Proteinase K (from Tritirachium album ) is a non-specific protease of the serine protease family. Proteinase K is used for the cleavage of proteins in nucleic acid preparations. It is mainly used in nucleic acid purification or for the removal of nucleases. Proteinase K is active under a wide range of reaction conditions, including elevated temperatures and presence of SDS. Directions for use Foreign activity: RNAse and DNAse not detectable Optimum temperature: +65 °C. Activity at +65 °C is ca. 12 x higher than at +25 °C. Over +65 °C, inactivation due to denaturation. Activators: Denaturating agents like SDS (0,5-1 %), urea. Inhibitors: Inhibition with Hg 2+ -ions, DFP, PMSF and phenol. Not inhibited by EDTA, sulfhydryl reagents and trypsin or chymotryps ininhibitors. Stability: pH 4.0-12.5. pH optimum: 8,0. Also stable even when denaturing agents, e.g. SDS and urea are present. Stabilisers: Ca 2+ -ions (1-5 mM) prevent autolysis. Proteinase K ≥30 U/mg, lyophilized Proteinase K is often used for cell and tissue disruption and for isolation and purification of nucleic acids. Directions for use The recommended working concentration: 50-100 µg/ml for protein and up to 2 mg/ml for tissue treatment. Unit definition One unit is defined as the amount of enzyme that hydrolyzes a defined casein substrate to 1 μM L-tyrosine per minute at 55 °C and pH 8.0. Not a medical device / Not an IVD product