Docosapentaenoic acid (DPA) designates any straight open chainpolyunsaturated fatty acid (PUFA) which contains 22 carbons and 5 double bonds. DPA is primarily used to designate two isomers, all-cis-4,7,10,13,16-docosapentaenoic acid (i.e. 4Z,7Z,10Z,13Z,16Z-docosapentaenoic acid) and all-cis-7,10,13,16,19-docosapentaenoic acid (i.e. 7Z,10Z,13Z,16Z,19Z-docosapentaenoic acid). They are also commonly termed n-6 DPA and n-3 DPA, respectively; these designations describe the position of the double bond being 6 or 3 carbons closest to the (omega) carbon at the methyl end of the molecule and is based on the biologically important difference that n-6 and n-3 PUFA are separate PUFA classes, i.e. the omega-6 fatty acids and omega-3 fatty acids, respectively. Mammals, including humans, can not interconvert these two classes and therefore must obtain dietary essential PUFA fatty acids from both classes in order to maintain normal health (see essential fatty acids).[1][2]
The two isomers osbond acid and clupanodonic acid have the same number of double bonds, but on different positions along the chain, so they are regioisomers.
n-6 DPA is an ω-6 fatty acid with the trivial name osbond acid. It is formed in two steps from eicosatetraenoic acid (5,8,11,14-20:4n-6 or arachidonic acid, AA). Arachidonic acid is elongated to docosatetraenoic acid (7,10,13,16-22:4n-6 or adrenic acid, AdA), which in turn is converted by Δ4-desaturase to osbond acid.[3]
n-3 DPA is an n-3 fatty acid with the trivial name clupanodonic acid. It is an intermediate compound between eicosapentaenoic acid (EPA 5,8,11,14,17-20:5n-3 or timnodonic acid) and docosahexaenoic acid (DHA 4,7,10,13,16,19-22:6n-3 or cervonic acid) in the metabolic pathway of DHA in eucaryotes. Eicosapentaenoic acid is elongated to clupanodonic acid, which in turn is converted by Δ4-desaturase to docosahexaenoic acid 22:6n-3 (see Docosahexaenoic acid § Biosynthesis).
Docosapentaenoic acid (DPA) is an n-3 fatty acid that is structurally similar to eicosapentaenoic acid (EPA) with the same number of double bonds, but two more carbon chain units.[4]
Salmon, red (sockeye), filets with skin, smoked (Alaska Native) 0.335 g in 1 filet (108 g)
Fish, salmon, Atlantic, farmed, raw 0.334 g in 3 oz (85 g)
Beef, variety meats and by-products, brain, cooked, simmered 0.326 g in 3 oz (85 g)
Seal meat and human breast milk are rich in DPA.[4]
Functions
Clupanodonic acid, an omega-3 fatty acid, along with its metabolite DHA and other long chain omega-3 fatty acids, is under study to determine properties of omega-3 fats in humans, such as in inflammation mechanisms.[6]