Re: Proteinase K Mystery (Paul Klosen)

> (snip) So my question is, are all Proteinase K's
>born equal?  Could this Gibco brand of Proteinase K be weaker?

Definitely, YES. It's an enzyme and its mostly sold on the basis of weight,
not activity. We use proteinase K for in situ hybridization, where the
digestion is pretty critical for sensitivity and reproducibility of the
labeling. We test each batch we buy on a test tissue with a test probe to
ensure reproducibility. And I mean each batch, even if the manufacturer
says it comes from the same lot.
BTW, in our hands the most standardized proteinase K is from Roche
(previously Boehringer). No affiliation of course with this company.
Also, we freeze in individual aliquots that are unfrozen only once and then
thrown away.

My 2 cents worth


                         (o -) O
Paul Klosen, PhD
CNRS UMR 7518 Neurobiologie des Fonctions Rythmiques et Saisonnieres
Universite Louis Pasteur
12 rue de l'Universite
F-67000 Strasbourg, FRANCE
tel:    fax:

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