Description
Highly characterized for more consistent performance, Proteinase K is a subtilisin-related serine protease that will hydrolyze a variety of peptide bonds. Proteinase K is active in a wide range of temperatures and buffers with optimal activity between 20 and 60°C and a pH between 7.5 and 12.0 (1, 2). Activity is stimulated when up to 2% SDS or up to 4 M urea are included in the reaction (3). Calcium is important for thermostability of Proteinase K but it is not required for catalysis, therefore Proteinase K is also active in buffers containing chelating agents such as EDTA (4).
Figure 1: Lot-to-Lot Variability - Competitor Comparison
Activity measurements from three NEB lots of Proteinase K were compared to three lots from another vendor. Reported activity for all NEB lots is 800 Units/ml ± 10% (indicated as a black line with error bars). Direct measurement of the competitor’s material using an assay reported on the vendor’s literature, demonstrated a dramatic over-assessment of all three lots.
Figure 2: Activity Measurements - Competitor Comparison
Activity measurements from a single NEB lot were compared to a single lot from seven other vendors. Proteinase K from NEB is sold at 800 Units/ml ± 10% (indicated as a black line with error bars), whereas most other vendors sell Proteinase K as > 800 or > 600 Units/ml. While Proteinase K from some vendors was close to the stated activity values, others varied significantly from the expected amount.
Protein Concentration
20 mg/ml, approximately, as determined by UV absorption at 280 nm.
Product Source
Engyodontium album (Tritirachium album)
- This product is related to the following categories:
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Protein Tools,