FIGURE 4.

Egf1.0 and Egf1.0ΔCD inhibit processing of pro-PO, pro-SPH1, and pro-SPH2. A, plasma plus curdlan only served as the positive control (cont). Egf1.0, Egf1.0ΔRD, Egf1.0ΔCD, or Egf0.4 (20 pmol) was added to plasma followed 10 min later by the addition of curdlan. After 10 min reactions were stopped by adding SDS-PAGE sample buffer and boiling for 3 min. The mixtures were then subjected to SDS-PAGE under reducing conditions and immunoblotting using SPH1, SPH2, and PO antibodies. B, inhibition of PO activity generation. Recombinant Egf1.0, Egf1.0ΔRD, Egf1.0ΔCD, or Egf0.4 (0.4 pmol) was combined with purified pro-PO (0.25 pmol) for 10 min followed by the addition of purified PAP1, SPH1, and SPH2. Samples containing pro-PO alone served as the negative control (pro-PO), whereas samples containing pro-PO plus PAP1, SPH1, and SPH2 served as the positive control (Cont). C, immunoblot of the same samples from B using the PO antibody.