All three acyl moieties of trilinolein are efficiently oxygenated by recombinant His-tagged lipid body lipoxygenase in vitro.
Recently, we 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 His-tagged 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.
Institut für Pflanzenbiochemie, Halle, Germany. ifeussne@ipb.uni-halle.de
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Feussner
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Bachmann
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Höhne
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Kindl
D002846:Chromatography, Affinity; D018076:DNA, Complementary; D006639:Histidine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008084:Lipoxygenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013025:Glycine max / Q000201:enzymology; D013379:Substrate Specificity; D014280:Triglycerides / Q000378:metabolism*
D018076:DNA, Complementary; D011994:Recombinant Proteins; D014280:Triglycerides; D006639:Histidine; D008084:Lipoxygenase; D010100:Oxygen; C009564:trilinolein