ON THE INHIBITION OF CAMEL RETINA ACETYLCHOLINESTERASE ACTIVITY BY CYCLOHEXIMIDE IN-VITRO

The kinetic parameters of inhibition of camel retinal acetylcholineste rase (AChE) activity by cycloheximide (CH) were investigated. For the control system, the Michaelis-Menten constant (K-m) for the hydrolysis of acetylthiocholine iodide was found to be 0.076 mmol/L and the V-ma x was 0.547 mu mol/min per mg protein. In contrast, these parameters w ere decreased in the CH-treated systems. Dixon and Lineweaver-Burk plo ts, and their secondary replots, indicated that the inhibition was of the linear mixed type, which seems to be a combination of partial comp etitive and pure noncompetitive inhibition. The values of K'(i(slope)) and K-I(intercept) were estimated to be 3.50 and 5.68 mmol/L, respect ively. K-i was greater than K'(i), indicating that CH has a greater bi nding affinity for the peripheral site than the active site.