RE: storage of enzyme solution

Simon Gates (sgates@proteome.org.au)
Wed, 10 Feb 1999 09:39:31 +1100

Dear ABRFers,
I was reading the couple of e-mails about storage =
of=20
enzymes and found the information quite interesting. We are currently=20
considering better methods for storage of trypsin to reduce the amount of=
=20
trypsin we waste. I am involved in the protein sequencing lab at our=20
facility and haven't performed a tryptic digest myself but we have a lab=20
involved in peptide mass fingerprinting who perfom digests on a routine=20
basis. My sources tell me trypsin has optimum activity at pH ~8.5 but=20
obviously storing in HCl will mean storing at a much lower pH. Our mass=20
spec lab currently stores their trypsin at pH 8.5 (-20C) freezing it once=
=20
and discarding any left over. I was wondering if those who store their=20
trypsin in HCl increase their pH before use and how they do it.

Thanks in advance for all replies,

Simon

Simon Gates
Australian Proteome Analysis Facility
Level 4 Building F7B
Macquarie University
NSW Australia 2109

Ph (02) 9850 6207
Fax (02) 9850 6200
E-mail sgates@proteome.org.au

-----Original Message-----
From: Marcus Macht [SMTP:Marcus.Macht@uni-koeln.de]
Sent: Tuesday, 9 February 1999 19:40
To: Recipients of ABRF List
Cc: abrf@aecom.yu.edu
Subject: Re: storage of enzyme solution

At 15:50 08.02.99 -0600, you wrote:
>Hi, everyone,
>We typically play with the digestion of very small size of protein=20
samples.
>I wonder how to keep the activity of the unused enzyme solutions. Shoul=
d=20
I
>keep them freezed or at +4C. How long can enzymes be alive after they a=
re
>freezed. Many thanks for the imput.
>Jiang
>

Dear Jiang:

We have made very good experiences with storing a stock solution of
TPCK-trypsin in 1mM HCl (c~1=B5g/=B5l) at -23=B0C in the freezer. This st=
ock
solution will normally stay in a good condition for at least half a year.
Glu-C (from Roche Diagnostics [formely Boehringer Mannheim] in PBS or 50 =
mM
ammonia bicarbonate) and Lys-C (sequencing grade in Tris-buffer at 0.1
=B5g/=B5l from Roche Diagnostics) can also be stored in a frozen solution=
for a
couple of weeks. I had a solution of Lys-C in the freezer for over a year
and it showed still good enzymatic activity (albeit I did not quantitize=20
it).
Hope this helps.

Yours sincerely,

Marcus
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Marcus Macht
ZMMK-Servicelabor
Joseph-Stelzmann-Str. 52
50931 Koeln
Tel.: +49 221 478-6995
Fax: +49 221 478-6977
e-mail:Marcus.Macht@uni-koeln.de
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