Effect of peptidase inhibitors on the proteolytic profiles of the four larval instars of Ae. albopictus , and quantitative in-solution assays of the proteolytic activities. A. Samples were pre-incubated for 30 min in the presence of 1 mM PMSF, 100 μM TLCK and 10 μM E-64. The proteolytic activities were detected after incubating the gels for 2 hours at 37°C in Tris–HCl buffer (pH 7.5). The control was processed under the same conditions but in the absence of inhibitors. B. The in-solution assays were performed using the fluorogenic substrate Z-Phe-Arg-AMC in the absence (control) or presence of 100 μM TLCK in 100 mM sodium phosphate (pH 7.5). L1, first larval instar; L2, second larval stage; L3, third larval instar; and L4, fourth larval instar. The numbers on the right indicate the apparent molecular masses of the peptidases (kDa).