Figure 4: Determination of mechanism of AChE inhibitory action of lead. The enzyme (50 μg) was assayed at varying concentration ATI at room temperature (26 ± 2°C) in the absence () and presence () of lead (0.5 mM) as described in Materials and Methods. The and values were calculated using the intersections of the straight line at -axis and at the negative abscissa on -axes, respectively.