Proteinase K

• CAT Number: I015394
• CAS Number: 39450-01-6
• Purity: ≥95%

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].
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 ℃ for 5 min;
4.Incubate at 60 ℃ for 15 min;
5.Incubate at 98 ℃ for 10 min, and store samples at 4 ℃;
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 ℃ 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.

Reference

[1]. W Ebeling, et al. Proteinase K From Tritirachium Album Limber. Eur J Biochem . 1974 Aug 15;47(1):91-7.
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[2]. Nosrati H, et al. Multifunctional nanoparticles from albumin for stimuli-responsive efficient dual drug delivery. Bioorg Chem. 2019 Jul;88:102959.
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[3]. Shukla A, et al. Vitality of Proteinase K in rRTPCR Detection of SARS-CoV2 Bypassing RNA Extraction. Front Cell Infect Microbiol. 2021 Nov 3;11:717068. 
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[4]. Yu F, et al. Comparative Evaluation of Three Preprocessing Methods for Extraction and Detection of Influenza A Virus Nucleic Acids from Sputum. Front Med (Lausanne). 2018 Mar 2;5:56. 
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