Clapp C H, Banerjee A, Rotenberg S A
Biochemistry. 1985 Apr 9;24(8):1826-30. doi: 10.1021/bi00329a004.
Micromolar concentrations of N-octylhydroxylamine dramatically increase the induction period in the conversion of linoleic acid to 13(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid (13-HPOD) catalyzed by soybean lipoxygenase 1. The induction period produced by N-octylhydroxylamine is abolished by 13-HPOD but not by the corresponding hydroxy acid. Addition of a catalytic amount of lipoxygenase to a mixture of 13-HPOD and N-octylhydroxylamine results in consumption of approximately 1 mumol of 13-HPOD/mumol of N-octylhydroxylamine present. These results can be explained by a model in which 13-HPOD oxidizes the enzyme from an inactive ferrous form to an active ferric form, as proposed by previous workers, and N-octylhydroxylamine reduces the enzyme back to the ferrous form. Consistent with this model, the ESR signal at g = 6.1 characteristic of ferric lipoxygenase is rapidly abolished by N-octylhydroxylamine and can be regenerated by 13-HPOD. These results provide additional support for earlier proposals that ferric lipoxygenase is the catalytically active form and also establish a novel method of inhibiting enzymes in this class. The octyl group of N-octylhydroxylamine appears to contribute to binding near the iron, since hydroxylamine and N-methylhydroxylamine do not extend the induction period. In the n-RNHOH series, activity passes through an optimum at R = decyl.
微摩尔浓度的N-辛基羟胺能显著延长大豆脂氧合酶1催化亚油酸转化为13(S)-氢过氧-顺-9,反-11-十八碳二烯酸（13-HPOD）的诱导期。N-辛基羟胺产生的诱导期可被13-HPOD消除，但相应的羟基酸则不能。向13-HPOD和N-辛基羟胺的混合物中添加催化量的脂氧合酶，会导致每微摩尔存在的N-辛基羟胺消耗约1微摩尔的13-HPOD。这些结果可以用一个模型来解释，即如先前研究人员所提出的，13-HPOD将酶从无活性的亚铁形式氧化为活性的铁形式，而N-辛基羟胺将酶还原回亚铁形式。与该模型一致，铁脂氧合酶特有的g = 6.1处的电子自旋共振信号会被N-辛基羟胺迅速消除，并可被13-HPOD再生。这些结果为早期关于铁脂氧合酶是催化活性形式的提议提供了额外支持，同时也建立了一种抑制这类酶的新方法。N-辛基羟胺的辛基似乎有助于在铁附近结合，因为羟胺和N-甲基羟胺不会延长诱导期。在n-RNHOH系列中，活性在R = 癸基时达到最佳。
