Figure: Mark-It West (blue) and Mark-It Standard (red) were resolved on a 4-20 % gradient gel. After staining band positions were measured and the ratio to the front (Rf) was calculated.
The data were transferred to a spread sheet program and a trend line and the least square deviation from the actual values was calculated. R² indicates the regression coefficient for the linear regression line that was calculated by the least squares method. A value of 1 would indicate an identical fit of the values with the regression line.
Obviously for the low molecular weights the standard proteins deviate to some extent from the predicted linear relationship between molecular weight and Rf-value.
This property makes our recombinant markers the first choice for the determination of molecular weights!