Enantioselective oxidation of thiafatty acids by an algal Delta 12-desaturase

The whole-cell Chlorella vulgaris (211/8 K) system allows us to use thiaste arate methyl esters as a mechanistic probe of the Delta 12-desaturation pro cess. The 6-, 7-, 12- and 13-thiastearates are converted intracellularly to the corresponding Delta9-desaturated products, which can then be processed by the Delta 12-desaturase. The 6- and 7-thiaoleoyl are then desaturated r espectively to the 6- and 7-thialinoleoyl products; the 12- and 13-thiaolea tes are oxidised to the corresponding sulfoxides with a high enantioselecti vity (ee greater than or equal to 90%), confirming the oxygenase activity o f the Delta 12-desaturase with appropriately modified substrates. (C) 2001 Elsevier Science B.V. All rights reserved.