Characterization of the proteins of human hair and nail by electrophoresis.

Low-sulfur and high-sulfur proteins from human hair and nail were characterized by two-dimensional polyacrylamide gel electrophoresis. Apparent molecular weights (estimated by SDS electrophoresis) of low-sulfur and high-sulfur proteins were in the ranges 55,500-76,000 and 26,500-43,000, respectively, but these are probably higher than the real values (12-30% for low-sulfur, 75-150% for high-sulfur) because corresponding wool proteins behave anomalously in SDS electrophoresis. Isoelectric points of the low-sulfur proteins ranged from 4.9-5.4. Six low-sulfur and 7 high-sulfur major proteins were common to hair and nail from the same individual, but each keratin contained 1 additional major low-sulfur component which was not common. Variation, presumably of genetic origin, was observed in the low-sulfur and high-sulfur proteins of hair and nail.