Proteinase K thawed...AOK??

Rafa Maldonado Rafael at
Fri Jan 21 22:21:17 EST 1994

(With all my compliments and good intentions to Maniatis's Book)

Proteinase K usually precipites at Maniatis's concentration at -20
during prolonged conservation (at least, Boehringer Mannheim's). My
suggestions is to use a lower concentration, 5 mg/ml is OK. And advoid
SDS in frozen preparations of anything if you can, it always
precipites. It is no necessary for the conservation of the enzyme, but
for good proteinase activity in the reaction, so don't forget add SDS
to your proteinase K reactions.

Of course, all of this happens in my hands!

Any suggestions more?

Rafael Maldonado
Howard Hughes Medical Insitute
University of Utah
Rafael at

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