Figure 7. SWFPL inhibits the proteolytic activity of intact Karilysin (Kly48) and delays the auto-processing of Kly48 to Kly18.

A) Kly48 was pre-incubated with SWFPL in varying concentrations (2.3 µM to 55.6 µM) followed by addition of the substrate FITC-casein. The SWFPL inhibitory effect was seen as a decrease in Relative Fluorescence Units (RFU) in a dose-response manner. Error bars represent standard deviations between three experiments. B+C) Intact Karilysin (Kly48) at 13 µM was incubated alone (B) or with the peptide inhibitor (C) at 455 µM. At indicated time points samples were withdrawn for SDS-PAGE analysis. It is clear that SWFPL inhibited the time-dependent autoprocessing of Kly48 to Kly38 and Kly18. Even after 48 hours a significant amount of Kly48 was still present.