Merriam-Webster Collegiate Dictionary - denature

 verb  (~d; denaturing)  Date: 1685  transitive verb  1. dehumanize  2. to deprive of natural qualities ; change the nature of: as  a. to make (alcohol) unfit for drinking (as by adding an obnoxious substance) without impairing usefulness for other purposes  b. to modify the molecular structure of (as a protein or DFNA) especially by heat, acid, alkali, or ultraviolet radiation so as to destroy or diminish some of the original properties and especially the specific biological activity  intransitive verb to become ~d  • denaturant noun  • denaturation noun