Fig. 4.

Kinetics of Aβ degradation by plasmin. Plasmin concentration dependence of Aβ cleavage (A). Aβ (40 μm) was incubated with plasmin at the indicated concentrations for 30 min, and the amount of remaining Aβ1–40 was quantified by HPLC. The data represent the mean ± range of two separate experiments. Time dependence of plasmin cleavage of Aβ (B). Aβ1–40 (40 μm) and plasmin (70 nm) were incubated for the indicated times, and the remaining intact Aβ1–40 was quantified. The data represent the mean ± SE, n = 4. Time course of Aβ aggregation (C). Aβ solutions (100 μm) were incubated at 37°C for the indicated times, and changes in aggregation were assessed simultaneously by ThT fluorescence. Time dependence of plasmin degradation of aggregated Aβ (D). After aggregating for 6 hr at 100 μm, Aβ was diluted to 40 μm and incubated in the absence or presence of 70 nm plasmin for up to 6 hr. The quantity of intact Aβ remaining was then quantified by HPLC. These data represent the mean ± SE of three independent experiments.