S-Methylisothiourea sulfate is a competitive inhibitor of iNOS activity at the L-arginine site.
S-Methylisothiourea sulfate prevents the NO-mediated cytotoxic effect of LPS in cultured macrophages.
S-Methylisothiourea sulfate (100 nM-100 μM) exhibits inhibitory effects on LPS (ug/mL)-induced nitrite production in J774.2 macrophages and rat aortic vascular smooth muscle cells.
S-Methylisothiourea sulfate (up to 1 mM) does not inhibit the activity of xanthine oxidase, diaphorase, lactate dehydrogenase, monoamine oxidase, catalase, cytochrome P450, or superoxide dismutase.