Electrophoretic analysis of human hair keratins

Non S-carboxymethylated human keratins, extracted from the hair of individuals from 3 Italian families, were characterized by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF), after the separation of hair fibrous proteins (HFP) and hair matrix proteins (HMP) by gel filtration chromatography. By SDS-PAGE, HFP were separated into 3 polypeptide bands with apparent molecular weight (MW) 52 KDa, 44KDa and 40 KDa; by IEF they were separated into several polypeptide bands with apparent isoelectric point (pI) in the pH range 7.4-4.0. By IEF, HMP were separated into several polypeptide bands with apparent pI in the pH range 7.4-5.4. It was not possible to characterize HMP by SDS-PAGE since their concentration, obtained after gel filtration chromatography, was very low. However, total extracted hair keratins were separated by SDS-PAGE into the polypeptides of HFP and into two bands with apparent MW 16 KDa, and 12 KDa. It was not possible to point out any interindividual variability in the electrophoretic patterns, except for one woman, for whom cosmetic treatment of hair could not be excluded. Finally, electrophoretic patterns for subjects of the same family are more similar than for unrelated subjects. Electrophoretic analysis of fractionated hair keratins could be useful for a better characterization of these polypeptides in genetic studies.