Extracellular PEPD activated collagen and total protein biosynthesis in control and “scratched” fibroblast models. Collagen biosynthesis (A,C) and total protein biosynthesis (B,D) in PEPD-treated fibroblasts (1–100 nM) in the presence and absence of EGFR inhibitor (Gefitinib, 0 and 45 µM pretreated cells for 2 h) after 24 and 48 h incubation, respectively. The values were presented as a percent of control cells (0 nM of PEPD). Mean values± SD of three experiments done in replicates is presented. The results are significant at a, b, c < 0.05, and are marked as a vs. control (0 nM of PEPD) of control cells, b vs. control (0 nM of PEPD) of scratched cells, c vs. control (0 nM of PEPD) of scratched cells incubated with gefitinib, respectively. PEPD—prolidase.