Abstract
The present investigation addresses the mode of inhibition of the camel retinal acetylcholinesterase (AChE) activity by gallamine triethiodide, which is known to be a specific non-depolarizing neuromuscular blocking agent and polar cholinergic antagonist. This study gave the following results: it was found that gallamine (GA) reversibly inhibited the AChE activity in a concentration dependent manner, the IC
5o being about 0.633 mM. The
K
m for the hydrolysis of acetylthiocholine iodide by AChE was found to be 0.0803 mM in the control system, and the value increased by 19–463% in the GA (0.125–1.0 mM) treated systems. The
V
max was 0.649 μmol/min per mg protein for the control as well as GA treated systems. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition is of the reversible competitive type. The
K
i, value was estimated as 0.160 mM. The
K
i, value increased with an increase in substrate concentration. The turnover number (
cat) and specificity constant (
K
sp) were 62.1 min
-1 and 7.73 x 10
5 (M-min)
-1 in the control system while the value for one parameter (Agp) was decreased by 25–83% in the GA (0.125–1.0 mM) treated systems