How to estimate the total protein from the intact cells?

Emir Khatipov khatipovNO at
Wed Jul 10 18:24:00 EST 2002

Check BCA protein assay kit from Pierce (no affiliation). It allows to
measure protein concentration down to 5ug/ml and can tolerate quite high
detergent concentrations (e.g. 5% SDS). I suggest you to try extracting the
protein from your samples using detergents (you should try several to
determine which one is better).

"Elinor Chen" <chenq129 at> wrote in message
news:d7b75d4c.0207081951.425c6fbd at
> Thanks, Rene.
> The problem is that the biological sample is quite low. All of them
> are microorganisms or from fraction of microorganisms. I intend to use
> Nano Organe kit to test the lower protein content. But not sure if it
> will be interfered by the detergent or buffer.
> Now, I need a lysis method which can extract the total protein
> content. It seems most research on extract of soluble protein. How to
> extract the membrane protein along with the soluble protein.
> Thanks.
> Elinor
> renevanwezel at (Rene) wrote in message
news:<fc41d9d1.0207080101.17490d09 at>...
> > Elinor,
> >
> > Kjeldahl is absolut, but nasty and needs lots of material, as already
> > noted.
> >
> > If your samples are relatively the same (kind of organisms etc) and
> > you are not interested in absolute amounts but in say, sample2
> > contains 1.5 times the amount of proteins as sample1, you can get away
> > with standard biochemical spec methods like the biurete test. I would
> > recommend Bradfords reagent, e.g. from Biorad. Very sensitive. Just
> > homogenize your sample in extraction buffer in a mortar or so, spin
> > down in a eppendorf tube and use the supoernatant for the test.
> >
> > Rene

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