With more information, this sounds like partially misfolded protein, on top
of which it is very likely to be in complex with DNA. You can't rely on
either method for accurate protein concentration, the best you can do is to
use denaturing conditions (that may be difficult with some of the assays).
Take a spectrum of your stuff - you will immediately see the DNA/protein
absorption peak ratio.
Sounds like a potential candidate for MBP fusion expression...
A.G.E.
<selphydeg at yahoo.com> wrote in message
news:20030108184105.17919.qmail at ww02.hostica.com...
> Here are a list of characteristics associated with this protein. I will
be grateful if anyone can make something out of this.
>> -Very different concentration when measured with BCA and Biorad assay
(both assay use BSA as standard).
>> -Heat supernatant does not work with Biorad assay unless DNAase and RNAase
are added (possible protein-DNA complex formation after the heat step)
>> -Heat supernatant is fairly clean, but the residual proteins are
impossible to get rid of using column or ammonium sulfate precipitation.
>> -The salted out protein has a gelatin like consistency.
>> -This is a basic protein, and is not stable in pH<7. The buffer I use now
is Tris-HCl pH 8.0.
>> -After breaking the cell, there are some soluable protein, and some
inclusion bodies (50:50).
>> -The protein precipitate when it is >1.5 mg/ml. (tried adding metal,
salt, and glycerol).
>>>>http://biowww.net/mynews/tree.php?group_name=bionet.molbio.proteins&begin=0
