406 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS fraying of large fiber bundles (Figure 1F). Relaxed fibers were similar in overall appearance to permanent waved fibers except that less cortical fraying was noted (Figure 1C). Bleached fibers showed complete cuticle removal with no evidence of damage to the cortex (Figure 1D), similar to the control. These results suggest that the treatments investigated may differentially affect the adhesion of cuticle to cortex. AMINO ACID ANALYSIS The amino acid composition of the untreated whole hair sample (Table I) was generally similar to that of several other published reports (2,3,10-12) with some Table I Amino Acid Content of Whole Hair Samples. (tool/1000 tool total amino acids analyzed) Virgin Bleached Permanent Reduced Relaxed Amino Acid Hair Hair Waved Hair Hair Hair Alanine 48.5 _+ 0.9 44.4 + 1.1 48.2 _+ 0.2 50.7 _+ 1.0 51.0 _+ 0.2 Valine 56.8 _+ 0.5 58.7 _+ 0.4 58.8 _+ 1.3 58.2 _+ 3.5 60.6 _+ 2.4 Leucine 62.0 + 1.0 63.6 + 0.4 64.3 + 0.8 71.1 + 3.5 69.8 + 0.1 Isoleucine 25.0 +_ 1.0 26.4 + 0.4 27.0 + 0.0 28.7 + 1.5 28.8 + 0.1 Alloisoleucine n.d. n.d. n.d. Trace 6.4 + 1.4 Proline 83.0 + 0.7 80.1 + 3.9 80.3 + 0.1 108.7 +_ 6.2 88.9 + 2.5 Phenylalanine 16.1 + 0.3 16.4 + 0.3 16.8 + 0.4 17.2 + 0.1 17.7 + 0.3 Methionine 4.2 _+ 0.0 3.7 _+ 0.4 3.7 +_ 0.1 7.3 -+ 1.8 6.4 _+ 1.8 Glycine 61.1 + 0.1 56.0 + 0.4 60.8 + 0.1 65.2 + 1.2 65.4 _+ 0.3 Serine 114.9 + 2.9 114.1 + 1.9 109.5 + 0.1 109.9 + 0.5 122.7 + 0.2 Threonine 72.8 + 1.1 73.9 + 0.8 72.8 + 0.2 71.9 + 1.2 79.3 -+ 0.3 Tyrosine 21.1 + 0.1 20.7 + 0.3 21.7 + 0.1 22.7 + 0.0 23.8 + 0.3 Aspartic Acid 54.O + 0.0 55.5 + 0.5 55.1 + 0.7 58.7 + 0.8 59.7 + 0.2 Glutamic Acid 125.7 + 0.4 127.1 + 1.2 126.9 + 0.9 133.5 -+ 0.6 137.4 + 0.3 Lysine 26.5 +_ 1.7 25.9 + 2.1 27.2 + 0.7 24.1 + 0.1 24.9 _+ 1.0 Arginine 62.8 +_ 3.9 63.6 + 4.7 67.1 + 0.8 57,3 + 1.7 66.3 + 4.7 Histidine 8.8 + 0.4 8.3 + 0.7 9.2 + 0.2 7.8 + 0.1 8.5 + 0.4 Cysteic Acid Trace 26.7 + 1.6 4.8 + 0.2 2.0 + 0.2 2.3 + 0.3 Half-cystine 156.4 +_ 4.5 135.3 -+ 0.2 140.7 + 1.7 95.8 + 0.1 43.3 _+ 2.7 Lysinoalanine n.d. n.d. n.d. n.d. 3.4 + 0.1 L-+-meso- n.d. n.d. n.d. 7.8 _+ 0.5 40.2 + 1.0 lanthionine Carboxymethyl- n.d. n.d. 5.6 + 1.7 3.4 _+ 0.6 n.d. thio-cysteine n.d.--not detectable. Values given _+ the standard deviation with n = 2. differences in the levels of half-cystine, arginine, proline and methionine these may be due to the methods of preparation or the hair source, or both. Amino acid analysis of the separated cuticle and cortex of virgin hair showed that cuticle protein (Table II) differed from cortex (Table III) and whole hair protein in its amino acid content. In agreement with data from other laboratories (10-12) isolated cuticle protein from untreated hair contained significantly more glycine, serine and some trend to higher levels of sulfur containing amino acids (methionine and cystine) per mole than in the cortex or the whole hair. In addition, the cuticle contained lower quantities of acidic

EFFECT OF CHEMICAL TREATMENTS ON HAIR 407 Table II Amino Acid Analysis of the Cuticle Fraction. (tool/1000 tool total amino acids analyzed) Virgin Bleached Permanent Reduced Relaxed Amino Acid Hair }lair Waved }lair Hair Hair Alanine 58.4 _+ 0.9 55.7 -+ 1.5 55.8 -+ 1.0 53.9 -+ 0.1 53.8 _+ 0.6 Valine 66.1 _+ 2.2 66.6 _+ 3.1 65.8 _+ 0.0 61.6 _+ 2.2 61.2 _+ 1.3 Leucine 45.8 _+ 4.0 44.7 _+ 0.4 49.1 _+ 0.3 54.6 _+ 0.3 62.2 _+ 5.0 Isoleucine 19.7 _+ 4.4 17.4 _+ 0.2 22.1 _+ 0.2 22.0 _+ 2.5 24.4 _+ 3.2 Alloisoleucine 5.1 _+ 3.1 n.d. 6.3 _+ 0.1 Trace 7.8 _+ 3.1 Proline 98.7 _+ 3.3 99.1 + 1.0 98.6 _+ 0.1 99.3 -+ 0.9 94.0 _+ 0.9 Phenylalanine 11.5 _+ 0.0 12.2 _+ 0.1 12.2 _+ 0.1 14.0 _+ 0.1 15.1 _+ 0.1 Methionine 6.9 -+ 2.6 3.6 _+ 0.2 9.2 _+ 0.5 7.0 •- 2.3 9.0 _+ 0.9 Glycine 98.0 _+ 1.3 89.4 + 1.1 90.8 _+ 1.6 83.2 _+ 0.5 76.4 _+ 1.1 Serine 169.8 _+ 4.2 168.4 _+ 0.6 170.6 _+ 1.3 144.3 _+ 1.0 144.1 _+ 2.2 Threonine 42.2 _+ 1.2 46.5 _+ 0.2 44.2 + 0.4 56.5 _+ 0.4 65.5 + 0.8 Tyrosine 17.1 _+ 0.4 15.4 _+ 0.1 16.9 _+ 0.1 19.3 -+ 0.3 21.6 _+ 0.4 Aspartic Acid 31.3 _+ 0.9 35.0 + 0.0 33.1 -+ 0.3 42.8 _+ 0.3 48.2 _+ 0.6 Glutamic Acid 94.6 _+ 2.7 98.6 _+ 0.9 96.3 _+ 0.5 110.8 _+ 0.4 122.1 _+ 1.5 Lysine 34.1 _+ 4.3 29.6 _+ 1.4 30.4 _+ 0.1 30.3 _+ 1.9 29.0 _+ 3.9 Arginine 23.4 + 3.1 23.6 + 1,4 21.4 _+ 0.6 40.1 _+ 2.6 52.4 _+ 7.5 Histidine 4.7 _+ 0.7 4.4 _+ 0.2 4.5 _+ 0.1 6.4 _+ 0.5 7.6 _+ 1.1 Cysteic Acid 4.4 _+ 0.5 44.2 _+ 0.2 9.6 -+ 0.1 3.2 _+ 0. i 2.9 _+ 0.1 Half-cystine 168.8 _+ 6.6 146.0 _+ 1.4 156.9 _+ 0.3 144.3 _+ 1.2 71.8 _+ 0.3 Lysinoalanine n.d. n.d. n.d. n.d. 4.1 _+ 0.6 L-+-meso- n.d. n.d. n.d. 5.0 _+ 0.2 35.2 _+ 3.8 lanthionine Carboxymethyl- n.d. n.d. 6.8 _+ 0.1 2.5 _+ 0.1 n.d. thio-cysteine n.d.--not detectable. Values given _+ the standard deviation with n = 2. (aspartic, glutamic), basic (arginine and histidine) and aromatic (phenylalanine and tyrosine) amino acids than did whole hair or isolated cortical preparations, as well as lower levels of leucine and threonine. The effect of chemical treatments on whole hair, cortex and cuticle amino acid composition is also shown in Tables I-III. In comparison to untreated whole hair, bleaching, TGA-reduction, permanent waving and alkali relaxation resulted in loss of half-cystine residues from the hair (13%, 39%, 10% and 72%, respectively). Chemical effects on the amino acid composition were most pronounced for the cuticle. Once again half-cystine residues were extensively decreased by the treatments. Bleaching and reduction of hair resulted in a 15% loss of half-cystine in the cuticle while alkali relaxation gave a decrease of 57%. Moreover, bleaching resulted in a decrease in half-cystine (15%) and especially methionine (48%) in the cuticle, while permanent waving increased the methionine found in the cuticle. Glycine and serine, two of the amino acids which are found in high concentrations in untreated cuticle, were also lowered to about the same extent by reduction and relaxation treatments (15-22%). Amino acid residues which showed an increase in the cuticle due to reduction and alkali treatments were leucine, phenylalanine, threonine, tyrosine, aspartic acid, glutamic acid, and histidine.