Voisine R., Vezina L. P., Willemot C.
Department of Food Science and Technology, Universite Laval, Quebec, Canada, G1K 7P4 (R.V., C.W.).
Plant Physiol. 1993 May;102(1):213-218. doi: 10.1104/pp.102.1.213.
Acceleration of membrane deterioration has been observed recently during storage of [gamma]-irradiated cauliflower (Brassica oleracea L., Botrytis group). In the present study, the activity of microsome-associated lipolytic enzymes was investigated in cauliflower florets exposed to 0 or 4 kilograys of [gamma] radiation and stored for 8 d at 13[deg]C. Radiolabeled breakdown products obtained from the metabolism of (16:0/18:2*)-phosphatidylcholine and (16:0/16:0)-phosphatidyl-[N-methyl-3H]choline by microsomal membranes indicated that phospholipase D (EC 3.1.4.4), phosphatidic acid phosphatase (EC 3.1.3.4), and lipolytic acyl hydrolase were associated with the membranes. The rate of phosphatidylcholine catabolism by the membranes increased slowly in control cauliflower during storage. [gamma] irradiation caused an immediate rise in phosphatidylcholine catabolism that remained higher than that of the controls during subsequent storage. Collectively, the data suggest that enhancement of membrane lipolytic activity results from free-radical-induced stress. Rapid increase of the membrane-associated phospholipase D activity may be a key event leading to accelerated membrane deterioration following [gamma] irradiation.
最近在γ辐照花椰菜(甘蓝属,花椰菜组)储存期间观察到膜劣化加速。在本研究中,对暴露于0或4千戈瑞γ辐射并在13℃下储存8天的花椰菜小花中与微粒体相关的脂解酶活性进行了研究。微粒体膜对(16:0/18:2*)-磷脂酰胆碱和(16:0/16:0)-磷脂酰-[N-甲基-3H]胆碱代谢产生的放射性标记分解产物表明,磷脂酶D(EC 3.1.4.4)、磷脂酸磷酸酶(EC 3.1.3.4)和脂解酰基水解酶与膜相关。在储存期间,对照花椰菜中膜对磷脂酰胆碱的分解代谢速率缓慢增加。γ辐照导致磷脂酰胆碱分解代谢立即增加,在随后的储存过程中一直高于对照。总体而言,数据表明膜脂解活性的增强是由自由基诱导的应激引起的。膜相关磷脂酶D活性的快速增加可能是导致γ辐照后膜劣化加速的关键事件。