Abdul Rahim Nor Aliza, Othman Marlini, Sabri Muna, Stanley David W
Department of Paraclinical Sciences, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia.
Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia.
Enzyme Res. 2018 May 15;2018:9703413. doi: 10.1155/2018/9703413. eCollection 2018.
Phospholipase A (PLA) is a secretory digestive enzyme that hydrolyzes ester bond at position of dietary phospholipids, creating free fatty acid and lysophospholipid. The free fatty acids (arachidonic acid) are absorbed into midgut cells. and digestive PLA was characterized using a microplate PLA assay. The enzyme showed substantial activities at 6 and 8 g/l of protein concentration with optimal activity at 20 and 25 g/l of substrate concentration in and , respectively. PLA activity from both mosquitoes increased in a linear function up to 1 hour of the reaction time. Both enzymes were sensitive to pH and temperature. PLA showed higher enzyme activities in pH 8.0 and pH 9.0 from and , respectively, at 40°C of incubation. The PLA activity decreased in the presence of 5 mM and 0.5 mM site specific PLA inhibitor, oleyloxyethylphosphorylcholine. Based on the migration pattern of the partially purified PLA on SDS-PAGE, the protein mass of PLA is approximately 20-25 kDa for both mosquitoes. The information on PLA properties derived from this study may facilitate in devising mosquitoes control strategies especially in the development of inhibitors targeting the enzyme active site.
磷脂酶A（PLA）是一种分泌性消化酶，可水解膳食磷脂特定位置的酯键，生成游离脂肪酸和溶血磷脂。游离脂肪酸（花生四烯酸）被吸收到中肠细胞中。采用微孔板PLA分析法对消化性PLA进行了表征。该酶在蛋白质浓度为6和8 g/l时具有较高活性，在底物浓度分别为20和25 g/l时活性最佳。两种蚊子的PLA活性在反应时间长达1小时内呈线性增加。两种酶对pH和温度均敏感。在40°C孵育时，PLA在pH 8.0和pH 9.0时分别表现出较高的酶活性。在存在5 mM和0.5 mM位点特异性PLA抑制剂油酰氧基乙基磷酰胆碱的情况下，PLA活性降低。根据部分纯化的PLA在SDS-PAGE上的迁移模式，两种蚊子的PLA蛋白质量约为20-25 kDa。本研究得出的PLA特性信息可能有助于制定蚊子控制策略，特别是在开发针对酶活性位点的抑制剂方面。
