As long as the Proteinase K has a similar concentration and activity specifications, it should be OK to use. Proteinase K, Molecular Biology Grade (NEB #P8107), is available for standalone purchase and can be used as a direct substitute for (NEB #P8200) in all Monarch protocols without any modifications.
However, many other Proteinase K products do not have the same specifications as NEB’s Proteinase K products (NEB #P8200 or #P8107), which has been highly characterized for more consistent performance. Additionally, NEB Proteinase K has no detectable endonuclease, exonuclease and DNase activity and is DNA-free. These specifications may be relevant for your downstream applications.
