Ting,
Keep in mind that trypsin specifically binds the side-chain of arginine
which is a guanidino group. Therefore, guanidinium ions are competitive
binding inhibitors of trypsin. Urea, guanidine, and all chaotropes will
denature trypsin as you raise the concentration of these reagents (thus
inactivating the enzyme) but guanidine has this additional competitive binding
inhibition of trypsin.
Jacob Bongers
SmithKline Beecham Pharmaceuticals
jacob_s_bongers@sbphrd.com
TWong@biomira.com on 18-Aug-2000 11:48
To: abrf
cc: (bcc: Jacob S Bongers/DEV/PHRD/SB_PLC)
Subject: re: trypsin activity in guanidine hydrochloride
I have encountered incomplete digestion of protein using trypsin. Since
I was given the impression that trpytic digestion of protein can be done
in mild denaturing condition such as 1-2 M 0f guanidine hydrochloride, I
tried that but was not successful. The trypsin seemed to lose activity
even at S/E (w/w) of 5 to 1 (20:1 was used in normal codition). I wonder
if there is anything that I am not aware of in applying such condition
for trypsin. Thanks in advance for your advice.
Ting Wong
Biomira Inc.
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