Change properties of article, clamping set of teeth round (8)
I believe the answer is:
'change' is the definition.
(denaturing is a kind of changing)
'properties of article clamping set of teeth round' is the wordplay.
I cannot really see how this works, but
'article' could be 'a' (the indefinite article in English) and 'a' is present in the answer.
'teeth' could be 'denture' (I have seen 'False teeth ' mean 'denture' so perhaps 'teeth' could also mean 'denture') and 'denture' is present in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for denature that I've seen before include "Spoil" , "Change" , "Contaminate" , "Take away the inherent properties of" .)