RESUMEN
Selenium-binding protein 1 (SELENBP1) has been associated with several cancers, although its exact role is unknown. We show that SELENBP1 is a methanethiol oxidase (MTO), related to the MTO in methylotrophic bacteria, that converts methanethiol to H2O2, formaldehyde, and H2S, an activity not previously known to exist in humans. We identified mutations in SELENBP1 in five patients with cabbage-like breath odor. The malodor was attributable to high levels of methanethiol and dimethylsulfide, the main odorous compounds in their breath. Elevated urinary excretion of dimethylsulfoxide was associated with MTO deficiency. Patient fibroblasts had low SELENBP1 protein levels and were deficient in MTO enzymatic activity; these effects were reversed by lentivirus-mediated expression of wild-type SELENBP1. Selenbp1-knockout mice showed biochemical characteristics similar to those in humans. Our data reveal a potentially frequent inborn error of metabolism that results from MTO deficiency and leads to a malodor syndrome.
Asunto(s)
Halitosis/genética , Oxidorreductasas/genética , Proteínas de Unión al Selenio/genética , Animales , Pruebas Respiratorias , Línea Celular , Células Cultivadas , Dimetilsulfóxido/sangre , Dimetilsulfóxido/líquido cefalorraquídeo , Dimetilsulfóxido/orina , Halitosis/enzimología , Humanos , Ratones Endogámicos C57BL , Ratones Noqueados , Mutación , Proteínas de Unión al Selenio/deficiencia , Proteínas de Unión al Selenio/metabolismoRESUMEN
A gas chromatographic procedure for the determination of dimethyl sulfoxide in serum, plasma, urine, and CSF is described. Features of the method include simple sample preparation, excellent accuracy, linearity, and precision. Results obtained on patient samples following intravenous administration are presented.