PMSF? - (May/31/2007 )

Why is it necessary to use PMSF when using Proteinase K? I know that it inhibits the Proteinase, but why does the inhibitor need to be added? Do I need to incubate the samples after adding PMSF or is the inhibition instant?

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It depends on your future tasks. I think that you should incubate for a short period of time with PMSF because of all the reactions ( especially this type) need time to take place ( it depends on reaction kinetic). Only note that PMSF is unstable in aqueous solutions and degrade during 2 hour completely.

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what are your exp in which you use PMSF with protéinase K ?
I'm curious on that point...

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I am testing if a protein of my interest is attached on the surface of the cell or is it located in the bacterial cell. I am not sure why do I have to use PMSF. Proteinase K cannot degrade the bacterial cell anyhow so there is no danger of cell lysis and degradation of intracellular proteins. Any ideas:P?

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WELL i think that proteinase K may not be inhibited by pmsf and the other protease should be ?

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Hmm, probably good point but I think PMSF actually inhibits proteinase K and not the other extracellular protease we have in our bact. system. Still confused about it but will do more search:). Thanks!

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