Oleate desaturation by wild-type and mutant BnFAD2.A5 desaturases expressed in yeast. Fatty acid methyl esters were prepared from yeast lipids and analyzed using gas chromatography. (a) Yeast transformed with empty vector; (b) wild-type BnFAD2.A5; (c) P202L; (d) G232S; (e) G200R. Fatty acids are: 1, 16:0; 2, 16:1; 3, 16:2; 4, 18.0; 5, 18:1; 6, 18:2.