ELECTROPHORETIC VARIATION OF HAIR PROTEINS

Hair follicle cells secrete a complex assortment of proteins that form the hair shaft, and can be classified into two major groups. The low- sulfur proteins are keratins that contribute to the backbone of interm ediate filaments, and the high-sulfur proteins are associated with the se filaments. In the present investigation we describe a comparative e lectrophoretic study of normal human hair proteins from 182 individual s, including some families. Hair proteins were extracted in urea buffe r (pH 9.3), examined by 10% polyacrylamide gel electrophoresis (pH 8.8 ) in the presence of sodium dodecyl sulfate and stained with Coomassie brilliant blue. Eighteen bands appeared and were reproducible in most individuals, with apparent molecular mass ranging from 10.0 to approx imately 100 kDa. Based on the most prominent bands, an electrophoretic profile defined as the ''frequent profile'' was observed. This profil e was observed in 180 individuals and consisted of 6 prominent bands, 4 of them of apparent molecular mass in the 40-70-kDa range, which is characteristic of keratins (61.9 +/- 1.02, 58.5 +/- 1.21, 47.9 +/- 1.5 8, and 45.4 +/- 1.53 kDa), and 2 bands with lower molecular mass (18.9 +/- 0.75 and 13.7 +/- 0.91 kDa). In 2 samples from unrelated women, a n additional band of 42.1 +/- 1.72 kDa appeared. The meaning of this v ariant is still under investigation.