The function of MOCOS (molybdenum cofactor sulfurase, ENSG00000075643) is as follows. Sulfurates the molybdenum cofactor (PubMed:34356852). Sulfation of molybdenum is essential for xanthine dehydrogenase (XDH) and aldehyde oxidase (ADO) enzymes in which molybdenum cofactor is liganded by 1 oxygen and 1 sulfur atom in active form (PubMed:34356852). In vitro, the C-terminal domain is able to reduce N- hydroxylated prodrugs, such as benzamidoxime (PubMed:16973608). {ECO:0000255|HAMAP-Rule:MF_03050, ECO:0000269|PubMed:16973608, ECO:0000269|PubMed:34356852}.