denature

To denature something is to alter its natural properties or character.

In chemistry, denaturing a protein means disrupting its molecular structure, usually through heat or chemicals—this is what happens when you cook an egg.

Alcohol is denatured by adding substances that make it undrinkable, allowing it to be sold without liquor taxes: denatured alcohol.

More broadly, to denature is to strip something of its essential qualities: The compromise denatured the original proposal.