Sephadex is the brand-name for a form of cross-linked dextran which can be used to pack a column for gel filtration. The elution characteristics of a protein in a Sephadex gel filtration column can be used to estimate that proteins molecular weight.
Parameters:
(1) void volume in mL
(2) elution volume for the protein in mL (volume eluted at the time of the absorbance peak)
elution volume to void volume ratio =
= (elution volume for the protein) / (void volume)
This ratio for a protein run on a column usually ranges from 1 to 2.
The plot of the ratio vs the LOG10(molecular weight) for a protein (semilog plot) is linear.
The slope and intercept for a sephadex column is affected by the type of sephadex (G-75, G-100, etc), column packing and run-time characteristics. Normally 2 or more proteins of known molecular weights are run to derive the line and then the unknown protein is run.
To read more or access our algorithms and calculators, please log in or register.
