Native Proteinase K, product codes PROK and PROKS have been discontinued and superseded with Recombinant Proteinase K, product codes PROKR and PROKRS. The recombinant products meet the same specifications as the native products.
Proteinase K is a serine protease with broad specificity towards aliphatic, aromatic and other hydrophobic amino acids. PROK has a molecular weight of 27,000 daltons and is Ca2+ dependent. It is not inactivated by metal ion chelating agents such as EDTA, sulfhydryl reagents, PCMB, TLCK, or TPCK. It also retains activity in 0.5% SDS. It can be inhibited by PMSF or DFP.
Stability/Storage: The lyophilized powder is stable for one year at 2-8°C. Solutions in 50mM Tris-HCl, pH 8.0 with 1mM CaCl2 are stable for months at 2-8°C. Store at 2-8°C.
Unit Definition: One Unit releases one micromole of Folin positive amino acids, measured as tyrosine, at 37°C, pH 7.5, using urea denatured hemoglobin as the substrate.