Laboratoire de Physiologie des Organes Végétaux, Centre National de la Recherche Scientifique, 4ter route des Gardes, 92190 Meudon, France.
Plant Physiol. 1992 Mar;98(3):971-8. doi: 10.1104/pp.98.3.971.
A membrane-associated lipoxygenase and a soluble lipoxygenase have been identified in carnation (Dianthus caryophyllus L. cv Rêve) petals. Treatments of microsomal membranes by nonionic or zwitterionic detergents indicated that lipoxygenase is tightly bound to the membranes. By phase separation in Triton X-114, microsomal lipoxygenase can be identified in part as an integral membrane protein. Soluble lipoxygenase had an optimum pH range of 4.9 to 5.8, whereas microsomal lipoxygenase exhibited maximum activity at pH 6.1. Both soluble and membrane-associated lipoxygenases produced carbonyl compounds and hydroperoxides simultaneously, in the presence of oxygen. The membranous enzyme was fully inhibited by 0.1 millimolar n-propyl gallate, nordihydroguaiaretic acid, or salicylhydroxamic acid, but the effect of the three inhibitors on the soluble enzyme was much lower. The soluble lipoxygenase is polymorphic and three isoforms greatly differing by their isoelectric points were identified. Lipoxygenase activity in flowers was maximal at the beginning of withering, both in the microsomal and the soluble fractions. Substantial variations in the ratio of the two forms of lipoxygenase were noted at different sampling dates. Our results allowed us to formulate the hypothesis of a strong association of one soluble form with defined membrane constituents.
在康乃馨（Dianthus caryophyllus L. cv Rêve）花瓣中鉴定出一种膜相关的脂氧合酶和一种可溶性脂氧合酶。用非离子型或两性离子型去污剂处理微粒体膜表明，脂氧合酶与膜紧密结合。通过 Triton X-114 的相分离，可以将微粒体脂氧合酶部分鉴定为一种完整的膜蛋白。可溶性脂氧合酶的最适 pH 范围为 4.9 至 5.8，而微粒体脂氧合酶在 pH 6.1 时表现出最大活性。可溶性和膜结合的脂氧合酶都能同时在氧存在下产生羰基化合物和氢过氧化物。膜酶被 0.1 毫摩尔丙基没食子酸、去甲二氢愈创木酸或水杨羟肟酸完全抑制，但这三种抑制剂对可溶性酶的作用要低得多。可溶性脂氧合酶是多态的，鉴定出三种等电点差异很大的同工酶。在衰老开始时，花朵中的脂氧合酶活性在微粒体和可溶性部分均达到最大值。在不同的采样日期，两种形式的脂氧合酶的比例有很大变化。我们的结果使我们能够提出一种假设，即一种可溶性形式与特定的膜成分强烈相关。
