| Summary: | Cyanide can be produced by different endogenous metabolisms; therefore human blood contains it in low concentrations. The major route of cyanide detoxification is by its conversion to non-toxic thiocyanate. Rhodanese is the main enzyme responsible for this detoxification process. While low concentrations of toxic cyanide should not be a burden for human organs, complications may occur when cyanide concentrations are increased, furthermore it may increase to lethal concentrations. As many edible plants, seeds and smoke contain cyanide, poisoning can often occur accidentally. Cyanide can inhibit the activity of many metalloenzymes, including hemoglobin and cytochrome c oxidase (CcO). Inhibition of these proteins can lead to life-threatening conditions. The sulfur donated by oxothiomolybdate, "Mo2O2(μ-S)2(S2)", complexes, reacts with cyanide, forming non-toxic thiocyanate. Complexes 1, 2, 3 and 4 bearing amino acid and a terminal disulfide ligand, model the reactivity of the rhodanese enzyme and can "mimic" the activity of the endogenous cyanide detoxification pathway. Following the isolation of CcO, "in vitro” studies with complexes and cyanide inhibition were performed. Studies using the complexes as a preventive measure for cyanide inhibition, and also as reactivation agents for the inhibited enzyme were performed. Finally, activity of the complexes as catalytic detoxification agents for the reaction of cyanide and thiosulfate in prevention/reactivation reactions were run. - Icelandic Centre for Research (RANNÍS, grant #195726). - University of Iceland Research fund. - Sláturfélag Suðurlands svf. (SS) is thanked for donating the bovine hearts.
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