Can I reuse PAA (peracetic acid) once its been in contact with a protein?

Question

Even though the protein is disrupted or washed, can the same PAA left over be used again? Will it have the same reactivity properties or will it be consumed by the protein?

Answer 1

Not sure why you'd want to use the "left over" acid, but there really shouldn't be any reason why not depending on exactly how you used it in the first place.  The peracetic acid is simply acetic acid reacted with peroxide, so it is relatively inexpensive to prepare. Why would you want to re-use it?  From a simply academic point, you should be able to use it again after contact with a protein, and complete separation of the protein from the acid. Since you listed this under Le Chatelier's Principle, it can be assumed you are interested in CH₃COOH + H₂O <==> CH₃COOOH + H₂O and adding a protein to the equation won't shift the equilibrium as long as no reaction takes place.