TY - JOUR
T1 - In vitro oxygenation of soybean biomembranes by lipoxygenase-2
AU - Maccarrone, Mauro
AU - van Aarle, Peter G M
AU - Veldink, Gerrit A.
AU - Vliegenthart, Johannes F G
PY - 1994/2/23
Y1 - 1994/2/23
N2 - The ability of soybean lipoxygenases-1 and -2 to oxygenate biomembranes isolated from soybean seedlings has been investigated. Constituents of the lipid bilayer were analyzed by means of reversed phase and chiral phase high performance liquid chromatography, gas chromatography/mass spectrometry, high performance thin layer chromatography and uv spectroscopy. Evidence is presented that soybean lipoxygenase-2, at variance with the type-1 enzyme, oxygenates the esterified unsaturated fatty acid moieties in biomembranes, whereas membrane-embedded free unsaturated fatty acid moieties were not a suitable substrate for either isoenzyme. The oxygenation products derived from the biomembranes were the 9- and 13-hydroperoxides of linoleic acid residues, in a molar ratio of 1.0 to 1.7, and the 9- and 13-hydroperoxides of α-linolenic acid residues, in a molar ratio of 1.0 to 0.1. The R S ratios of 13-hydroperoxy-9Z,11E-octadecadienoic acid and 9-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid were found to be 0.5 and 25.0, respectively. These stereospecificity values were much higher than those of hydroperoxides isolated after incubation of lipoxygenase-2 with non-membraneous fatty acids or their methyl esters. The hydroperoxy fatty acids produced were distributed in neutral lipids and phospholipids isolated from soybean membranes, the former being oxidized to a larger extent. Furthermore, both intracellular and plasma membranes were substrates for the enzymic oxygenation, with a preference for those of chloroplasts followed by those of Golgi apparatus, endoplasmic reticulum, plasma membrane and mitochondria. These data point towards a different action of the two lipoxygenases in soybean cells. We suggest that the type-2 enzyme plays a role in the in vivo remodelling of biomembranes. The physiological relevance of these findings is discussed.
AB - The ability of soybean lipoxygenases-1 and -2 to oxygenate biomembranes isolated from soybean seedlings has been investigated. Constituents of the lipid bilayer were analyzed by means of reversed phase and chiral phase high performance liquid chromatography, gas chromatography/mass spectrometry, high performance thin layer chromatography and uv spectroscopy. Evidence is presented that soybean lipoxygenase-2, at variance with the type-1 enzyme, oxygenates the esterified unsaturated fatty acid moieties in biomembranes, whereas membrane-embedded free unsaturated fatty acid moieties were not a suitable substrate for either isoenzyme. The oxygenation products derived from the biomembranes were the 9- and 13-hydroperoxides of linoleic acid residues, in a molar ratio of 1.0 to 1.7, and the 9- and 13-hydroperoxides of α-linolenic acid residues, in a molar ratio of 1.0 to 0.1. The R S ratios of 13-hydroperoxy-9Z,11E-octadecadienoic acid and 9-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid were found to be 0.5 and 25.0, respectively. These stereospecificity values were much higher than those of hydroperoxides isolated after incubation of lipoxygenase-2 with non-membraneous fatty acids or their methyl esters. The hydroperoxy fatty acids produced were distributed in neutral lipids and phospholipids isolated from soybean membranes, the former being oxidized to a larger extent. Furthermore, both intracellular and plasma membranes were substrates for the enzymic oxygenation, with a preference for those of chloroplasts followed by those of Golgi apparatus, endoplasmic reticulum, plasma membrane and mitochondria. These data point towards a different action of the two lipoxygenases in soybean cells. We suggest that the type-2 enzyme plays a role in the in vivo remodelling of biomembranes. The physiological relevance of these findings is discussed.
KW - (G. max)
KW - Biomembrane
KW - Lipoxygenase-1
KW - Lipoxygenase-2
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U2 - 10.1016/0005-2736(94)90046-9
DO - 10.1016/0005-2736(94)90046-9
M3 - Article
C2 - 8110809
AN - SCOPUS:0028125719
VL - 1190
SP - 164
EP - 169
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
SN - 0005-2736
IS - 1
ER -