I3MT-3 (1 µM) specifically targets 3MST, exhibiting high inhibitory efficiency (80–90%) at concentrations up to 10 µM in cell lysates from 3MST-overexpressing HEK293 cells. Additionally, it remains virtually inactive against the other two H2S-producing enzymes, even at 100 µM^[1].

I3MT-3 (1 µM) demonstrates high selectivity for 3MST, completely inhibiting 3MST activity in live COS7 cells^[1].

I3MT-3 induces a concentration-dependent decrease in the AzMC (the fluorescent H2S probe) signal when combined with purified human recombinant enzyme, leading to a concentration-dependent reduction in H2S production by inhibiting the catalytic activity of 3-MST, with an IC50 of 13.6 µM^[1].

I3MT-3 exhibits dose-dependent suppression of 3-MST activity in CT26 homogenates, containing the murine variant of the enzyme. The IC50 for murine 3-MST, measured using HMPSNE, is determined to be 2.3 µM, accompanied by a concentration-dependent reduction in AzMC fluorescence^[1].

I3MT-3 (10 µM-100 µM; after 3 h probe AzMC) leads to partial signal inhibition. However, at 100 µM, HMPSNE achieves total suppression of the AzMC-mediated H2S fluorescence. Furthermore, HMPSNE effectively inhibits its target in situ within CT26 cells (with an IC50 of approximately 30 µM)^[2].

I3MT-3 (0-300 μM; 5-50 hours) does not increase MTT conversion at 10 µM. However, at 100 and 300 µM, it triggers an inhibitory response without raising the LDH signal, indicating no observable level of cell necrosis. Additionally, it results in reduced oxygen consumption rate (OCR) profiles in CT26 cells^[2].

I3MT-3 (0-300 μM; 48 hours) progressively inhibits the proliferation of CT26 cells with escalating doses. Cell confluence in samples treated with HMPSNE is monitored hourly for 48 hours using the IncuCyte method^[2].