92 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS abnormalities in the hair structure. But few data (10) have been reported about the composition of proteins from the hair of humans belonging to different ethnic groups. The purpose of this study was to characterize sulfur protein electrophoretic patterns of hair from individuals of various ethnic groups. Our investigations suggest that the variability observed is related to hair color independently of the donor's racial origin. MATERIALS AND METHODS HAIR SAMPLES Natural tresses free from previous cosmetic treatments from European, African, Indian, and Asiatic subjects were washed with 10% sodium lauryl sulfate (SDS), rinsed with tap water, and air dried. Hairs were cut in the middle part of the tresses (3 to 4 cm length at about 1.5 cm from the proximal root part of hair). To control a possible effect of weathering, a natural Caucasian brown hair tress was exposed for three months under daylight this tress was mounted on a specimen rack and directly exposed to climatic conditions. The total solar energy delivered was about 150 KJ/cm 2. The effect of normal weathering was studied on 1 cm of the proximal root part of hair and 1 cm of the distal end of natural Caucasian hair (hair length about 10 cm). EXTRACTION AND ALKYLATION PROCEDURE Three milligrams of hair were delipidized by immersion in successive baths of petro- leum ether and ethanol and subsequently rinsed with water. Fibers were cut into small pieces. Soluble proteins were extracted with 300 •1 0.05 M Tris HCI, pH 9.3, con- taining 8 M urea and 0.05 M dithiothreitol for 18 hours at room temperature and then treated with 6 •Ci of 2-(•4C)iodoacetic acid (specific activity 57 •Ci/mmole, Amer- sham, U.K.) according to Marshall and Gillespie (1). ELECTROPHORESIS OF SCM PROTEINS SDS-PAGE was performed in the system described by Laemmli (11) but using a step- wise separating acrylamide gel (10-15%) as reported in (1). For the 2-D electrophoresis analysis, the first-dimension separation was carried out in 8 M urea at pH 8.9 in a glass tube using the method of Davis (12). The gel rod was then equilibrated in 0.06 M Tris HCI buffer, pH 7.0, containing 2.3% SDS before being placed on the top of the polyacrylamide slab (11). DETECTION OF PROTEINS Gels were revealed by the fluorographic method of Laskey and Mills (13). Autoradiog- raphy was performed at -80øC using an X-Omatt Kodak film. ESTIMATION OF EXTRACTED PROTEINS Protein amounts were determined by the colorimetric method of Bradford (14) using a Biorad standard kit.

PROTEINS OF HAIR 93 AMINO ACID ANALYSIS Hair samples were hydrolyzed in vacuo with constant boiling HCI at 108øC for 22 h and freeze dried. The hydrolysate was adjusted to pH 7.8 and shaken with air to oxidize cystine. The content of amino acids was estimated with a modified Beckman (- 120C) amino acid analyzer. RESULTS ELECTROPHORETIC PATTERNS OF ALKYLATED PROTEINS EXTRACTED FROM A EUROPEAN BROWN HAIR The SDS-PAGE electrophoretic pattern of SCM proteins extracted from Caucasian brown hair is shown in Figure lb. It displays two major groups of bands: The first group corresponds to the LSP and consists of five polypeptides with molecular weights ranging from 75 Kd to 35 Kd. The second group contains the HSP which are resolved in eight bands ranging from 30 Kd to 14 Kd. The 2-D analysis (Figure la) shows six spots of LSP proteins and eight spots of HSP. At pH 8.9, HSP are characterized by a higher mobility than LSP. Figures la and lb will serve as reference patterns. ELECTROPHORETIC PATTERNS OF SCM PROTEINS FROM WEATHERING HAIRS The brown hair exposed (as reference) to prolonged daylight exposure shows a marked decrease of 87% of solubilized protein yield and only exhibits HSP after electrophoretic analysis (Figure 2a). Figure 1. Autoradiographies of two-dimensional electrophoresis (la) and SDS-PAGE (lb) of alkylated proteins extracted from European brown hair.