Why should I neutralize the proteinase K after incubation?

Proteinase K should be neutralized following incubation to prevent potential digestion of the samples. It also degrades nucleases that may be present in DNA or RNA extraction experiments and protects nucleic acids from nuclease attack. Essentially, proteinase K is removed in order to not over-digest the necessary components of the experiment and maintain the overall sample quality. This step is also important in diagnostic tests because it eliminates false negative results by protecting the RNA or DNA due to the digestion and inactivation of DNases or RNases.