finding GFP's mass

Emir Khatipov ekhatipo at
Fri Apr 13 13:00:03 EST 2001

I think your question was mainly about whether there are other "wetlab"
methods  of determination of molecular weight of a protein. In addition to
SDS-PAGE you used, there is also native electrophoresis, gel filtration,
ultracentrifugation, mass spectrometry, chemical methods, like Kjeldal
analysis, and others.

"Frederic Langlois" < at>
wrote in message news:eppz6.12265$up4.324633 at
> Hello.. I'm trying to figure out the different ways to calculate a
> mass for an assignment. In this particular case I want to know the mass of
> the green fluorescent protein (GFP).
> 1) The first method I have used is the SDS-PAGE electrophoresis with the
> range standard markers. I made a standard curve of the standards Rf value
> axis) and the molecular weight (X axis). I extrapolated the GFP's mass
> it's Rf value.
> 2) Then I searched many databanks and found GFP's amino acid sequence. I
> used this equation to find GFP's mass:
> mass = [(n1*molecular
> where 1=glycin; 2 to 20= all the other amino acids
>       n=the sum of the amino acids of each kind
>       33g/mol=a water molecule's molecular weight (approximately)
> I substrated the water molecules that are "lost" when the peptidic bonds
> made.
> I converted the molecular weight in Dalton units...
> 3) what are the other methods I can use to find the mass of this protein?
> Thanks in advance,
> Frederic Langlois

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