Z-FA-FMK can irreversibly inhibit cysteine protease and also inhibit effector caspases.

Z-FA-FMK inhibits the development of Ras-induced carcinogenic tumors and respiratory viral infections in the cardiac tissue of mice with severe combined immunodeficiency (SCID). In a mouse model of intranasal pneumococcal infection, Z-FA-FMK significantly promotes the growth of Streptococcus pneumoniae in both the lungs and the bloodstream.

Z-FA-FMK effectively inhibits T-cell proliferation induced by interleukin-2 (IL-2) and mitogens in vitro. It also prevents the degradation of fibrillar collagen through its actions on fibroblasts and osteoclasts. Furthermore, Z-FA-FMK suppresses the expression of NF-κB-dependent genes in macrophages, thereby inhibiting the production of cytokines induced by lipopolysaccharides.

T cell proliferation following mitogen stimulation is determined using [3H]thymidine incorporation. In brief, PBMCs or purified T cells are seeded in a 96-well plate and stimulated with either PHA (5 μg/ml), costimulated with anti-CD3 mAb (5 μg/ml) and anti-CD28 mAb (2.5 μg/ml) or PMA plus ionomycin in the presence or absence of z-FA-FMK. The cells are cultured for 72 h with the last 16 h pulsed with [methyl-3H]thymidine (0.037 MBq). The cells are harvested onto glass fiber filter mats using a Tomtec automated multiwell harvester. (Only for Reference)