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Sesamin is a potent and specific inhibitor of Δ5 desaturase in polyunsaturated fatty acid biosynthesis
Author(s) -
Shimizu Sakayu,
Akimoto Kengo,
Shinmen Yoshifumi,
Kawashima Hiroshi,
Sugano Michihiro,
Yamada Hideaki
Publication year - 1991
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02536595
Subject(s) - sesamin , polyunsaturated fatty acid , arachidonic acid , biochemistry , biosynthesis , fatty acid desaturase , chemistry , lignan , fatty acid , linoleic acid , biology , enzyme , food science , stereochemistry
Incubation with sesame oil increases the mycelial dihomo‐γ‐linolenic acid content of an arachidonic acid‐producing fungus, Mortierella alpina , but decreases its arachidonic acid content [Shimizu, S., K. Akimoto, H. Kawashima, Y. Shinmen and H. Yamada (1989) J. Am. Oil Chem. Soc. 66 , 237–241]. The factor causing these effects was isolated and identified to be (+)‐sesamin. The results obtained in experiments with both a cell‐free extract of the fungus and with rat liver microsomes demonstrated that (+)‐sesamin specifically inhibits Δ5 desaturase at low concentrations, but does not inhibit Δ6, Δ9 and Δ12 desaturases. Kinetic analysis showed that (+)‐sesamin is a noncompetitive inhibitor (K i for rat liver Δ5 desaturase, 155 μM). (+)‐Sesamolin, (+)‐sesaminol and (+)‐episesamin, also inhibited only Δ5 desaturases of the fungus and liver. These results demonstrate that (+)‐sesamin and related lignan compounds present in sesame seeds or its oil are specific inhibitors of Δ5 desaturase in polyunsaturated fatty acid biosynthesis in both microorganisms and animals.