Formation of conjugated Δ11Δ13‐double bonds by Δ12‐linoleic acid (1,4)‐acyl‐lipid‐desaturase in pomegranate seeds

By E. Hornung, C. Pernstich, I. Feussner. 2002

90 citations recorded by the source corpus.

For the biosynthesis of punicic acid (18:3Δ9Z,11E,13Z) a (11,14)-linoleoyl desaturase activity has been proposed. To isolate this acyl-lipid-desaturase, PCR-based cloning was used. This approach resulted in the isolation of two complete cDNAs. The first isolated full-length cDNA harbors a sequence of 1350 bp encoding a protein of 395 amino acids. The second cDNA was 1415 bp long encoding a protein of 387 amino acids. For functional identification proteins encoded by the cDNAs were expressed in Saccharomyces cerevisiae, and formation of newly formed fatty acids was analyzed by gas chromatography-free induction decay (GC-FID) and GC/MS. The expression of the heterologous enzymes resulted in the first case in a significant amount of linoleic acid and in the second case, after linoleic acid supplementation, in formation of punicic acid. The results presented here identify one cDNA coding for a classical Δ12-acyl-lipid-desaturase. The other one codes for a new type of (1,4)-acyl-lipid-desaturase that converts a cis double bond located in the Δ12-position of linoleic acid or γ-linolenic acid, but not in α-linolenic acid, into a conjugated cis–trans double bond system.

Subfields: Biochemistry, Molecular Biology, Surgery

View Paper: https://www.semanticscholar.org/paper/c9472c7d09d6fb05d3281f32e15f0a41d3cd9671