Fig 7. (a) Michaelis-Menten, (b) Lineweaver-Burk and (c) reversibility assay plots compound 5.

The effect of increasing concentrations of compound 5 over the rate of reaction shown in (a) and the convergence of double-reciprocal plots over the y-axis characterizes compound 5 as a competitive inhibitor relative to the substrate Z-FR-AMC. Additionally, the recovery of enzyme activity after abrupt dilution of a solution containing cruzain and compound 5 after incubation reveals that this compound is acting by a reversible type of inhibition.