Page 121 - Basic Principles of Textile Coloration

110 PROTEIN FIBRES

Table 7.1 continued

Mol % Nature of

Amino acid Structure(a) (from two sources) side-chain

Glutamic acid(c) HOOCCH2CH2CHCOOH 11.9 11.9 Acidic
Histidine NH2 0.9 0.8 Basic
6.8 6.9
N CH2CHCOOH Basic
NH2
N Basic
H
Sulphur-
Arginine H2NCNH(CH2)3CHCOOH containing
HN NH2 Sulphur-
containing
Lysine H2N(CH2)4CHCOOH 3.1 2.8 Heterocyclic
Methionine NH2
Cystine(d) Heterocyclic
H3CS(CH2)2CHCOOH 0.5 0.4
NH2

HOOCCHCH2SSCH2CHCOOH 10.5(e) 10.0(e)

H2N NH2

Tryptophan

Proline N CH2CHCOOH 5.9 7.2
H NH2

N COOH
H

(a) Shading indicates identity of side-chain
(b) Includes asparagine residues
(c) Includes glutamine residues
(d) Includes oxidation by-product, cysteic acid
(e) Values are for half-cystine