Dose-response curves (A, B) and kinetic analyses (C, D) conducted in the absence or presence of two well-characterized IDE inhibitors: P12–3A (A, C) and ML345 (B, D). For dose-response curves, data are mean ± SEM for each of 3 independent experiments conducted on separate days. For kinetic experiments, data are expressed as double-reciprocal plots; for clarity, we show a single linear regression curve is drawn from the mean ± SEM of 3 independent experiments. Kinetic parameters derived from these results are provided in Table 3.