Inhibitory effect of arachidonic acid on venom acetylcholinesterase

The venom of krait (Bungarus sindanus), an Elapidae snake, contains high level of acetylcholinesterase (AChE) activity. The effect of arachidonic acid on krait (Bungarus sindanus) venom AChE (acetylcholine hydrolase, EC 3.1.1.7) was studied using kinetic methods. This study evaluated for the first time whether arachidonic acid acts as potential AChE inhibitor of krait venom. Kinetic studies, using Line-Weaver Burk and Dixon plots, indicated that the inhibition produced by arachidonic acid was non-competitive, i.e., both k(m) and V-max fell with increase in the concentration of arachidonic acid. The concentration of arachidonic acid required to inhibit 50% of enzymatic activity was found to be 1.9 mu M while the inhibitory constant (K-i) was 1.4 mu M. The present results suggest that essential fatty acid (arachidonic acid) may also be used as an inhibitor of snake venom AChE.