poly-L-Histidine (Sigma P9386, MW 5000 to 15 000 Daltons)
mw132 at mole.bio.cam.ac.uk
Fri Jul 27 15:54:06 EST 2001
I am using this product as a positive control in a blot with a his
tagged protein BUT I have noticed a few things about it that puzzel me. I
thought that it would act just like a protein, so I tried dissolving 10mg
in 1ml water. No dissolution. Then I tried adding acid to 1M (later the
Sigma help people told me 0.1M was what they used). It dissolved quickly.
BUT when I added 10 micolitres to 5 microliters of my 3x protein loading
buffer there was immediate precipitation. I heated the sample and loaded
my PAGE gel anyway, then stained the eppendorf tube - it turned blue at
Soooooo, how does a person dissolve poly-L-Histidine and once dissolved
how does a person mix it with SDS without precipitation. I hate to misuse
a reagent and loose most of it to precipitation.
(the Coomassie blue stained duplicate gel showed a broad 5kDa band so not
all was lost).
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