Cleavage of type V collagen by MMP-12 CAT domain (top) and trypsin (bottom). Type V collagen (333 nM) was treated with 4–32 nM of MMP-12 or 0.5–4 nM of trypsin in 50 mM Tris•HCl, pH 7.5, 150 mM NaCl, 5 mM CaCl2, 0.05% Brij35, 1 μM ZnCl2 overnight at either room temperature (gels on the left) or 37 °C (gels on the right). MMP12 CAT domain or trypsin catalyzed the hydrolysis of type V collagen at 37 °C, but not at room temperature. “Lad” is the molecular weight ladder, “Col V” is type V collagen alone, and “Enzm” is trypsin alone.