Figure 6

μPlm-α2-AP complex formation. (a) Human µPlm and α2-AP. M. Molecular weight marker, standard molecular weight is labeled on the left, and molecular weight (KD) of the protein fragments is labeled on the right. 1. Human α2-AP, 50 KD; 2. Human µPlg, 27 KD; 3, Human µPlm; 4, Human µPlg + α2-AP; 5, Human µPlm + α2-AP. (b) Mouse µPlm and α2-AP. Standard molecular weight is labeled on the left, and molecular weight (KD) of the protein fragments is labeled on the right. 1–6, reduced SDS-PAGE; 7–12, non-reduced SDS-PAGE. 1. Mouse µPlm, 28 KD; M, Molecular weight marker, labeled on the left; 2, Mouse α2-AP, 52 KD; 3, Mouse µPlm + Mouse α2-AP; 4. Mouse µPlm; 5, Mouse α2-AP; 6, Mouse µPlm + Mouse α2-AP; 7. Mouse µPlm; 8, Mouse α2-AP; 9, Mouse µPlm + Mouse α2-AP; 10. Mouse µPlm; 11, Mouse α2-AP; 12, Mouse µPlm + Mouse α2-AP. Reaction time, 1–3 and 7–9, 2 min; 4–6 and 10–12, 5 min. Urokinase (1:20) was used to activate µPlg in lanes 3, 4, 6, and 7; while staphylokinase (SAK, 18.5 KD, 1:1) was use to activate µPlg in lanes 9, 10, and 12. Lanes 13–16 were performed in a separate experiment. 13, Mouse µPlg; 14, Mouse µPlm; 15, Mouse µPlm + Mouse α2-AP; 16, Mouse µPlg + Mouse α2-AP. (c) Schematic presentation of the reaction between human α2-AP and µPlm shown in Fig. 4a. The red arrow from µPlm to R364 of human mature α2-AP illustrate the nucleophilic attach of the active site serine of µPlm toward the α2-AP substrate at the R364 (P1) position; (d) schematic presentation of the reaction between mouse α2-AP and µPlm shown in Fig. 4b. The red arrow from µPlm to K148 of α2-AP illustrate the nucleophilic attach of the active site serine of µPlm toward the α2-AP substrate at the K148 (P1) position. Full-length gels are presented in Supplementary Fig. 6.