ABSTRACT
Hair follicle cells secrete a complex assortment of proteins that form the hair shaft, and can be classified into two major groups. The lowsulfur proteins are keratins that contribute to the backbone of intermediate filaments, and the high-sulfur proteins are associated with these filaments. In the present investigation we describe a comparative electrophoretic study of normal human hair proteins from 182 individuals, including some families. Hair proteins were extracted in urea buffer (pH 9.3), examined by 1O per cent 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 approximately 100 kDa. Based on the most prominent bands, an electrophoretic profile defined as the "frequent profile" was observed. This profile was observed in 180 individuais and consisted of 6 prominent bands, 4 of them of apparent molecular mass in the 407O-kDa range, which is characteristic of keratins (61.9 ñ 1.02, 58.5 ñ 1.21, 47.9 ñ 1.58, and 45.4 ñ 1.53 kDa), and 2 bands with lower molecular mass (18.9 ñ 0.75 and 13.7 ñ 0.91 kDa). In 2 samples from unrelated women, an additional band of 42.1 ñ 1.72 kDa appeared. The meaning of this variant is still under investigation.