Grechkin A N, Kuramshin R A, Latypov S K, Gafarova T E, Ilyasov A V
Institute of Biology, USSR Academy of Sciences, Kazan.
Eur J Biochem. 1991 Jul 15;199(2):451-7. doi: 10.1111/j.1432-1033.1991.tb16143.x.
Metabolism of [1-14C]linolenic acid, 13-hydroperoxy-8(Z),11(E),15(Z)-[1-14C]octadecatrienoic acid (13-HPOT) and 9-hydroperoxy-10(E),12(Z),15(Z)-[1-14C]octadecatrienoic acid (9-HPOT) was studied by enzyme preparations from flax, wheat and corn seeds, containing two enzymes of fatty acid metabolism, namely, lipoxygenase and hydroperoxide dehydrase. Along with the previously known products of the hydroperoxide dehydrase pathway, the radiolabel was incorporated into some more polar metabolites. These polar products 1 and 4, formed from 13-HPOT and 9-HPOT, respectively, were purified by reversed-phase and normal-phase HPLC, and investigated by ultraviolet spectroscopy, chemical-ionization and electron-impact mass spectrometry, and 1H-NMR. The data obtained suggest that metabolites 1 and 4 are 9-hydroperoxy-12-oxo-13-hydroxy-10(E),15(Z)-octadecadienoic acid and 9-hydroxy-10-oxo-13-hydroperoxy-11(E),15(Z)-octadecadienoic acid, respectively. 12-oxo-13-hydroxy-9(Z),15(Z)-[1-14C]octadecadienoic acid (12,13-alpha-ketol) and 9-hydroxy-10-oxo-12(Z),15(Z)-[1-14C]octadecadienoic acid (9,10-alpha-keto) are the direct precursors of metabolites 1 and 4, respectively. Metabolites 1 and 4 are formed from the corresponding HPOT precursors in two stages; (a) conversion of hydroperoxide into the alpha-ketol by hydroperoxide dehydrase and (b) the lipoxygenase oxidation of the alpha-ketol. Different lipoxygenases were found to oxidize alpha-ketols. Oxidation of the 3(Z)-buten-1-onyl moiety of alpha-ketols presents an unusual and previously unknown type of lipoxygenase reaction.
利用亚麻、小麦和玉米种子中的酶制剂研究了[1-¹⁴C]亚麻酸、13-氢过氧-8(Z),11(E),15(Z)-[1-¹⁴C]十八碳三烯酸（13-HPOT）和9-氢过氧-10(E),12(Z),15(Z)-[1-¹⁴C]十八碳三烯酸（9-HPOT）的代谢情况，这些种子含有脂肪酸代谢的两种酶，即脂氧合酶和氢过氧化物脱水酶。除了氢过氧化物脱水酶途径中先前已知的产物外，放射性标记还掺入了一些极性更强的代谢产物中。分别由13-HPOT和9-HPOT形成的这些极性产物1和4，通过反相和正相高效液相色谱法进行纯化，并通过紫外光谱、化学电离和电子轰击质谱以及¹H-NMR进行研究。所得数据表明，代谢产物1和4分别是9-氢过氧-12-氧代-13-羟基-10(E),15(Z)-十八碳二烯酸和9-羟基-10-氧代-13-氢过氧-11(E),15(Z)-十八碳二烯酸。12-氧代-13-羟基-9(Z),15(Z)-[1-¹⁴C]十八碳二烯酸（12,13-α-酮醇）和9-羟基-10-氧代-12(Z),15(Z)-[1-¹⁴C]十八碳二烯酸（9,10-α-酮醇）分别是代谢产物1和4的直接前体。代谢产物1和4由相应的HPOT前体分两个阶段形成；(a) 氢过氧化物脱水酶将氢过氧化物转化为α-酮醇，以及(b) α-酮醇的脂氧合酶氧化。发现不同的脂氧合酶会氧化α-酮醇。α-酮醇的3(Z)-丁烯-1-烯基部分的氧化呈现出一种不同寻常且先前未知的脂氧合酶反应类型。
