WordNet records no synonym and no antonym for denature. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
add nonfissionable material to (fissionable material) so as to make unsuitable for use in an atomic bomb
modify (as a native protein) especially by heat, acid, alkali, or ultraviolet radiation so that all of the original properties are removed or diminished
make (alcohol) unfit for drinking without impairing usefulness for other purposes
Synonyms, antonyms and the broader and narrower relations for denature come from Princeton University’s WordNet. Full sources and licences.