Proteinase K, originally isolated from the mold Tritirachium album, is a serine protease with broad substrate specificity and relatively high proteolytic activity. It preferentially cleaves ester and peptide bonds adjacent to the C-termini of hydrophobic, aliphatic, or aromatic amino acids. CUSABIO's recombinant proteinase K is highly pure determined by SDS-PAGE and reached up to 95%. It is characterized by high purity, sterility, no bio-burden, and no presence of DNAse, RNAse, DNA, and RNA contaminants. Its enzyme activity was calculated >30U/mg using the absorbance A275 as the vertical axis and different concentrations of a tyrosine as the horizontal axis. The working concentration of proteinase K, usually determined by the temperature, PH, and whether the buffer used contains SDS and urea, is 20mg/mL. This recombinant proteinase K protein is in-stock now.

Proteinase K has a wide range of applications. In nucleic acid extraction and isolation, proteinase K can be used to degrade Dnase/Rnase and DNA-bound histones and lyse cells or tissues. It also digests protein impurities especially endotoxin and separates target nucleic acids from proteins in biological samples, thus improving the purity and safety of nucleic acids and production efficiency. The nucleic acids isolated by proteinase K is often used for the amplification reaction. Denaturing agents such as SDS (1%) can increase the enzymatic activity of proteinase K. In in-situ hybridization, it removes the proteins around the target DNA to facilitate probe infiltration and improves detection sensitivity. Proteinase K is also used to analyze the membrane structure through the modification of proteins on the cell surface. The nucleic acid-based real-time reverse transcriptase-polymerase chain reaction (RT-PCR) test is the primary tool to diagnose the SRAS-CoV-2 infection. Proteinase K is often used to remove unwanted proteins present in the nasal/pharyngeal swab samples and inactivate nucleases that could degrade DNA or RNA during isolation and purification procedures, thus increasing the yield of extracted RNA and improving the detection of viral RNA by RT-PCR.