Trans,cis-2,6-Nonadienal is a fatty acid derivative with an unsaturated 2,6-nonadiene structure. It is an inhibitor of the enzyme fatty acid synthase, which catalyzes the formation of long-chain polyunsaturated fatty acids. Trans,cis-2,6-Nonadienal has been shown to inhibit v79 cells and ester compounds that are used in analytical methods for measuring fatty acids. It is also able to inhibit lysine residues and it can be used as a reactive antioxidant system in mammalian cells. Trans,cis-2,6-Nonadienal has shown a profile of activities that includes inhibition at multiple endpoints involving noncompetitive inhibition as well as antioxidant activity.