of 35 °C and an optimum pH of 7.2, whereas LDS1, LDS2, and HPL catalyzed linoleic acid without 1-octen-3-ol. Reduced expression in antisense transformants was correlated with a decrease in the yield of 1-octen-3-ol. LOX and HPL were highly homologous to the sesquiterpene synthase Cop4 of and the yeast sterol C-22 desaturase, respectively. These results reveal that the enzymes for the oxidative cleavage of linoleic acid to synthesize 1-octen-3-ol in are the multifunctional fatty acid dioxygenase LOX and hydroperoxide lyase HPL.
