Cocucci M, Ballarin-Denti A
Centro di Studio del Consiglio Nazionale delle Ricerche per la Biologia Cellulare e Molecolare delle Piante, c/o Istituto di Scienze Botaniche, Università di Milano, 20133 Milano, Italy.
Plant Physiol. 1981 Aug;68(2):377-81. doi: 10.1104/pp.68.2.377.
Membrane preparation (sedimenting between 13,000(g) and 80,000(g)) of germinating radish seeds (Raphanus sativus L.) was active in hydrolyzing ATP and, to a lesser extent, a variety of other phosphorylated compounds. Dicyclohexylcarbodiimide (DCCD) and diethylstilbestrol significantly inhibited the ATPase activity (40%) while their effect on hydrolysis of other phosphorylated compounds was much less.The sucrose density gradient analysis of the membrane preparation showed that the position of the DCCD-sensitive K(+)-dependent ATPase was similar to that found for plasma membrane of other plant material.Cholate treatment of membrane preparation removes almost all phospholipids, and ATPase activity is barely detectable. However, the addition of polar lipids completely restores the ATPase activity but does not restore general phosphatase activity.The ATPase of the polar lipids restored cholate preparation, showed a high sensitivity to DCCD and diethylstilbestrol (up to 90% inhibition), a complete dependence on Mg(2+), and a strong dependence on K(+) at low concentration; the pH optimum of ATPase was close to 6.5, and the K(m) for ATP-Mg was 0.51 millimolar. ATPase activity was much greater when polar lipids from 24-hour-germinated seeds were added.
对发芽萝卜种子（萝卜）进行膜制备（在13,000(g)至80,000(g)之间沉淀），其在水解ATP以及在较小程度上水解多种其他磷酸化化合物方面具有活性。二环己基碳二亚胺（DCCD）和己烯雌酚显著抑制ATP酶活性（40%），而它们对其他磷酸化化合物水解的影响则小得多。对膜制备物进行蔗糖密度梯度分析表明，DCCD敏感的依赖钾离子的ATP酶的位置与在其他植物材料的质膜中发现的位置相似。用胆酸盐处理膜制备物可去除几乎所有磷脂，并且几乎检测不到ATP酶活性。然而，添加极性脂质可完全恢复ATP酶活性，但不能恢复一般磷酸酶活性。极性脂质恢复的胆酸盐制备物中的ATP酶对DCCD和己烯雌酚高度敏感（抑制率高达90%），完全依赖镁离子（Mg(2+)），并且在低浓度下强烈依赖钾离子（K(+)）；ATP酶的最适pH接近6.5，ATP - Mg的米氏常数（K(m)）为0.51毫摩尔。添加来自24小时发芽种子的极性脂质时，ATP酶活性要高得多。
