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
