All three acyl moieties of trilinolein are efficiently oxygenated by recombinant His-tagged lipid body lipoxygenase is vitro

Recently, me found a 13-lipoxygenase in germinating cucumber cotyledons, which was located at the lipid body membrane. Based on its products formed mobilization of storage lipids seems to be initiated by this 13-lipoxygenase, For biochemical characterization its cDNA was expressed as Histagged protein, Active recombinant enzyme was obtained from low temperature cultivation of E, coli after affinity purification, It (i) exhibited an unchanged region specificity, and (ii) showed a pH optimum of 7.2 against trilinolein as substrate, We compared its ability to oxygenate trilinolein with the one of another 13-lipoxygenase, soybean lipoxygenase-1. At the pH optimum of soybean lipoxygenase-1 (9.0), trilinolein was oxygenated only to 28% of the amount converted by the lipid body lipoxygenase. Moreover, trilinolein oxygenation by soybean lipoxygenase-1 leads mainly to monohydroperoxy derivatives, whereas oxygenation by lipid body LOX leads to a trihydroperoxy derivative. (C) 1998 Federation of European Biochemical Societies.