Ahmed Mushtaq, Khan Shahan Zeb, Sher Naila, Rehman Zia Ur, Mushtaq Nadia, Khan Rahmat Ali
Department of Biotechnology, University of Science and Technology Bannu-KPK, Pakistan.
Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
J Venom Anim Toxins Incl Trop Dis. 2021 Apr 9;27:e20200047. doi: 10.1590/1678-9199-JVATITD-2020-0047. eCollection 2021.
The venom of the krait (), an Elapidae snake, is highly toxic to humans and contains a great amount of acetylcholinesterase (AChE). The enzyme AChE provokes the hydrolysis of substrate acetylcholine (ACh) in the nervous system and terminates nerve impulse. Different inhibitors inactivate AChE and lead to ACh accumulation and disrupted neurotransmission.
The present study was designed to evaluate the effect of palladium(II) complex as antivenom against krait venom AChE using kinetics methods.
Statistical analysis showed that krait venom AChE inhibition decreases with the increase of Pd(II) complex (0.025-0.05 µM) and exerted 61% inhibition against the AChE at a fixed concentration (0.5 mM) of ACh. Kinetic analysis using the Lineweaver Burk plot showed that Pd(II) caused a competitive inhibition. The compound Pd(II) complex binds at the active site of the enzyme. It was observed that (Michaelis-Menten constant of AChE-ACh into AChE and product) increased from 0.108 to 0.310 mM (45.74 to 318.35%) and remained constant with an increase of Pd(II) complex concentrations. In AChE was found to increase from 0.0912 to 0.025 µM (29.82-72.58%) and did not affect the with an increase of ACh from (0.05-1 mM). (inhibitory constant) was estimated to be 0.029µM for snake venom; while the was estimated to be 0.4 mM. The calculated IC for Pd(II) complex was found to be 0.043 µM at constant ACh concentration (0.5 mM).
The results show that the Pd(II) complex can be deliberated as an inhibitor of AChE.
眼镜蛇科蛇类金环蛇的毒液对人类毒性极强，且含有大量乙酰胆碱酯酶（AChE）。该酶可促使神经系统中的底物乙酰胆碱（ACh）水解，从而终止神经冲动。不同的抑制剂可使AChE失活，导致ACh积累并扰乱神经传递。
本研究旨在采用动力学方法评估钯（II）配合物作为抗金环蛇毒AChE的效果。
统计分析表明，随着钯（II）配合物（0.025 - 0.05 μM）浓度的增加，金环蛇毒AChE的抑制作用减弱，在ACh固定浓度（0.5 mM）下对AChE的抑制率为61%。使用Lineweaver Burk图进行动力学分析表明，钯（II）产生竞争性抑制作用。化合物钯（II）配合物与酶的活性位点结合。观察到Km（AChE - ACh转化为AChE和产物的米氏常数）从0.108增加到0.310 mM（45.74%至318.35%），且随着钯（II）配合物浓度的增加，Vmax保持不变。在AChE中，Ki被发现从0.0912增加到0.025 μM（29.82% - 72.58%），并且随着ACh从（0.05 - 1 mM）增加，不影响Vmax。蛇毒的Ki（抑制常数）估计为0.029 μM；而Km估计为0.4 mM。在ACh恒定浓度（0.5 mM）下，钯（II）配合物的计算IC50为0.043 μM。
结果表明，钯（II）配合物可被视为AChE的抑制剂。
