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Getting rid of PMSF - (Apr/28/2001 )

how long does it take for PMSF to lose its activity. i used it in my protein prep, this time i wantto deactivate the PMSF before i go to my next step, which is doing a thrombin digest.

any suggestions are welcomeanita


From what I have read, PMSF loses its activity in as little as 7 minutes in aqueous solutions.


The rate at which PMSF loses its activity depends on pH and temperature; as pH increases, the rate increases. The only values I found were in a booklet put out by BoehringerMannheim: the half-life is 55 min at pH 7.5 in HEPES.


Yes, that's right PMSF degrades in 55 min. at 25 C, at 20 C PMSF degrades in 100 min.

I usually use Pefabloc SC aka AEBSF in place of PMSF because it is more stable and creates a larger window to work in.

good luck.