Characterization of the H and L Subunit Ratios of Ferritins by SDS Capillary Gel Electrophoresis


Sodium dodecyl sulfate–capillary gel electrophoresis (SDS–CGE) was used to characterize the H- and L-subunit ratios of several mammalian ferritins and one bacterioferritin. Traditionally, SDS–PAGE has been used to characterize the H- and L-subunit ratios in ferritin; however, this technique is relatively slow and requires staining, destaining, and scanning before the data can be processed. In addition, the H- and L-subunits of ferritin are fairly close in molecular weight (∼21,000 and ∼20,000, respectively) and are often difficult to resolve in SDS–PAGE slab gels. In contrast, SDS–CGE requires no staining or destaining procedures and the peak quantitation is superior to SDS–PAGE. SDS–CGE is effective in quickly resolving the H- and L-subunits of ferritins from horse spleen, human liver, recombinant human H and L homopolymers, and mixtures of the two- and the single-subunit of a bacterioferritin from Escherichia coli. The technique has also proven useful in assaying the quality of the protein sample from both commercial and recombinant sources. Significant amounts of low-molecular-weight degradation products were detected in all commercial sources of horse spleen ferritin. Most commercial horse spleen ferritins lacked intact H-subunits under denaturing conditions.


Molecular, Cellular and Biomedical Sciences

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Analytical Biochemistry



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