Subject: What precisely does an inhibitor do to a protease enzym to denature it?

I am currently conducting my A level biology course work and part of it 
involves investigating the effects of inhibitors on Trypsin and Pepsin. I 
know that heavy metal ions inhibit trypsin but I do not know precisely 
what it is that they do to the enzyme once they have formed a complex with 
it to stop it from acting on the substrate. Although my A level coursework 
needs to be in depth, I am interested in finding out about this as I 
cannot find a detailed explanation of this anywhere. Any information would 
be most helpful, thank you very much for your time.
Kt

Re: What precisely does an inhibitor do to a protease enzym to denature it?