obsolete uracil/thymine dehydrogenase activity true uracil/thymine dehydrogenase activity OBSOLETE. Catalysis of the reactions: uracil + H2O + acceptor = barbiturate + reduced acceptor; and thymine + H2O + acceptor = 5-methylbarbiturate + reduced acceptor. uracil:acceptor oxidoreductase activity GO:0043835 This term was made obsolete because it represents two separate molecular functions. molecular_function uracil dehydrogenase activity thymine dehydrogenase activity