How stable is proteinase K?

Sunee Kertbundit - ST stskb at MUCC.MAHIDOL.AC.TH
Thu Jun 2 03:36:46 EST 1994

On 31 May 1994, Shiao Y. Wang wrote:

> I have traditionally dissolved proteinase K in water at 20mg/ml and stored
> it at -20 C (from Maniatis et al. 82). Often times, only ug's are needed
> and the stock soln gets frozen and thawed many times. Does anyone have
> some general guidelines on how stable proteinase K is to freezing and thawing?
> Should a tube be discarded after a predetermined number of thawing? Would
> it be better to dissolve the enzyme in a buffer? Perhaps with glycerol?
> Thanks in advance.
> Shiao Wang
> University of Southern Mississippi
You look at article - J. Campbell et al, FOCUS 16 (1994) 22-23.
According to this, proteinase K retained 99 % activity after 12
cycles of freezing/thawing and 98 % activity after storage at 
ambient temperature for 16 days.

Sunee Kertbundit
Mahidol University

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