Proteinase K

Proteinase K (Protease K) is a nonspecific serine protease that is useful for general digestion of proteins. Proteinase K is active in the presence of SDS or urea and over a wide range of pH (4-12), salt concentrations, and temperatures. Proteinase K can be use for promoting methods of viral nucleic acid extraction, and detection^[1][2][3][4]. In Vitro:Proteinase K enzyme can be used to break amid bond between MTX and BSA and also amidic bonds in BSA structure^[2].

Guidelines (Following is our recommended protocol. This protocol only provides a guideline, and should be modified according to your specific needs).
Proteinase K with superior protein-degrading property, can be used to detect the SARS-COV2 viral component directly from inoculated viral transport medium (VTM) without RNA extraction^[3].
Protocol of rRTPCR detection of SARS-CoV2^[3]:
1.Separate VTM of each SARS-COV2 samples into three EP tubes (45 μL per tube);
2.Add 2.5 μL (20 mg/mL concentrated) proteinase K (PK), making a final concentration of PK ~1 mg/ml VTM;
3.Incubate at 25°C for 5 min;
4.Incubate at 60°C for 15 min;
5.Incubate at 98°C for 10 min, and store samples at 4°C;
6.Use 5 μL of extracted RNA as template to execute rRTPCR assay;
7.Exert rRTPCR detection by BIORAD CFX96 Real-Time Thermocycler, with a positive standard of threshold cycle (Ct) values less than 40.
Proteinase K improves the homogenization effects and positive rates of sputum samples, and increases nucleic acid concentration extracted from it^[4].
Protocol of nucleic acid extraction of influenza A virus (IAV)^[4]:
1.Separate specimen into three EP tubes (500 μL per tube);
2.Add 500 μL 0.4 mg/mL Proteinase K buffer, vortex for 20 seconds;
3.Incubate at 55°C for 25 min, vortex 5 seconds every 5 min;
4.Extract RNA by using the Automated Nucleic Acid Extraction System through a paramagnetic beads method (Zhijiang Biotechnology Co., Ltd., Shanghai, China) with 200 μL samples;
5.Evaluate A260/A280 ratio of pure RNA products, with a standard ranged from 1.8 to 2.0.