Fungus-Derived Proteinase K Purified Recombinant is prepared at 20 mg/mL in 10 mM Tris-HCl, 1 mM calcium acetate, pH 7.5 containing 50% glycerol. This Molecular Biology Grade Proteinase K solution is extremely effective on native proteins and can be used to rapidly inactivate endogenous nucleases such as RNases and DNases. The proteinase K solution has been sterile filtered using 0.22 μm filter, which can maintain its activity for a long time at room temperature and low temperature. It is recommended to store at 2-8° for long-term storage.