Question

A gel filtration column was calibrated by measuring elution volumes for two proteins of known mass:

Glutamate dehydrogenase: 290 kDa with elution volume 20.8 mL

Serum albumin: 37 kDa with elution volume 42.5 mL

Use these values to determine the equation of the straight line graph that relates log molar mass to elution volume.

The elution volume of an unknown protein was 22.7 ml. Use the equation just determined above to estimate the molar mass of the protein in kDa units.

Please don't round your answer until the end to ensure your answer is within the accepted range.

Round your answer to the nearest whole number (e.g. If you calculated 27.52, input your answer as 28).

Answer 1

The molar mass (M) of a protein is inversely related to its elution volume.

The plot of Log(M) and elution volume can be drawn as follows.

The equation of the line: Log(M) = -0.04121*Elution volume + 3.31951

Here, Elution volume = 22.7 mL, then Log(M) = -0.04121*22.7 + 3.31951

i.e. Log(M) = 2.384043

Therefore, the molar mass of the unknown protein (M) = 242 g/mol