Catalyzes the oxidation of methanethiol, an organosulfur compound known to be produced in substantial amounts by gut bacteria (PubMed:29255262). Selenium-binding protein which may be involved in the sensing of reactive xenobiotics in the cytoplasm. May be involved in intra-Golgi protein transport (By similarity)

NucleusCytoplasm, cytosolMembrane

Extraoral halitosis due to methanethiol oxidase deficiency

An autosomal recessive malodor condition characterized by extraoral blood-borne halitosis resulting from the accumulation of sulfur-containing metabolites. In extraoral blood-borne halitosis, malodorant compounds are carried to the lungs, where they enter the breath. Affected individuals have a cabbage-like breath odor, high levels of methanethiol and dimethylsulfide in oral and nasal breath, and elevated urinary excretion of dimethylsulfoxide in the absence of intake of dimethylsulfide-containing food or use of sulfur-containing medication, lower-gastrointestinal problems, and known metabolic defects, such as methionine adenosyltransferase deficiency and tyrosinemia.