How to inactivate proteins in organ extracts?

[WS]

Dear Experts!

How to inactivate proteins in an aqueous organ extract? An attempt to
digest them with trypsin failed, probably due to trypsin inhibitor from
blood / serum present in the samples. Heating / boiling comes into my
mind, but this might kill other unknown substances in the extract.

I would like to tell if a certain effect of this extract is due to a
protein or something else.

Any ideas?

Thanks for your input!

Wolfgang