Gupta S, Sanyal S N, Duggal C L
Department of Zoology, Panjab University, Chandigarh, India.
Acta Vet Hung. 1991;39(3-4):165-74.
Acetylcholinesterase (EC 3.1.1.7) activity was demonstrated in whole worm homogenates of adult Ascaridia galli with acetylthiocholine as substrate. The pH optimum was not measurable because of an autohydrolysis of the substrate. The Michaelis constant (Km) was 4 mM with saturation by excess substrate. Optimum enzyme activity was noted at a protein concentration of 200 mg/ml assay medium and at a temperature of 37 degrees C. Arrhenius plot of temperature dependence of the enzyme activity showed an energy of activation (delta Ea) of 28.962 K joule/mole above, and 25.448 K joule/mole below, the transition temperature (37 degrees C). Complete inhibition by eserine (physostigmine), a specific and classical acetylcholinesterase inhibitor, established the identity of the enzyme. A marginally higher enzyme activity was observed in females than in males as well as in homogenates from worms of mixed sexes. The enzyme was markedly activated by divalent metal cations such as Fe2+, Mg2+, Cd2+, Cu2+, Zn2+ and Ca2+, while Co2+ and Mn2+ inhibited the activity. Piperazine adipate at a concentration of 10(-3) M caused 45.5% and albendazole, a benzimidazole anthelmintic, 37.5% inhibition in the enzyme activity, while levamisole and mebendazole proved to be practically ineffective, causing an inhibition of 12 and 9%, respectively.
以乙酰硫代胆碱为底物，在成年鸡蛔虫的全虫匀浆中检测到了乙酰胆碱酯酶（EC 3.1.1.7）活性。由于底物的自动水解，无法测定最适pH值。在底物过量饱和的情况下，米氏常数（Km）为4 mM。在测定培养基中蛋白质浓度为200 mg/ml且温度为37℃时，观察到最佳酶活性。酶活性对温度依赖性的阿伦尼乌斯曲线显示，在转变温度（37℃）以上，活化能（ΔEa）为28.962千焦/摩尔，在转变温度以下为25.448千焦/摩尔。特异性经典乙酰胆碱酯酶抑制剂毒扁豆碱（依色林）可完全抑制该酶，从而确定了该酶的性质。观察到雌性蛔虫以及混合性别的蛔虫匀浆中的酶活性略高于雄性。该酶被二价金属阳离子如Fe2+、Mg2+、Cd2+、Cu2+、Zn2+和Ca2+显著激活，而Co2+和Mn2+则抑制其活性。浓度为10(-3) M的己二酸哌嗪对酶活性的抑制率为45.5%，苯并咪唑驱虫药阿苯达唑的抑制率为37.5%，而左旋咪唑和甲苯达唑实际上无效，抑制率分别为12%和9%。
