Fig. 3.

Restoration of rTgAPN2 activity by divalent metal ions. rTgAPN2 was pre-incubated at 37°C for 30 min in 50 mM Tris-HCl supplemented with the specified metal chloride, and then the substrate (H-Ala-MCA, 0.1 mM final concentration) was added. (A) Enzyme activity in the presence of 1 µM metal ions. (B) Enzyme activity in the presence of 0.1 µM metal ions. (C) Different concentration of Zn²⁺ ions. (D) Enzyme activity in the presence of EDTA. The differences between samples were evaluated by Student’s t-test (n=3). *P<0.05, **P<0.01.