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Proteinase K activation/preparation - water or buffer in proteinase K (Sep/12/2005 )

I am accustomed to using the Qiagen proteinase K, which comes preactivated. Out technician decided to buy the Fisher brand because it was cheaper. The online fisher datasheet says that it must be activated in either 0.5% SDS or 1% Triton* X-100. The tech things that you can dissolve it simply in is the case with Sigma proteinase K. Does anybody know if this is true...i.e whether it will activate in water or if I have to go through the hassle of making the 0.5% SDS or 1% Triton* X-100.

Thanks in advance


regarding the fact that you bought this one cause it was cheaper it would be quite ironic to destroy your RNAse by just water. Moreover, there is a risk that in ddH2O your protein precipitate, isn't there?



Most Prot K that I know of is diluted in water, then when using it, add a detergent such as SDS or triton and TE to the reaction, as these increase the activity of the enzyme as well as inhibiting RNAses and DNAses.



I dilute my proteinase K in HBSS or PBS, just to maintain salts concentration. I do not need to activate it. I diluted it 1000 more concentrated than I use it and froze it in small aliquots. I thaw one part take what I need and freeze it back quickly.