denature de·na·ture (dē-nā'chər)
v. de·na·tured, de·na·tur·ing, de·na·tures
To change the nature or natural qualities of.
To render unfit to eat or drink without destroying usefulness in other applications, especially adding methyl alcohol to ethyl alcohol.
To alter the chemical structure of a protein, as with heat, alkali, or acid, so that some of its original properties, especially its biological activity, are diminished or eliminated.