*2.1. Materials*

Human pro-MMP-8 was purchased from R&D Systems (Minneapolis, MN, USA). p-aminomercuric acetate and MMP-8 fluorogenic substrate (DNP-Pro-Leu-Ala-Tyr-Trp-Ala-Arg) were obtained from Sigma-Aldrich (St. Louis, MO). MMP-9 inhibitor screening assay kit was obtained from Abcam (Cambridge, UK). All other reagents were purchased from Fisher Scientific (Waltham, MA, USA).
