finding GFP's mass

Emir Khatipov ekhatipo at NOSPAMmidway.uchicago.edu
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.
Emir

"Frederic Langlois" <ye.midget.pirates.deleted.my.account at the.seven.seas>
wrote in message news:eppz6.12265$up4.324633 at carnaval.risq.qc.ca...
> Hello.. I'm trying to figure out the different ways to calculate a
protein's
> 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
low
> range standard markers. I made a standard curve of the standards Rf value
(Y
> axis) and the molecular weight (X axis). I extrapolated the GFP's mass
using
> 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
>
weight1)+(n2*mol.weight2)+...(n20*mol.weight20)]/[(n1+n2+...n20-1)*33g/mol]
>
> 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
are
> 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
>
>
>





More information about the Proteins mailing list