Fig. 3. Recombinant human frataxin^56–210 and endogenous human frataxin in whole cell extracts exhibit similar binding profiles.

Samples of recombinant frataxin^56–210 and cellular frataxin (from lymphoblast cell extract) were prepared at concentrations empirically determined to generate approximately equal dipstick signals (~25,000 units). The two samples were then serially diluted in 2-fold steps, frataxin levels measured, and the results plotted by pairing the starting high end samples and each pair of subsequent 2-fold diluted samples. The strong linear relationship between the two sample sets indicates immunological equivalence of the two forms of frataxin as measured in the dipstick assay.