Activity of human Delta 5 and Delta 6 desaturases on multiple n-3 and n-6 polyunsaturated fatty acids

Yeast co-expressing human elongase and desaturase genes were used to invest igate whether the same desaturase gene encodes an enzyme able to desaturate n-3 and n-6 fatty acids with the same or different carbon chain length. Th e results clearly demonstrated that a single human Delta5 desaturase is act ive on 20:3n-6 and 20:4n-3. Endogenous Delta6 desaturase substrates were ge nerated by providing to the yeast radiolabelled 20:4n-6 or 20:5n-3 which, t hrough two sequential elongations, produced 24:4n-6 and 24:5n-3, respective ly. Overall, our data suggest that a single human Delta6 desaturase is acti ve on 18:2n-6, 18:3n-3, 24:4n-6 and 24:5n-3. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies .