How to estimate the total protein from the intact cells?

Rene renevanwezel at
Wed Jul 10 14:01:06 EST 2002

Sorry, can't help you here. You will never know how much protein
exactly will be going in solution, you have to go for a wet-chemical
(absolute) test if you're interested in fraction soluble/insoluble
BTW, Bradford is quite sensitive, microgram per ml range.
Good luck, Rene

chenq129 at (Elinor Chen) 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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