Page 80 - Handbook of Properties of Textile and Technical Fibres

Properties of wool 61

Table 3.1 Amino acid composition of Merino wool

Amino
acid
Amino acid content a Side group Nature of side group
Glycine 8.4 eH Aliphatic hydrocarbon
Alanine 5.4 eCH 3 Aliphatic hydrocarbon
Valine 5.6 eCH(CH 3 ) 2 Aliphatic hydrocarbon
Leucine 7.7 eCH 2 CH(CH 3 ) 2 Aliphatic hydrocarbon

Isoleucine 3.1 eCH(CH 3 ) CH 2 CH 3 Aliphatic hydrocarbon

Phenylalanine 2.9 eCH 2 C 6 H 5 Aromatic hydrocarbon

Serine 10.4 eCH 2 OH Hydroxyl

Threonine 6.4 eCH 2 (OH) CH 3 Hydroxyl

Tyrosine 3.8 eCH 2 C 6 H 4 OH Hydroxyl

Aspartic acid b 6.5 eCH 2 COOH Acidic

Glutamic acid c 11.9 eCH 2 CH 2 COOH Acidic

Lysine 0.9 eCH 2 CH 2 CH 2 CH 2 NH 2 Basic

Arginine 6.9 e(CH 2 ) 3 NH C(NH)NH 2 Basic

Histidine 2.9 N=CH Basic
N=CH
– CH 2 2 NH
NH
CH
C=CH
C=CH
Methionine 0.5 eCH 2 CH 2 S CH 3 Sulfur containing

Cystine 10.3 d eCH 2 S S CH 2 - Sulfur containing

Tryptophan e 0.5 – CH 2 2 ·C Heterocyclic
CH ·C
CH
CH
NH
NH
Proline 6.6 – CH 2 2 Heterolytic
CH
CH
CH 2 2
– CH 2 2
CH
a
Residues/100 residues (Bradbury et al., 1968; Leeder and Marshall, 1982).
b
Includes asparagine.
c
Includes glutamine.
d
The value shown is for the reduction product, cysteine (also termed “half-cystine”).
e
Tryptophan is destroyed under the conditions used for these analysis; values of about 0.5% residues have been obtained by
alternative techniques (Rippon et al., 2016).