Proteinase K

Proteinase K is a broad-spectrum serine protease. Our product is derived from recombinant Pichia pastoris strains expressing the endoproteinase gene originally sourced from the fungus Tritirachium album limber. It is a highly active enzyme widely used in the hydrolysis of a variety of proteins and enzymatic contaminants (including endonucleases, exonucleases, DNases, and RNases). Proteinase K is therefore commonly used for DNA preparations as it does not impair DNA integrity. Proteinase K preferentially cleaves peptide bonds adjacent to the carboxyl end of hydrophobic amino acids (aliphatic, aromatic, etc.) and exhibits excellent performance under various conditions such as different pH values, buffer types, detergents (e.g. SDS), chelating agents (e.g. EDTA), and temperatures. Proteinase K is also used for enzyme mapping and the removal of unwanted enzymes from DNA preparations to enhance cloning efficiency. Except the isolation of genome, it can also take a job in detection of enzyme localization or removal of enzymes from DNA to improve cloning efficiency.

Appropriate working concentration of proteinase K is always among the range of 0.05 to 1 mg/mL. The activity of the enzyme can be stimulated by 0.2 to 1% SDS or by 1 to 4 M urea. It is activated by calcium (1-5 mM). Calcium ions do not affect the enzyme activity, but it contributes to the thermal stability and protects the proteinase from autolysis. Calcium ion has a regulatory function for the substrate binding site of proteinase K. The enzyme is inactivated by DIFP or PMSF. However, it is not inhibited by EDTA, iodoacetic acid, trypsin-specific inhibitor TLCK, chymotrypsin-specific inhibitor TPCK, and p-chloromercuribenzoate.

We recommend an optimum pH of 7.5 to 8.0 and optimum temperature at 50 to 55°C. Rapid denaturation will occur above 65°C. It is inactivated under 95°C for 10 min.

References:

[1] Kraus, E., et al. Proteinase K from the Mold Tritirachium album limber, Specificity and Mode of Action. Z. Physiol. Chem., 357:939; 1976.

[2] Jany, K.D., et al. Amino Acid Sequence of Proteinase K from the Mold, Tritirachium albumlimber. Proteinase K; a Subtilisin-related Enzyme with Disulfide Bonds. FEBS Letter, 199,139.1986.