Cleavage of serpins by EspI.

Serpins (5 µg) were incubated (15 h, 37°C) with EspI (1.5 µg). Degradation products were separated via SDS-PAGE using a glycine buffer (a, c, e, g, i) or a tricine buffer (b, d, f, h, j). a, b α1-PI is cleaved into two fragments (∼45 kDa and ∼4 kDa), c, d α1-AC is cleaved into two fragments, e, f AGT is not cleaved by EspI, g, h α2-AP is not cleaved by EspI, i, j ATIII is cleaved only with very low efficiency. Note the formation of inhibitory serpin-enzyme-complexes after incubation with α1-PI and α1-AC. M, molecular weight marker, *, autodegradation product of EspI, **, inhibitory serpin-EspI-complex. Serpin fragments are indicated by an arrow.